PREVALENCE (PEDIATRIC AND ADULT POPULATION): Asthma is among the most common chronic diseases in both children and adults. According to the latest report from the Centers for Disease Control and Prevention, for the 3-year period between 2001 and 2003, about 20 million persons in the U.S. had asthma. Of these, 6.2 million were children and 13.8 million were adults. Current asthma prevalence was higher for children (8.5%) than adults (6.7%). In addition, boys (9.6%) had higher prevalence than girls (7.4%), whereas prevalence among women was higher (8.4%) than among men (4.9%). These statistics suggest that a considerable number of patients with asthma in childhood outgrow the disease, and those most likely to undergo asthma remission are male patients. (data source omitted in sample)
PREVALENCE: This report is one in a set of reports summarizing data from the 2006 National Health Interview Survey (NHIS), a multipurpose household health survey conducted by the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS). This report provides national estimates for a broad range of health measures for the U.S. civilian noninstitutionalized population of adults. In 2006, data were collected for 24,275 adults for the Sample Adult questionnaire. The final response rate was 70.8%. Among 220,267,000 persons aged 18 and older, the number (in thousands) with asthma (ever vs still) was estimated as 24,256 vs 16,057. The total number (in thousands) of persons in each age group is reported in parentheses, followed by the number (in thousands) who have asthma (ever vs still): male (106,252), 10,078 vs 5904; female (114,014), 14,178 vs 10,152; ages 18-44 years (110,391), 12,668 vs 7990; ages 45-64 years (74,203), 7806 vs 5576; ages 65-74 years (19,081), 2238 vs 1481; ages 75 and older (16,593), 1544 vs 1010; white (179,456), 19,476 vs 12,940; black or African American (26,223), 3124 vs 1996; Asian (10,066), 833 vs 535; Hispanic or Latino (28,664), 2345 vs 1447. (data source
omitted in sample)
PREVALENCE TRENDS: Based on the National Health Interview Survey, the prevalence of current asthma was reported as follows in males versus females (all ages): 2001, 8,580,000 vs 11,701,000; 2002, 8,461,000 vs 11,565,000; 2003, 8,213,000 vs 11,623,000; 2004, 8,937,000 vs 11,608,000. The current prevalence in 2004 was reported as follows for selected variables: race (white, 15,855,000; black, 3,376,000; other, 1,313,000); ethnicity (Hispanic or Latino, 2,124,000; not Hispanic or Latino, 18,421,000); age (0-4 years, 1,120,000; 5-14 years, 3,701,000; 15-34 years, 5,616,000; 35-64 years, 7,679,000; 65 or older, 2,429,000). During 2001-2003, the estimated average annual number of persons reporting an asthma attack during the preceding 12 months was reported as 4,730,000 males and 6,916,000 females. The number of males versus females was reported as follows by age: ages under 18 years, 2,412,000 vs 1,698,000; ages 18 or older, 2,319,000 vs 5,219,000; ages 0-4 years, 528,000 vs 379,000; ages 5-14 years, 1,563,000 vs 1,004,000; ages 15-34 years, 1,236,000 vs 2,020,000 (ages 15-19 years, 500,000 vs 533,000; ages 20-24 years, 308,000 vs 511,000; ages 25-34 years, 428,000 vs 976,000); ages 35-64 years, 1,160,000 vs 2,890,000; ages 65 and older, 243,000 vs 624,000. The estimated number of persons with a self-reported asthma attack during the preceding 12 months was reported as follows in males versus females: 1999, 4,310,000 vs 6,178,000; 2000, 4,567,000 vs 6,413,000; 2001, 4,894,000 vs 7,092,000; 2002, 4,863,000 vs 7,045,000; 2003, 4,434,000 vs 6,612,000; 2004, 5,164,000 vs 6,520,000. The corresponding data were reported as follows in whites versus blacks: 1999, 8,214,000 vs 1,513,000; 2000, 8,568,000 vs 1,605,000; 2001, 9,277,000 vs 1,898,000; 2002, 9,112,000 vs 1,962,000; 2003, 8,299,000 vs 1,850,000; 2004, 9,003,000 vs 1,958,000. The corresponding data were reported as follows in Hispanic/Latinos versus non-Hispanic/Latinos: 1999, 1,089,000 vs 9,392,000; 2000, 1,087,000 vs 9,892,000; 2001, 1,164,000 vs 10,822,000; 2002, 1,087,000 vs 10,821,000; 2003, 1,318,000 vs 9,728,000; 2004, 1,242,000 vs 10,442,000. The corresponding data were reported as follows for ages under 18 years versus ages 18 or older: 1999, 3,799,000 vs 6,689,000; 2000, 3,998,000 vs 6,982,000; 2001, 4,156,000 vs 7,830,000; 2002, 4,197,000 vs 7,711,000; 2003, 3,975,000 vs 7,071,000; 2004, 3,975,000 vs 7,709,000. (data source omitted in sample)
PREVALENCE: In the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988 to 1994, prick-puncture allergy skin tests to 10 allergens were administered to subjects aged 6 to 59 years. This nationally representative survey provided the opportunity to estimate the percentage of asthma cases in the U.S. population attributable to skin test positivity, an indirect measurement of atopy (serum IgE was not measured in NHANES III). Data were obtained from NHANES III, a complex survey designed to represent the civilian noninstitutionalized population of the U.S. Questionnaires were adminstered to and medical examinations and laboratory tests conducted on 31,311 individuals age 2 months to 90 years. A subsample of 12,106 subjects consisting of all subjects age 6 to 19 years and a random half-sample of subjects age 20 to 59 years were selected for allergy skin testing. The number of subjects with a valid test and results for all 10 allergens was 10,508. The disease outcome for this analysis was doctor-diagnosed current asthma assessed by questionnaire. The prevalence of asthma in the U.S. population age 6 to 59 years was 5.2%. Among the U.S. population age 6 to 59 years, 56.3% of the asthma cases were attributable to atopy. For selected characteristics, the percentage with asthma was reported as follows, with the percentage of cases attributable to atopy in parentheses: overall, 5.2% (56.3%); ages 6-19 years, 6.4% (55.2%); ages 20-39 years, 4.6% (60.6%); ages 40-59 years, 4.9% (52.1%); males, 4.8% (74.1%); females, 5.5% (43.2%); non-Hispanic whites, 5.3% (54.8%); non-Hispanic blacks, 6.0% (49.3%); Mexican Americans, 3.3% (55.8%); BMI 11.2-18.4 (underweight), 5.0% (61.0%); BMI 18.5-24.9 (normal weight), 5.1% (68.6%); BMI 25.0-29.9 (overweight), 3.7% (45.4%); BMI 30.0-79.6 (obese), 7.5% (37.7%). (data source omitted in sample)
PREVALENCE (PEDIATRIC/ADOLESCENT POPULATION): In 2005, approximately 8.9% (6.5 million) of U.S. children aged under 18 years were reported to have current asthma. (data source omitted in sample)
PREVALENCE (ADOLESCENT POPULATION): The Youth Risk Behavior Surveillance System (YRBSS) monitors priority health-risk behaviors, general health status, and the prevalence of overweight and asthma among youth and young adults. YRBSS includes a national school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education and health agencies. As a component of YRBSS, in 2005, communities participating in the Steps to a HealthierUS Cooperative Agreement Program (Steps Program) also conducted school-based surveys of students in grades 9 through 12 in their program intervention areas. These communities used a modified core questionnaire that asks about dietary behaviors, physical activity, and tobacco use and monitors the prevalence of overweight, diabetes, and asthma. This report summarizes results from surveys of students in 15 Steps communities that conducted surveys in 2005. The reporting period was January to May 2005. The national data set and each community data set were cleaned and edited for inconsistencies. Missing data were not imputed statistically. Of 13,953 completed questionnaires from the national YRBS, 36 failed quality control and were excluded from analysis, leaving 13,917 usable questionnaires. LIFETIME ASTHMA: Across surveys, the overall percentage of students who had ever been told by a doctor or nurse that they had asthma (i.e., lifetime asthma) ranged from 15.5% to 27.9% (median: 20.1%). Prevalence among female students ranged from 11.9% to 25.8% (median: 20.3%), and prevalence among male students ranged from 15.1% to 30.3% (median: 20.4%). CURRENT ASTHMA: The overall percentage of students with lifetime asthma who reported having either (1) asthma but no episode or attack or (2) an asthma episode or attack (i.e., current asthma) during the 12 months preceding the survey ranged from 10.9% to 19.7% (median: 15.9%). Prevalence among female students ranged from 9.4% to 21.5% (median: 16.9%), and prevalence among male students ranged from 10.4% to 18.2% (median: 15.5%). ASTHMA EPISODE OR ATTACK: The overall percentage of students with current asthma who had an asthma episode or attack during the 12 months preceding the survey ranged from 28.4% to 52.4% (median: 37.6%). Prevalence among female students ranged from 37.4% to 48.1% (median: 44.9%), and prevalence among male students ranged from 24.5% to 37.8% (median: 28.4%). (data source omitted in sample)
PREVALENCE (PEDIATRIC POPULATION): The prevalence of childhood asthma in the United States has been reported to range from 6% to 18%. The lack of a gold standard for the diagnosis of pediatric asthma contributes to the variability in rates of childhood asthma. In an effort to overcome the differences in methodology of previous prevalence studies, the International Study of Asthma Allergies in Childhood (ISAAC) was designed to determine the prevalence of childhood asthma by using a standardized and validated methodology. ISAAC has been used in more than 50 countries and more than 100 independent sites. The current study was designed to compare the resource utilization and healthcare costs of children with a diagnosis of asthma, children dispensed asthma medications but without a diagnosis of asthma, and control children. This study was a descriptive, retrospective, cross-sectional analysis conducted during the calendar year of 2001. Patients were identified from an integrated managed-care database (PharMetrics; Watertown, MA), which is a collection of administrative claims from a number of managed-care organizations distributed across the United States. A total of 295,099 children were identified. Overall, an asthma diagnosis (Dx cohort) was recorded in 6.7% of the population, and 4.4% of the children met the criteria for the asthma Rx cohort (prescription for an asthma controller or reliever medication but without an asthma diagnosis) during the study year. The prevalence of physician-diagnosed asthma (Dx cohort) was highest in the 2- to 4-year-olds (7.9%) and lowest in the 13- to 17-year-olds (5.5%). A significant male predominance was noted in the overall Dx and Rx cohorts compared with the control children. 13% and 12% of the 0- to 1-year-olds and 2- to 4-year-olds, respectively, met either the Rx or Dx criteria for asthma compared with 11.2% and 10.1% of the 5- to 12- and 13- to 17-year-olds, respectively. The relative proportion of children identified with asthma by the Rx criteria versus the Dx criteria was greatest in the oldest age group. (data source omitted in sample)
PREVALENCE: This report is one in a set of reports summarizing data from the 2004 National Health Interview Survey (NHIS), a multipurpose health survey conducted by the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC). This report provides national estimates for the U.S. civilian noninstitutionalized population of adults. The NHIS has been an important source of information about health and health care in the U.S. since it was first conducted in 1957. All members of the household 17 years of age and over who are at home at the time of the interview are invited to participate and respond for themselves. For children and adults not available during the interview, information is provided by a knowledgeable adult family member (18 years of age or over) residing in the household. The interviewed sample for 2004 consisted of 36,579 households, which yielded 94,460 persons in 37,466 families. There were 37,388 adults eligible for the Sample Adult questionnaire. Data were collected for 31,326 adults, a conditional response rate of 83.8% (the number of completed Sample Adult interviews divided by the total number of eligible sample adults). The unconditional or final response rate for the Sample Adult Core component was calculated by multiplying the conditional rate by the overall family response rate of 86.5%, yielding a final Sample Adult component response rate of 72.5%. (LIFETIME PREVALENCE) The total number of subjects (in thousands) who had ever been told by a doctor or other health professional that they had asthma was reported as 21,300 (crude rate, 9.9%; age-adjusted rate, 9.9%). The number of cases was reported as follows for selected demographic variables, with the age-adjusted rate in parentheses: males, 8796 (8.5%); females, 12,503 (11.2%); ages 18-44 years, 10,959 (9.9%); ages 45-64 years, 6973 (10.0%); ages 65-74 years, 1893 (10.3%); ages 75 and over, 1474 (9.1%); whites, 17,376 (9.7%); blacks, 2755 (11.2%); Hispanics/Latinos, 2013 (7.9%); less than high school education, 3227 (10.5%); bachelor's degree or higher, 4706 (9.2%); family income less than $20,000, 4554 (12.5%); family income $75,000 or more, 4439 (9.5%); poor, 2260 (13.4%); not poor, 11,200 (9.9%). The prevalence was reported as follows by health insurance coverage. Under age 65 years: private, 11,962 (9.5%); Medicaid, 2081 (17.0%); uninsured, 2963 (8.6%). Age 65 and over: private, 1996 (9.5%); Medicaid and Medicare, 348 (18.0%); Medicare only, 771 (8.6%). (CURRENT PREVALENCE) The total number of subjects (in thousands) who had ever been told they had asthma and still had asthma was reported as 14,358 (crude rate, 6.7%; age-adjusted rate, 6.7%). The number of cases was reported as follows for selected demographic variables, with the age-adjusted rate in parentheses: males, 5148 (5.0%); females, 9210 (8.2%); ages 18-44 years, 7058 (6.4%); ages 45-64 years, 4871 (7.0%); ages 65-74 years, 1368 (7.5%); ages 75 and over, 1061 (6.6%); whites, 11,750 (6.6%); blacks, 1890 (7.7%); Hispanics, 1163 (4.6%); less than high school education, 2386 (7.8%); bachelor's degree or higher, 3053 (5.9%); family income less than $20,000, 3467 (9.6%); family income $75,000 or more, 2838 (6.0%); poor, 1742 (10.3%); not poor, 7209 (6.3%). The prevalence was reported as follows by health insurance coverage. Under age 65 years: private, 7782 (6.2%); Medicaid, 1549 (12.7%); uninsured, 1955 (5.7%). Age 65 and over: private, 1487 (7.1%); Medicaid and Medicare, 224 (11.6%); Medicare only, 542 (6.1%). (data source omitted in sample)
PREVALENCE: This study provided national estimates of asthma prevalence among U.S. adults and analyzed the relative contributions of demographic, geographic, socioeconomic, behavioral, environmental, and health care variables to elevated rates. The National Health Interview Survey (NHIS) is an annual national health survey in which personal interviews are conducted in respondents' homes throughout the year. This study used data collected during the 1998 through 2000 survey years. Between 1997 and 2000, the NHIS included at least 2 questions on asthma each year: "Have you ever been told by a doctor or other health professional that you had…asthma?" (lifetime asthma) and "During the past 12 months, have you had an episode of asthma or asthma attack?" (asthma in the past year). Between 1998 and 2000, 8.9% of adults in the civilian, noninstitutionalized population of the U.S. reported having ever been diagnosed with asthma. Lifetime asthma prevalence did not increase consistently over this 3-year period. The prevalence of lifetime asthma and of asthma in the past year (respectively) were reported as follows: all, 8.9%, 3.4%; non-Hispanic blacks, 9.6%, 3.6%; non-Hispanic whites, 9.2%, 3.5%; Hispanics, 7.2%, 2.9% (Puerto Ricans, 17.0%, 9.2%; Mexican Americans, 7.5%, 3.0%; Mexicans, 3.9%, 1.3%). (data source omitted in sample)
PREVALENCE (PEDIATRIC AND ADOLESCENT POPULATION): This report presents both age-adjusted and unadjusted statistics from the 2004 National Health Interview Survey (NHIS) on selected health measures for children under 18 years of age. The NHIS is a multistage probability sample survey conducted annually by interviewers of the U. S. Census Bureau for the Centers for Disease Control and Prevention's National Center for Health Statistics and is representative of the civilian noninstitutionalized population of the United States. Data are collected for all family members during face-to-face interviews. The interviewed sample for 2004 consisted of 36,579 households, which yielded 94,460 persons in 37,466 families. There were 13,538 children under 18 years of age eligible for the Sample Child questionnaire. Data were collected for 12,424 sample children, a conditional response rate of 91.8%. 9 million U.S. children under 18 years of age (12%) have ever been diagnosed with asthma. As the age increases, the percentage of children ever diagnosed with asthma increases. Boys were more likely than girls to have ever been diagnosed with asthma (15% and 9%). The total number (in thousands) and age-adjusted percent, respectively, of children under age 18 who had ever been told by a doctor or other health professional that they had asthma were reported as follows: total, 8890, 12.2%; males, 5524, 14.8%; females, 3366, 9.4%; age 0 to 4 years, 1454, 7.3%; age 5 to 11 years, 3653, 13.0%; age 12 to 17 years, 3782, 15.2%; white, 6328, 11.3%; black or African American, 1910, 17.2%; Hispanic or Latino, 1423, 10.4%; poor (below the poverty threshold), 1294, 14.1%; near poor (100% to under 200% of the poverty threshold), 1751, 13.3%; not poor (200% or more of the poverty threshold), 4032, 11.6%. The total number (in thousands) and age-adjusted percent, respectively, of children under age 18 who had had an asthma attack in the past 12 months were reported as follows: total, 3975, 5.5%; males, 2497, 6.7%; females, 1478, 4.1%; age 0 to 4 years, 781, 3.9%; age 5 to 11 years, 1710, 6.1%; age 12 to 17 years, 1484, 5.9%; white, 2844, 5.1%; black or African American, 882, 8.0%; Hispanic or Latino, 568, 4.2%; poor, 652, 7.0%; near poor, 774, 5.9%; not poor, 1824, 5.3%. Almost 4 million children (6%) had an asthma attack in the past 12 months. Non-Hispanic black children were more likely than Hispanic children to have had an asthma attack in the past 12 months (8% and 4%). Children in fair or poor health were more than 7 times as likely to have had an asthma attack in the past 12 months as children in excellent or very good health (29% and 4%). ((data source omitted in sample)
PREVALENCE TRENDS: For 1997, 2002, and 2003, respectively, the percentage of U.S. adults (age 18 and older) who had ever been told by a doctor or other health professional that they had asthma ("ever asthma") and who reported having an episode of asthma or an asthma attack in the past 12 months was reported as follows: total (age-adjusted), 3.7%, 3.7%, 3.3%; total (crude), 3.7%, 3.7%, 3.3%; age 18 to 44 years, 4.0%, 4.0%, 3.4% (18 to 24 years, 4.8%, 4.6%, 3.5%; 25 to 44 years, 3.8%, 3.8%, 3.4%); age 45 to 64 years, 3.6%, 3.7%, 3.7% (45 to 54 years, 4.1%, 3.9%, 3.7%; 55 to 64 years, 2.9%, 3.4%, 3.7%); age 65 years and over, 2.7%, 3.0%, 2.3% (65 to 74 years, 3.1%, 3.4%, 2.8%; 75 years and over, 2.2%, 2.4%, 1.7%). For 1997, 2002, and 2003, respectively, the percentage of men with ever asthma who reported having an episode of asthma or an asthma attack in the past 12 months was 2.6%, 2.3%, and 2.0%; for women, the corresponding percentages were 4.7%, 5.0%, and 4.5%. For 1997, 2002, and 2003, respectively, the percentage of adult men versus women with ever asthma who reported having an episode of asthma or an asthma attack in the past 12 months was reported as follows: 18 to 44 years, 2.7% vs 5.3%, 2.5% vs 5.4%, 2.3% vs 4.5%; 45 to 54 years, 2.7% vs 5.4%, 2.1% vs 5.5%, 2.0% vs 5.4%; 55 to 64 years, 1.9% vs 3.9%, 2.4% vs 4.4%, 1.8% (unreliable estimate; relative standard error [RSE] 20%-30%) vs 5.4%; 65 to 74 years, 2.8% vs 3.4%, 2.3% vs 4.4%, 1.6% (unreliable estimate; RSE 20%-30%) vs 3.7%; 75 years and over, 2.0% (unreliable estimate; RSE 20%-30%) vs 2.3%, 1.7% (unreliable estimate; RSE 20%-30%) vs 2.9%, data not shown (unreliable estimate; RSE over 30%) vs 2.3%. For 1997, 2002, and 2003, respectively, the percentage of adults with ever asthma who reported having an episode of asthma or an asthma attack in the past 12 months was reported as follows: white, 3.7%, 3.7%, 3.3%; black/African American, 3.9%, 4.3%, 3.7%; Hispanic/Latino, 2.8%, 2.3%, 2.8%. For 1997, 2002, and 2003, respectively, the percentage of adults with ever asthma who reported having an episode of asthma or an asthma attack in the past 12 months was reported as follows based on poverty status: poor (below the poverty threshold), 5.9%, 5.5%, 5.3%; near poor (100% to less than 200% of the poverty threshold), 4.4%, 3.9%, 4.1%; nonpoor (200% or greater than the poverty threshold), 3.1%, 3.4%, 2.9%. (data source omitted in sample)
PREVALENCE (PEDIATRIC POPULATION): This study examined the demographics of children with asthma who live in nonurban settings. The cross-sectional study included 19,076 children (6 months to 18 years of age) who lived in 146 nonurban communities in the greater Hartford, Connecticut region and who were enrolled in a disease-management program. The goals of Easy Breathing II are to assist clinicians in private practice to improve recognition of asthma and classification of asthma severity, and to develop a systematic, standardized approach to asthma management including the creation of a written asthma treatment plan. 65 clinicians (86%) from 20 practices (74%) agreed to participate. The 19,076 children enrolled in the Easy Breathing II program were younger than those represented in the 2000 U.S. Census. 18% of the children surveyed had a physician-confirmed diagnosis of asthma. Asthma diagnosis in children enrolled in the Easy Breathing II program varied by ethnicity; African American children were 1.72 times as likely and Hispanic children were 1.91 times as likely as Caucasian children to have physician-confirmed asthma. The children with asthma were more likely to be male and at least 5 years of age. 24% of the children in the Easy Breathing II program had newly diagnosed asthma. (data source
omitted in sample)
PREVALENCE (HIGH SCHOOL STUDENTS): To examine self-reported asthma and asthma attacks among U.S. high school students, the Centers for Disease Control and Prevention (CDC) analyzed data from the 2003 national Youth Risk Behavior Survey. This report summarizes the results of that analysis. The 2003 national survey used a three-stage cluster sample design to obtain cross-sectional data representative of public- and private-school students in grades 9-12 in the 50 states and the District of Columbia. The school response rate was 81%, the student response rate was 83%, and the overall response rate was 67%. Students completed an anonymous, self-administered questionnaire that included two questions about asthma. The percentage of high school students reporting lifetime asthma, current asthma, or (among those with current asthma) an asthma episode or attack during the preceding 12 months, respectively, was reported as follows: males, 19.0%, 15.5%, 31.1%; females, 18.7%, 16.8%, 44.5%; whites, 19.3%, 17.0%, 38.7%; blacks, 21.3%, 16.8%, 33.9%; Hispanics, 15.6%, 12.9%, 38.8%; 9th grade, 20.5%, 17.5%, 45.0%; 10th grade, 18.0%, 15.0%, 36.4%; 11th grade, 18.2%, 15.9%, 34.6%; 12th grade, 18.3%, 15.5%, 33.0%; total, 18.9%, 16.1%, 37.9%. In this survey, 18.9% of high school students had been told by a doctor or a nurse that they had asthma, 16.1% had current asthma, and 37.9% of those with current asthma had had an episode of asthma or an asthma attack during the 12 months preceding the survey. (data source omitted in sample)
PREVALENCE (UNCONTROLLED ASTHMA): This analysis characterized changes in asthma control over a 36-month period for managed care enrollees from a number of plans distributed across the U.S. Control was assessed on a resource utilization definition of asthma exacerbations, including asthma-related emergency department visits, asthma-related hospitalizations, oral corticosteroid use, or increased dispensing of short-acting beta-2-agonists. Asthma-related utilization was analyzed over 36 months to determine the pattern of asthma control over time. All data are collected from claims submitted by providers (i.e., physicians, pharmacies, and hospitals) to payers (i.e., managed care organizations) to receive payment for services rendered. The study population was identified from the database for the period 1996 through 2002. Subjects aged 5 to 55 years with asthma were identified by using ICD-9-CM codes 493.0 through 493.9. In all, 63,324 patients were identified who had a diagnosis of asthma and met the 36-month enrollment-utilization criteria. During any quarter of the study, as many as 25% of study patients were considered to have uncontrolled asthma, with about 42% meeting the operational definition in any given 12-month period. Among patients with controlled asthma in year 1, 53% experienced a period of uncontrolled asthma in one or more of the subsequent 8 quarters. Although the risk of loss of control in years 2 and 3 was nearly 4-fold lower for the subjects with initially controlled asthma than the risk for the uncontrolled cohort members, the index event for loss of control in the former group was more likely a claim for an emergency department visit-hospitalization or for an oral corticosteroid dispensing. The uncontrolled cohort experienced an even higher risk of further episodes of uncontrolled asthma, with about 34% to 46% meeting criteria for uncontrolled asthma in each quarter of years 2 and 3. By the end of the 3 years of observation, a minority of the population (27%) was consistently identified as having controlled asthma. The definition of control selected for the purposes of the present research uses a moderately low threshold. In conclusion, about 50% of patients initially identified as having controlled asthma had uncontrolled asthma at some time over the subsequent 2 years, with a noteworthy proportion of these patients having an asthma-related emergency department visit, having a hospitalization, or requiring the use of oral corticosteroids. These results highlight the inability of most asthmatic subjects to continually maintain asthma control and the unpredictability of exacerbations, even in previously controlled patients. (data source omitted in
sample)
PREVALENCE TRENDS: (PAST-YEAR EPISODES) For the period January through September 2004, the percentage of persons of all ages who experienced an asthma episode in the past 12 months was 4.0%, which was higher than, but not significantly different from, the 2003 estimate of 3.9%. For the period 1997 through September 2004, the percentage of persons of all ages who experienced an asthma episode in the past 12 months was reported as follows: 1997, 4.2%; 1998, 3.9%; 1999, 3.9%; 2000, 4.0%; 2001, 4.3%; 2002, 4.3%; 2003, 3.9%; January through September 2004, 4.0%. The percentage of persons of all ages who experienced an asthma episode in the past 12 months decreased from 4.2% in 1997 to 3.9% in 1999, but increased significantly to 4.3% in 2001. The rates then decreased again to 3.9% in 2003. For the period January through September 2004, the percentage of persons who experienced an asthma episode in the past 12 months was estimated as follows by age (males versus females in parentheses): ages 0 to 14 years, 5.0% (7.0% vs 3.5%); ages 15 to 34 years, 3.7% (3.4% vs 4.1%); ages 35 and over, 3.7% (3.0% vs 4.8%). For both sexes combined, the percentage of persons who had an asthma episode in the past 12 months was higher among children under age 15 than among those age 15 and over. For the period January through September 2004, the sex-adjusted percentage of persons who experienced an asthma episode in the past 12 months was estimated as follows by race/ethnicity (ages 0 to 14 years versus 15 years and over): Hispanics, 4% vs 3%; white non-Hispanic, 4.7% vs 3.8%; black non-Hispanic, 7.3% vs 4.3%. (CURRENT PREVALENCE) For the period January through September 2004, 7.2% of persons of all ages currently had asthma, which was higher than, but not significantly different from, the 2003 estimate of 7.1%. The prevalence of current asthma among persons of all ages decreased from 7.6% in 2001 to 7.1% in 2003. For the period January through September 2004, the prevalence of current asthma was estimated as follows (males versus females in parentheses): ages 0 to 14 years, 8.0% (10.0% vs 6.0%); ages 15 to 34 years, 7.0% (6.0% vs 8.5%); ages 35 and over, 7.0% (5.5% vs 8.5%). For the period January through September 2004, the sex-adjusted prevalence of current asthma was estimated as follows by race/ethnicity (ages 0 to 14 years versus 15 years and over): Hispanics, 7.0% vs 4.3%; white non-Hispanic, 7.3% vs 7.3%; black non-Hispanic, 12.0% vs 8.2%. (data source omitted in sample)
PREVALENCE BY TYPE (PEDIATRIC POPULATION): This study examined a nationally representative sample of U.S. children aged 6 to 16 years old and determined whether there are differences in risk factors and measures of severity between children with different asthma phenotypes. Data were obtained from the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988 through 1994 by the National Center for Health Statistics of the Centers for Disease Control and Prevention (CDC). To delineate children who had asthma from those who did not have asthma, the authors used a positive answer to the question, "Has a doctor ever told you that your child has asthma?" After exclusions, the analytic sample consisted of 5244 children who represented about 39.6 million U.S. children. The authors classified 4.8% of children as having atopic asthma, 1.9% as having nonatopic asthma, 3.4% as having resolved asthma, 4.3% as having frequent respiratory symptoms with no asthma diagnosis, and 85.6% as normal. Children with resolved asthma were, in general, more similar to normal children than those with atopic asthma. They did, however, have significantly lower lung function. (data source omitted
in sample)
PREVALENCE: Based on the 2002 National Health Interview Survey sample, it was estimated that 30.8 million Americans, or 110.6 per 1000 persons, had been diagnosed with asthma by a health professional within their lifetime. Between 1997 and 2002, children 5 to 17 years of age have had the highest prevalence rates. In 2002, 140 per 1000 children ages 5 to 17 had been diagnosed with asthma in their lifetime. The number of people who were ever told by a health professional that they had asthma (lifetime prevalence) for 2000, 2001, and 2002, respectively, was reported as follows (with the prevalence rate per 1000 persons in parentheses): all ages, 27,615,006 (100.8), 31,353,657 (113.4), 30,821,125 (110.6); younger than five years, 1,535,639 (78.3), 1,552,713 (78.7), 1,451,929 (73.2); 5 to 17 years, 7,382,614 (140.0), 7,631,820 (144.2), 7,442,217 (140.0); all persons younger than 18 years, 8,918,253 (123.3), 9,184,533 (126.4), 8,894,146 (121.9); 18 to 44 years, 10,676,318 (98.4), 12,795,275 (118.0), 12,453,741 (115.2); 45 to 64 years, 5,266,650 (87.0), 6,507,867 (104.1), 6,836,046 (105.7); 65 years and older, 2,753,785 (84.2), 2,865,982 (87.2), 2,637,162 (79.8); all persons older than 18 years, 18,696,753 (92.7), 22,169,124 (108.8), 21,926,949 (106.5). Females have had consistently higher asthma rates than males. In 2002, females were about 10% more likely than males to ever have been diagnosed with asthma. The difference between sexes was not statistically significant. Blacks are more likely to be diagnosed with asthma over their lifetime. In 2002, the prevalence rate in blacks was 29% higher than the rate in whites. Since 1997 the differences in lifetime asthma prevalence between races have been statistically significant. Over 20 million Americans (6.1 million children) had asthma in 2002: a rate of 71.8 per 1000 population. The highest prevalence rate was seen in those 5 to 17 years of age (91.9 per 1000 population), with rates decreasing with age. Overall, the rate in those under 18 (83.1 per 1000) was significantly greater than those over 18 (67.8 per 1000). In 2002, 8.5 million males and 11.6 million females had asthma. The prevalence rate in females (81 per 1000 persons) was almost 30% greater than the rate in males (62.6 per 1000 persons). However, this pattern was reversed among children. The current asthma prevalence rate for boys aged 0 to 17 years (94.8 per 1000) was over 30% higher than the rate among girls (71.6 per 1000). The difference in rates between sexes was statistically significant in both children and adults. In 2002, the current asthma prevalence rate was 38% higher in blacks than in whites. This difference between races was significant. The highest prevalence rates for whites and blacks were among the 5 to 17 age group. Whites had the lowest prevalence rates in those under 5 and blacks had the lowest in those over 65. Over the past year, the asthma prevalence rate in blacks has increased 8.5%, while decreasing 3.5% in whites. The proportion of attacks that occur within a population at a single point in time is the attack prevalence. In this report, it is the proportion of people who had one or more asthma attacks or episodes in the preceding year. This type of period prevalence estimate measures for active asthma. In 2002, an estimated 11.9 million Americans (4.2 million children under 18) had an asthma attack. This represents 60% of the 20 million people who currently had asthma. The asthma attack rate was 42.7 per 1000 population in 2002. (data source omitted in sample)
PREVALENCE: Asthma is a chronic lung disease caused by inflammation of the lower airways and episodes of airflow obstruction. Asthma episodes or attacks can vary from mild to life-threatening. Data from the 2000 Medical Expenditure Panel Survey (MEPS) show that about 25.3 million people (18.2 million adults aged 18 or older and 7.1 million children 0-17 years) have been told by a physician or other health care provider that they had asthma. Of those who were ever told that they had asthma, 6.5 million adults aged 18 or over and 3.2 million children 0-17 years had an asthma episode or an attack within the 12 months preceding the MEPS interview (active asthma). In 2000 about 3.5% of the U.S. civilian noninstitutionalized population reported having an asthma episode or attack in the last 12 months (males, 2.8%; females, 4.1%). Children were more likely (4.4%) than adults (3.1%) to have active asthma. Among children, males were more likely (5.4%) than females (3.4%) to have active asthma. For adults, females were more than twice as likely as males to have active asthma (4.3% compared to 1.9%). (data source omitted in sample)
PREVALENCE TRENDS: Between 1997 and 1999, the lifetime asthma prevalence rate in the U.S. decreased by about 6% (96.6 per 1000 persons in 1997, to 90.9 per 1000 persons in 1999) but increased again by 25% to 2001 (113.4 per 1000 persons in 2001). As with lifetime asthma prevalence, the asthma attack rate decreased by 7.4% from 1997 to 1999 (41.8 per 1000 population in 1997, to 38.6 per 1000 population in 1999) but then increased significantly by 10% (42.6 per 1000 population) in 2002. Results for the first half of 2003 indicate an asthma attack rate of 40.1 per 1000 population. Despite a recent increase in lifetime asthma prevalence, estimates from the National Hospital Discharge Survey suggest a decline in the number of hospital discharges for asthma from 1988 to 2000. Similarly, mortality rates declined over the same time period. During the 1980s and early 1990s asthma prevalence trended upward in the U.S. followed by a brief, but not sustained, decline from 1997 to 1999. The 2001 NHIS data suggest that there has been a net increase in lifetime asthma prevalence in the U.S. since 1997. Thus, any conclusions about the end of the asthma epidemic in the U.S. are premature. (data source omitted in sample)
PREVALENCE: Of the 17 million Americans with asthma, 10 million are thought to have allergic asthma. (data source omitted in sample)
PREVALENCE: To assess asthma prevalence and asthma-control characteristics among racial/ethnic populations, the Centers for Disease Control and Prevention analyzed 2002 data from the Behavioral Risk Factor Surveillance System (BRFSS). BRFSS is a state-based, random-digit-dialed telephone survey of the noninstitutionalized, civilian U.S. population aged 18 years and older. In 2002, the median response rate for all 54 reporting areas was 58.3%. Asthma characteristics for white non-Hispanics, black non-Hispanics, Asian non-Hispanics, and Hispanics, respectively, were reported as follows for 2002: current prevalence, 7.6%, 9.3%, 2.9%, 5.0%; emergency department visits, 14.5%, 37.2%, 18.8%, 26.0%; urgent visits, 25.8%, 35.9%, 17.1%, 36.9%; routine visits, 52.6%, 62.9%, 50.9%, 51.4%; use of medication(s), 70.0%, 68.0%, 63.2%, 67.0%. Asthma characteristics for participants of all races/ethnicities were reported as follows: current prevalence, 7.2%; emergency department visits, 18.4%; urgent visits, 28.5%; routine visits, 53.9%; use of medication(s), 69.3%. Among the estimated 16 million (7.5%) U.S. adults with asthma, self-reported current asthma prevalence among racial/ethnic minority populations ranged from 3.1% to 14.5%, compared with 7.6% among whites. Among all U.S. adults, the prevalence of lifetime and current asthma was 11.8% and 7.5%, respectively. (data source omitted in sample)
PREVALENCE: Approximately 3.5 million American adults aged 35 to 64 years have symptomatic asthma. (data source omitted in sample)
PREVALENCE (PEDIATRIC POPULATION): This population-based survey measured the prevalence of asthma-like symptoms (wheezing and cough) among children with and without a physician diagnosis of asthma. It compared the functional consequences of health care use of children with current wheezing symptoms with no physician diagnosis with those of two groups: (1) children with physician-diagnosed asthma with current asthma-like symptoms and (2) asymptomatic children who reported never having any asthma-like symptoms or diagnosis. The target population was enumerated from 1999 to 2000 enrollment records kept by the North Carolina Department of Public Instruction and included 565 public schools with 192,248 children in the seventh and eighth grades. The study population of 122,829 was ethnically diverse. The prevalence of ever physician-diagnosed asthma was 16%: 10% had current wheezing symptoms (in the last 12 months), 1% had current cough, and 5% had no current symptoms. Combining diagnosed asthmatics with current symptoms (11%), diagnosed asthmatics without current symptoms (5%), and children with undiagnosed current wheezing (17%) gives a population-based prevalence of 33% for ever having asthma or asthma-like symptoms. More than one-fourth (28%) of the children reported current asthma-like symptoms or asthma. These estimates of wheezing prevalence based on 122,829 children agree well with the estimates reported in the worldwide ISAAC survey from other industrialized countries. The present estimates of wheezing during the day (at rest) in the last 12 months were 23% (written questionnaire) and 13% (video questionnaire), which are similar to the estimates reported in the worldwide study of 20% to 25% (written) and about 13% (video) for the U.S. ISAAC sites. The current estimate of 11% of children in the population with physician-diagnosed current asthma is comparable to but somewhat higher than the most recent Third National Health and Nutrition Examination Survey (NHANES III) estimate of 6.7% with physician-diagnosed asthma in children aged 2 to 16 years. The National Health Interview Survey on Child Health reports an asthma estimate considerably lower (4.9%) for children aged 6 to 18 years. (data source omitted in sample)
PREVALENCE: To provide prevalence data for state and local health department asthma programs, the Behavioral Risk Factor Surveillance System (BRFSS) collects data each year from the 50 states, the District of Columbia, and three U.S. territories. In 2001, an estimated 31.3 million persons reported ever having asthma diagnosed, and 20.3 million persons currently had asthma. Each year, about 14 million days of school absences and about 100 million days of restricted activity are attributed to asthma. The overall prevalence of lifetime asthma among adults was 11.0%. During 2001, an estimated 15.1 million adults in the U.S. and the District of Columbia had current asthma. Current asthma was higher among persons who were multiple race/non-Hispanic (12.2%), followed by non-Hispanic blacks (8.5%), non-Hispanic whites (7.2%), other race/non-Hispanic (5.9%), and Hispanics (5.7%). (data source omitted in sample)
PREVALENCE: For 1997 versus 1999, the estimated annual prevalence per 1000 population of an episode of asthma during the previous 12 months by race, sex, and age was reported as follows: Caucasian, 40.5 vs 37.6; African-American, 45.4 vs 38.9; male, 33.0 vs 31.6; female, 47.9 vs 44.5; ages 0 to 4 years, 41.2 vs 42.1; ages 5 to 14 years, 60.0 vs 56.4; ages 13 to 34 years, 44.2 vs 42.2; ages 35 to 64 years, 37.0 vs 33.4 years; ages 65 years and older, 27.3 vs 22.1. This data was taken from the National Health Interview Survey. Self-reported prevalence of asthma in the U.S. may have peaked in 1995 at 55.2 per 1000 as estimated from annual National Health Interview Surveys. A change in collection of data in 1997 has limited interpretation of trends in prevalence. Previously, interviewers asked participants in the national probability sample whether they had had asthma during the previous 12 months. In 1997 they asked "Has a doctor or other health professional ever told you that you had asthma? During the past 12 months have you had an episode of asthma or an asthma attack?" Prevalence of asthma increased from 31.4 per 1000 general population in 1980 to 55.2 in 1995 and decreased slightly to 54.6 in 1996. Self-reported lifetime prevalence in 1997 was 96.6 per 1000 population, but current physician-diagnosed prevalence was 40.7 per 1000. Current prevalence decreased to 38.4 in 1999. Prevalence has been higher among blacks than whites, higher among females than males, and highest at 5 to 14 years of age. There had been little change in prevalence of acute asthma among children and adolescents from 1997 through 2000. (data source omitted in sample)
DISTRIBUTION BY SEVERITY: This study characterized the distribution of asthma burden using a National Asthma Education and Prevention Program (NAEPP)-based classification scheme within the U.S. population. The data for this study come from a national probability sample of adult patients and parents of children with current asthma. Interviews were conducted by trained interviewers in 42,022 households with telephones in the U.S. One or more persons who met the criteria for current asthma were identified in 3273 of the 42,022 households (7.8%) in which a screening interview was completed. Interviews were completed with 2509 of the 3273 selected asthma patients or parents (76.7%). Patient screening and interviews were conducted between May 21 and July 19, 1998. The mean age of the adult population with asthma in the sample was 40.5 years, with a high proportion being female (69%). On the basis of the severity criteria derived from the NAEPP guidelines, only a minority (7.3%) of individuals were classified as having a global asthma burden consistent with mild intermittent disease; 15.4% were classified as having mild persistent disease, and the large majority (77.3%) were classified as having moderate to severe disease. The distribution of asthma burden was influenced by how asthma symptoms were measured. The percentage of subjects reporting mild intermittent, mild persistent, and moderate/severe persistent asthma (respectively) was reported as follows based on selected measures of symptom burden: short-term burden, 44%, 21%, 36% (day, 55%, 26%, 19%; night, 62%, 10%, 28%); long-term symptoms, 46%, 20%, 34% (attacks, 61%, 16%, 24%; long-term symptoms, 64%, 16%, 20%); functional impact, 11%, 19%, 70% (physical, 16%, 21%, 64%; social, 40%, 20%, 40%; nocturnal, 42%, 20%, 37%). (data source omitted in sample)
PEDIATRIC PREVALENCE: This analysis used data from 1980 through the most recent year for which data were available from four National Center for Health Statistics (NCHS) data systems: the National Health Interview Survey (NHIS; in 1997 this survey was redesigned to improve data quality, simplify the survey, and reduce the questionnaire length), the National Ambulatory Medical Care Survey (NAMCS), the National Hospital Discharge Survey (NHDS), and the Mortality Component of the National Vital Statistics System. A fifth NCHS data set, the National Hospital Ambulatory Medical Care Survey (NHAMCS), provided data on ambulatory care in hospitals beginning in 1992. Children aged 0 to 17 years were included, and the sample from each data source was stratified by age group (0 to 4 years, 5 to 10 years, and 11 to 17 years) and by race/ethnicity when possible (white non-Hispanic, black non-Hispanic, and Hispanic). The average annual prevalence of asthma (per 1000) for 1985 to 1986 was reported as follows: overall prevalence, 49.4; white non-Hispanics, 51.0; black non-Hispanics, 59.8; Hispanics, 31.5; 0 to 4 years old, 31.9; 5 to 10 years old, 54.5; 11 to 17 years old, 58.0. The average annual prevalence of asthma (per 1000) for 1990 to 1991 was reported as follows: overall prevalence, 60.1; white non-Hispanics, 59.6; black non-Hispanics, 72.6; Hispanics, 51.2; 0 to 4 years old, 43.0; 5 to 10 years old, 62.7; 11 to 17 years old, 71.4. The average annual prevalence of asthma (per 1000) for 1995 to 1996 was reported as follows: overall prevalence, 68.6; white non-Hispanics, 65.3; black non-Hispanics, 82.1; Hispanics, 76.1; 0 to 4 years old, 50.3; 5 to 10 years old, 74.3; 11 to 17 years old, 77.4. For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 1997 as follows: overall prevalence, 54.4; white non-Hispanics, 52.2; black non-Hispanics, 67.5; Hispanics, 51.3; 0 to 4 years old, 41.2; 5 to 10 years old, 58.5; 11 to 17 years old, 60.4. For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 1998 as follows: overall prevalence, 53.1; white non-Hispanics, 52.1; black non-Hispanics, 68.1; Hispanics, 47.4; 0 to 4 years old, 46.5; 5 to 10 years old, 53.0; 11 to 17 years old, 58.0. For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 1999 as follows: overall prevalence, 52.7; white non-Hispanics, 49.9; black non-Hispanics, 74.1; Hispanics, 44.5; 0 to 4 years old, 42.1; 5 to 10 years old, 57.2; 11 to 17 years old, 56.2. For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 2000 as follows: overall prevalence, 55.3; white non-Hispanics, 53.4; black non-Hispanics, 76.8; Hispanics, 42.1; 0 to 4 years old, 43.5; 5 to 10 years old, 57.5; 11 to 17 years old, 61.5. Asthma prevalence among 0- to 17-year-old children increased from 36 per 1000 children to 75 per 1000 from 1980 to 1995 but then decreased 17% to 62 per 1000 children in 1996. The 1997 estimate of childhood asthma attack prevalence from the redesigned questionnaire, 54 per 1000 children, and subsequent estimates cannot be compared directly with previous estimates and should be considered the first point of a new trend. Because the redesigned asthma questions measure asthma attack prevalence (individuals who had previously received a diagnosis of asthma and who had 1 or more asthma attacks in the past 12 months) as opposed to asthma prevalence in the past 12 months, it is not surprising that the post-1997 estimates are lower than previous estimates. Asthma attack prevalence from 1997 to 2000 remained level with no statistically significant difference between estimates during this time period. In 2000, black non-Hispanic children had an asthma attack prevalence rate 44% higher than that of white non-Hispanic children. From 1985/1986 to 1995/1996, asthma prevalence increased dramatically among Hispanic children. However, from 1997 to 2000, asthma attack prevalence among Hispanic children remained below that for white non-Hispanic children. Within the 3 pediatric age groups, prevalence increased over time. Children aged 0 to 4 years had the most rapid growth in asthma prevalence from 1980/1981 to 1995/1996. From 1997 to 2000, asthma attack prevalence remained fairly level among all age groups. (data source omitted in sample)
PREVALENCE (PEDIATRIC POPULATION): The authors used a nationally representative sample to estimate the strength of the association between low birth weight (LBW) and asthma (relative risk) as well s the magnitude of population-wide impact of LBW on the number of children with asthma (attributable risk). Data from the 1988 National Maternal-Infant Health Survey and the 1991 Longitudinal Follow-Up Survey were analyzed for this study. Standard limits for moderately low birth weight (MLBW) (1500 to 2499 g) and very low birth weight (VLBW) (under 1500 g) were used to categorize children. In this nationally representative, longitudinal sample of 3-year-olds, the prevalence of asthma was 7.1%. Asthma prevalence was 21.9% among VLBW children and 10.9% among MLBW children, compared with 6.7% among children with normal birth weight. (data source omitted in sample)
PREVALENCE: The authors compared predictors of asthma using two different criteria to identify cases: maternal reports and medical records. Data were extracted from the 1988 National Maternal and Infant Health Survey (NMIHS) and its companion 1991 Longitudinal Follow-up (LF). Estimates of asthma prevalence differ substantially depending on which reporting source is used. Weighted to national levels, the prevalence estimates for asthma in the sample were 7.7% based on medical records or 10.0% based on maternal reports. Restricting the definition of "cases" to those for whom both the mother and medical provider mention asthma yields a prevalence of 4.1%; broadening the definition to include any child for whom either the mother or medical provider reported the condition yields a prevalence of 13.6%. (data source
omitted in sample)
PREVALENCE: The authors initially evaluated U.S. college freshmen for evidence of asthma and allergic rhinitis using personal interviews, physical examination, laboratory tests, and allergy skin tests. These students were evaluated again by detailed questionnaires at intervals of 3, 7, and 23 years. For the 23-year follow-up study, the authors present data on 738 individuals (mean age at follow-up, 40 years) who were skin tested as freshmen and who completed the 23-year follow-up questionnaire. In the initial study, the frequency of asthma was 5.3%. In the 3-year follow-up study, the cumulative prevalence increased to nearly 6%. The 7-year follow-up study was of particular significance because it showed the risk of developing asthma to be significantly increased in those individuals with previous allergic rhinitis (seasonal or nonseasonal) when compared with controls (6.0% versus 1.3%). The results of the 23-year follow-up study demonstrated that the prevalence of asthma continues to increase as the individuals become older. (data source omitted in sample)
PEDIATRIC PREVALENCE: According to the NHIS, 1.4% of U.S. children younger than age 18 (996,000 children nationally) experienced some degree of disability due to asthma in 1994 to 1995. The degree of disability ranged from children who were unable to engage in school or play activities (0.2% of all children) to those who were limited in the amount or kind of school or play (0.5% of all children) and those who were able to engage in their main activity but were limited in other activities such as after-school sports (0.7% of all children). Electronic data from the NHIS needed to estimate the prevalence of disabling asthma (DA) first became available in 1969 and continued through 1995. Over this 26-year period, the prevalence of DA increased 232%, from 431 to 1433 per 100,000. During this same period, the prevalence of disability due to causes other than asthma increased 113%, from 2249 to 4800 per 100,000. Hence, prevalence of DA has grown at a much higher rate than prevalence of disability due to other childhood chronic conditions. (data source omitted in sample)
TRENDS BY SEVERITY: Between 1990 to 1992 and 1993 to 1994, the estimated average annual number of persons aged 0 to 4, 5 to 14, and 15 to 34 years with self-reported asthma increased by 47%, 18%, and 22%, respectively, based on the National Health Interview Survey. However, during the same periods, the estimated average annual number of asthma hospitalizations for these age groups decreased by 13%, 8%, and 5%, respectively, based on the National Hospital Discharge Survey. (data source omitted in sample)
PREVALENCE: A total of 4581 participants were seen in the Cardiovascular Health Study (CHS) clinics during the year 6 follow-up examination between May 1993 and June 1994, providing comprehensive measures of cardiovascular disease and risk factors from a representative sample of elderly persons from four U.S. communities. 4% of all CHS participants reported current (definite) asthma that had been confirmed by a physician. An additional 4% reported at least one attack of wheezing with dyspnea or chest tightness during the previous year (probable asthma), and an additional 11% reported wheezing brought on by various exposures (possible asthma). Not included in the definite asthma category are 145 participants who reported a history of asthma but stated that they do not still have asthma. (data source
omitted in sample)
PREVALENCE: Estimates of the prevalence of current childhood asthma in the U.S. range from 4.3% to 6.7%, with evidence to suggest recent increases. A cross-sectional survey was conducted of parents of kindergarten children in Chicago to estimate the prevalence of diagnosed asthma and asthma symptoms. About 80% of the children are low-income. The study was conducted in mid-June 1996, on the day of kindergarten "graduation." Doctor-diagnosed asthma was reported by the respondent in 10.8% of the sample, and 11.5% responded "yes" to the question, "In the past year, has your child had what you thought was asthma?" 16% of the respondents reported that their child had wheezed in the past year, 12.3% had exercise-induced wheezing, and 34% reported a dry cough at night, the most commonly reported symptom. The data help confirm the work of other researchers who studied children ages 0 through 17 living in the Bronx, New York and found the prevalence of asthma to be 14.3% and the prevalence of active asthma (within the last 12 months) to be 8.6%. Only a few studies have examined the prevalence of undiagnosed asthma in U.S. inner-city areas. One group studied African American grammar school children in Detroit, grades 3 through 5, and found that 14.3% had possible undiagnosed asthma based on either symptoms or bronchial hyperresponsiveness. A study of Hispanic 9- to 12-year-olds in San Diego estimated the prevalence of respiratory symptoms indicating possible asthma to be 13.5%. The Bronx study cited above described wheezing without an asthma diagnosis in 4.2% of the children aged 0 to 17. (data source omitted in sample)
PREVALENCE: In 1998, asthma affected an estimated 17,299,000 persons in the U.S. The state with the largest estimated number of persons with asthma was California (2,268,300), followed by New York (1,236,200) and Texas (1,175,100). State-specific prevalence rates ranged from 5.8% to 7.2%. (data source
omitted in sample)
PREVALENCE: According to the National Health Interview Survey (1995), the estimated prevalence rate of asthma per 1000 persons was reported as follows: all ages, 56.8 (14.9 million cases); under 18 years, 74.9 (5.3 million cases); 18 to 44 years, 51.6 (5.6 million cases); under 45 years, 60.8 (10.9 million cases); 45 to 64 years, 53.3 (2.8 million cases); 65 years and over, 39.8 (1.3 million cases); 65 to 74 years, 45.8 (845,000 cases); 75 years and over, 31.3 (407,000 cases). The estimated prevalence rate per 1000 persons was reported as follows for males versus females: under 45 years, 60.7 (5.4 million cases) vs 61.0 (5.4 million cases); 45 to 64 years, 31.4 (785,000 cases) vs 73.6 (2.0 million cases); 65 years and over, 36.2 (476,000 cases) vs 42.3 (776,000 cases); 65 to 74 years, 47.8 (393,000 cases) vs 44.3 (453,000 cases); 75 years and over, 16.9 (unreliable data) (83,000 cases) vs 40.0 (324,000 cases). (data source omitted in sample)
PREVALENCE: Estimated average annual rates (per 1000 population; age-adjusted to the 1970 U.S. population) of self-reported asthma during the preceding 12 months from the National Health Interview Survey were reported as follows (1987 to 1989, 1990 to 1992, and 1993 to 1994, respectively): 42.9, 46.6, 53.8. The corresponding rates by race (also age-adjusted) were reported as follows: white, 41.1, 44.7, 50.8; black, 51.7, 52.2, 57.8; other, (unreliable for 1987-89), 39.7, 48.6. The corresponding rates by gender (also age-adjusted) were reported as follows (male vs female): 43.0 vs 42.3, 45.3 vs 47.5, 51.1 vs 56.2. The corresponding rates by age group (not age-adjusted) were reported as follows: age 0 to 4 years, 33.9, 46.1, 57.8; age 5 to 14 years, 60.7, 65.9, 74.4; age 15 to 34 years, 40.1, 41.7, 51.8; age 35 to 64 years, 36.8, 42.3, 44.6; age 65 years and older, 42.1, 36.4, 44.6. By 1993 to 1994, an estimated 13.7 million persons reported asthma during the preceding 12 months. (data source omitted in sample)
PREVALENCE: Asthma is the most common chronic disease of childhood, affecting an estimated 4.8 million children in the U.S. (data source
omitted in sample)
PREVALENCE: In the U.S., 14 to 15 million people have asthma. Although the onset of asthma may occur at any age, more than 80% of cases develop in people younger than 45 years of age. About 70% of people with asthma have mild disease, whereas 20% and 10% have moderate and severe disease, respectively. (data source omitted in sample)
SYMPTOM RESOLUTION: Many follow-up studies have shown that childhood airway hyperresponsiveness tends to diminish or disappear with age and that about 50% of children with asthma will have outgrown their disease by the time they reach adulthood. (data source omitted in sample)
PREVALENCE: Because of the difficulty in precisely defining asthma, true incidence and prevalence are unknown, but an approximate prevalence of 20% in elderly people has been reported. However, another study has reported an incidence of asthma of over 40% in an elderly population attending day hospital or living in welfare homes. (data source omitted in sample)
PEDIATRIC PREVALENCE (WHEEZING): This study examined the natural history of wheezing in the first 6 years of life. The children were enrolled as newborns between May 1980 and October 1984 in the Tucson Children's Respiratory Study. Follow-up data at both 3 and 6 years of age were available for 826 children. Children were assigned to four categories according to their history of wheezing: those who had no recorded lower respiratory tract (LRT) illness with wheezing during the first 3 years of life and had no wheezing at age 6 (never had wheezing); those with at least one LRT illness with wheezing during the first 3 years of life but no wheezing at age 6 (transient early wheezing); those who had no LRT illness with wheezing during the first 3 years of life but who had wheezing at age 6 (wheezing of late onset); and those who had at least one LRT illness with wheezing in the first 3 years of life and had wheezing at age 6 (persistent wheezing). A total of 425 children (51.5%) were classified as never having wheezed, 164 (19.9%) as having had transient early wheezing, 124 (15.0%) as having wheezing of late onset, and 113 (13.7%) as having persistent wheezing. (data source omitted in sample)
|
WORLDWIDE: In phase I of the International Study of Asthma and Allergies in Childhood (ISAAC), children aged 13-14 years were studied in 155 centers in 56 countries and children aged 6-7 years were studied in 91 centers in 38 countries. Up to 20-fold variations in the prevalence of “current wheeze” (in the last 12 months) were observed between centers worldwide (range 1.8% to 36.7%), with a 7-fold variation observed between the 10th and 90th percentiles (4.4%, 30.9%). Phase III has involved repeating the phase I survey after 5-10 years to examine time trends in the prevalence of asthma, allergic rhinoconjunctivitis and eczema in centers and countries that participated in phase I. Phase III was conducted following as precisely as possible the methods used in phase I. It included two groups of centers: (1) Group A are centers that previously completed phase I according to the ISAAC phase I protocol, including centers for which the phase I data were submitted too late for inclusion in the first worldwide publications but were of the required standard; (2) Group B are centers from around the world that did not participate in phase I but participated in phase III as new centers. The findings reported here are of considerable interest. First, they show that in most high prevalence countries, particularly the English language countries, the rise in the prevalence of asthma symptoms has peaked and may even have begun to decline. This is consistent with the findings of other recent studies in children and in adults. There are some exceptions to this trend, but of the European and English language countries which showed a relatively high prevalence in phase I, only Germany and Finland have shown significant increases in symptom prevalence in phase III. The increases for North America are due to increases in Barbados (where the phase I data were too late for inclusion in the phase I paper); the one U.S. center showed a small decline in symptom prevalence consistent with the findings for other English language countries. Second, a number of countries that had high or intermediate levels of symptom prevalence in phase I have shown significant increases in prevalence in phase III; these include Latin American countries such as Costa Rica, Panama, Mexico, Argentina and Chile, and Eastern European countries such as the Ukraine and Romania. Other countries to show significant increases in symptom prevalence included Barbados, Tunisia, Morocco and Algeria. Third, with the exception of India, all of the countries with very low symptom prevalence rates in phase I reported increases in prevalence in phase III, although only the increases for Indonesia and China were statistically significant. Finally, virtually all countries, irrespective of the level of symptom prevalence, reported increases in lifetime asthma prevalence between phases I and III. In fact, the increases were most marked in those countries with the highest mean prevalence between phase I and phase III, despite the fact that many of these countries reported declines in the prevalence of asthma symptoms between phase I and phase III. (data
source omitted in sample)
WORLDWIDE: In 1989 the Global Initiative for Asthma (GINA) program was initiated with the U.S. National Heart, Lung, and Blood Institute, NIH, and WHO in an effort to raise awareness among public health and government officials, health care workers, and the general public that asthma was on the rise. The GINA program recommends a management program based on the best available scientific evidence to allow doctors to provide effective medical care for asthma tailored to local health care systems and resources. Clinical asthma refers to "clinically important" or severe asthma. This study avoided the use of doctor-diagnosed asthma, or asthma attacks, or of asthma medication use due to the marked variation in the recognition and presentation to a doctor by an individual with recurrent wheezing episodes, and the considerable differences in diagnostic labeling and treatment by doctors between populations. As a result, the prevalence rates for clinical asthma reported here represent a conservative estimate. Asthma is one of the most common chronic diseases in the world. It is estimated that around 300 million people in the world currently have asthma. Considerably higher estimates can be obtained with less conservative criteria for the diagnosis of clinical asthma. For selected countries, the proportion of the population with clinical asthma was reported as follows: Scotland, 18.4%; Wales, 16.8%; England, 15.3%; Australia, 14.7%; Republic of Ireland, 14.6%; Canada, 14.1%; Brazil, 11.4%; U.S., 10.9%; Turkey, 7.4%; Germany, 6.9%; France, 6.8%; Japan, 6.7%; Spain, 5.7%; Saudi Arabia, 5.6%; Argentina, 5.5%; Singapore, 4.9%; Italy, 4.5%. For selected regions (total population in parentheses), the number of persons with asthma and the mean prevalence rate of clinical asthma, respectively, were reported as follows: Scandinavia/Baltic States (70.2 million), 3.4 million, 4.9%; Western Europe (290.8 million), 17.2 million, 5.9%; Russia and Former Socialist Republics of Eastern Europe (264.0 million), 9.8 million, 3.7%; Middle East (177.5 million), 10.3 million, 5.8%; Central Asia and Pakistan (224.7 million), 9.7 million, 4.3%; Southern Asia (1210.0 million), 42.2 million, 3.5%; China/Taiwan/Mongolia (1324.1 million), 27.8 million, 2.1%; Northeast Asia (196.8 million), 11.4 million, 5.8%; Southeast Asia (529.3 million), 17.5 million, 3.3%; Oceania (30.7 million), 4.5 million, 14.6%; North America (316.9 million), 35.5 million, 11.2%; Central America (137.3 million), 5.2 million, 3.8%; Caribbean (32.6 million), 3.4 million, 10.4%; South America (350.4 million), 34.7 million, 9.9%; North Africa (196.5 million), 7.7 million, 3.9%; West Africa (239.5 million), 13.7 million, 5.7%; East Africa (230.2 million), 10.1 million, 4.4%; Southern Africa (186.3 million), 15.1 million, 8.1%. The rate of asthma increases as communities adopt western lifestyles and become urbanized. With the projected increase in the proportion of the world's population that is urban from 45% to 59% in 2025, there is likely to be a marked increase in the number of asthmatics worldwide over the next two decades. It is estimated that there may be an additional 100 million persons with asthma by 2025. (data source
omitted in sample)
WORLDWIDE: Asthma is one of the most common chronic diseases in the world. It is estimated that about 300 million people in the world currently have asthma. Considerably higher estimates can be obtained with less conservative criteria for the diagnosis of clinical asthma. The rate of asthma increases as communities adopt western lifestyles and become urbanized. With the projected increase in the proportion of the world's population that is urban from 45% to 59% in 2025, there is likely to be a marked increase in the number of asthmatics worldwide over the next two decades. It is estimated that there may be an additional 100 million persons with asthma by 2025. In many areas of the world persons with asthma do not have access to basic asthma medications or medical care. The prevalence of clinical asthma for selected countries was reported as follows: England, 15.3%; Brazil, 11.4%; U.S., 10.9%; Germany, 6.9%; France, 6.8%; Japan, 6.7%; Hong Kong, 6.2%; Singapore, 4.9%; Portugal, 4.8%; Italy, 4.5%; India, 3.0%; Russia, 2.2%; China, 2.1%; Greece, 1.9%. The true prevalence of asthma is difficult to determine due to the lack of a single objective diagnostic test, different methods of classification of the condition, differing interpretation of symptoms in different countries, as well as the uncertain influence of increasing public and professional awareness of asthma. In this report an arbitrary figure of 50% of the prevalence of "current wheezing" in children (self-reported wheezing in the previous 12-month period in 13- to 14-year-old children) has been used as the prevalence of "clinical asthma." (data source omitted in sample)
WORLDWIDE (WITH INDIA): For selected European Community Respiratory Health Survey centers, the prevalence of asthma attack, use of asthma medicine, nasal allergy, and diagnosed asthma (respectively) was reported as follows: Mumbai (India), 2.6%, 2.8%, 10.1%, 3.5%; Goteborg (Sweden), 3.1%, 4.8%, 22.2%, 5.8%; Hamburg (Germany), 3.0%, 3.4%, 23.0%, 4.4%; Cambridge (UK), 5.7%, 6.8%, 29.2%, 8.4%; Paris (France), 4.3%, 3.2%, 30.3%, 5.1%; Barcelona (Spain), 2.1%, 2.2%, 13.1%, 3.1%; Athens (Greece), 2.4%, 2.2%, 18.4%, 2.9%; Wellington (New Zealand), 8.6%, 9.8%, 36.6%, 11.3%; Melbourne (Australia), 9.7%, 9.3%, 40.9%, 11.9%; Portland (U.S.), 5.8%, 4.8%, 39.4%, 7.1%; Algiers (Algeria), 2.4%, 2.5%, 9.5%, 3.0%. In one study, the European Community Respiratory Health Survey (ECRHS) surveillance tools were applied to a randomly selected sample of Mumbai (formerly Bombay), India residents in 1992 through 1995. From a metropolitan population of over 10 million, a 1-in-10 random sample was taken from electoral rolls in a socially diverse residential district, and asthma symptoms were examined in adults aged 20 to 44 years. 2313 subjects were interviewed. The prevalence of diagnosed asthma in in the previous 12 months was reported as follows: all ages (20 to 45 years), 3.5%; ages 20 to 24 years, 5.3%; ages 25 to 29 years, 3.5%; ages 30 to 34 years, 2.8%; ages 35 to 39 years, 3.2%; ages 40 to 45 years, 4.3%. The asthma prevalence in this Mumbai sample was 3.5% based on reported physician diagnosis, but 9% to 12% when symptomatic subjects without diagnosis were included. These figures exceed the 2.78% prevalence of asthma in adults aged 30 to 49 years seen in the only other large survey of asthma in India. (data source omitted in sample)
WORLDWIDE (BRITTLE ASTHMA): The term "brittle asthma" was first used in 1977 to describe patients with asthma who maintained a wide variation in peak expiratory flow (PEF) despite high doses of inhaled steroids. The present authors suggest the following classification. Type 1 brittle asthma is characterized by a maintained wide PEF variability (over 40% diurnal variation for over 50% of the time over a period of at least 150 days) despite considerable medical therapy including a dose of inhaled steroids of at least 1500 mcg of beclomethasone (or equivalent). Type 2 brittle asthma is characterized by sudden acute attacks occurring in less than 3 hours without an obvious trigger on a background of apparent normal airway function or well controlled asthma. Little is known about the incidence or prevalence of brittle asthma, partly because of the problems with definition. There is no doubt that it is rare but it is not possible to estimate the prevalence from any of the studies of "near miss" asthma. The West Midlands Brittle Asthma Register has identified 76 patients with type 1 or 2 brittle asthma within an approximate asthma population of 300,000. A conservative estimate of the numbers not yet identified by the register would be around 150, giving an overall prevalence for brittle asthma of 0.05% of all asthmatic patients. The type 1 patients is more likely to be female (female-to-male ratio, 2.5 to 1), most patients being aged between 18 and 55 years, whereas in patients with type 2 brittle asthma there appears to be no sex difference. There is little information available regarding peak flow variability prior to death from asthma in children. (data source omitted in sample)
WORLDWIDE (PEDIATRIC POPULATION): The authors describe the results of the worldwide International Study of Asthma and Allergies in Childhood (ISAAC) study of the prevalence of symptoms of asthma. Included in this first worldwide analysis are a total of 155 centers for the 13- to 14-year-old age group and 91 centers for the 6- to 7-year-old age group. For each center included, the data were received and verified by the ISAAC International Data Center by June 30, 1996. The data-checking processes and a detailed report on study design and methods were completed by November 24, 1997. The first center began its survey in 1991, but most centers undertook the data collection in 1994 and 1995. Subjects aged 13 to 14 years were selected because they were able to self-complete the written and video questionnaires. The younger age group, 6 to 7 years, was chosen as this is the youngest age when children are usually at school. The recommended sample size was 3000 to ensure good prevalence estimates for severe asthma. Centers with limited resources or small populations were included in the prevalence comparisons, providing that the sample size was at least 1000 per age group. The requirements for analysis were met by 156 collaborating centers in 56 countries, with a total of 721,601 participating children. The prevalence of children aged 13 to 14 years whose sleep had been disturbed by wheezing during the last 12 months and the prevalence of those who had ever had asthma, respectively, were reported as follows by region: global total, 1.7%, 11.3%; Africa, 3.1%, 10.2%; Asia-Pacific, 0.6%, 9.4%; Eastern Mediterranean, 2.6%, 10.7%; Latin America, 2.6%, 13.4%; North America, 3.4%, 16.5%; Northern and Eastern Europe, 0.6%, 4.4%; Oceania, 3.1%, 25.9%; South-east Asia, 1.1%, 4.5%; Western Europe, 1.7%, 13.0%. The corresponding prevalence figures for children aged 6 to 7 years were reported as follows: global total, 1.8%, 10.2%; Asia-Pacific, 0.7%, 10.7%; Eastern Mediterranean, 3.8%, 12.4%; North America, 2.2%, 14.7%; Northern and Eastern Europe, 1.1%, 3.2%; Oceania, 3.2%, 26.8%; South-east Asia, 1.2%, 3.7%; Western Europe, 1.2%, 7.2%. (data source omitted in sample)
WORLDWIDE: If 10% of children and 5% of adults have asthma (figures that are conservative for western countries but may be overestimates in some developing countries), the global burden of asthma is on the order of 130 million people. (data source omitted in sample)
WORLDWIDE: In a 1993 Danish cross-sectional study of 851 unselected schoolchildren aged 6 to 17 years from a rural area the point prevalence of asthma diagnosed by a physician was 4%. In addition, at least 3.2% had symptoms of asthma indicating a point prevalence of 7.2%. Among the children in North Sweden (1994), most of them 14 years old, the point prevalence of asthma was 6.8%. A German study (1992) compared schoolchildren aged 9 to 11 years in Leipzig and Munich. In both towns, about 7% of the children had demonstrable asthma when examined in the hospital by use of lung function test and lung provocation test with cold air hyperventilation. The latest of this kind of study is from Finland (1996). In a study comprising 2011 children aged 7 to 12 years the point prevalence of asthma was estimated to be 4%. Studies that are solely questionnaire-based report the prevalence of asthma in schoolchildren in Great Britain to be 10.2% (1989) and 13.6% (1994), 19.5% (1987) in New Zealand, 17.7% (1988) and 21% (1991) in Australia. (data source omitted in sample)
INDIA: Epidemiological data on asthma from India in the past were rather limited. A good deal of information is now available, however, especially with reference to prevalence of asthma. Prevalence figures of 1.76% in 15,805 urban subjects of all ages at Patna and 1.8% among beneficiaries of the Central Health Scheme of Delhi were reported in the 1960s. Most subsequent studies have been conducted in the last decade. One of the important global efforts, the International Study of Asthma and Allergies in Childhood (ISAAC), included India as one of 56 countries under its ambit. The ISAAC study included children aged 13 to 14 years and 6 to 7 years from 14 centers from India. The methodology employed in the study consisted of a single page questionnaire meant for self-reporting of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema. The overall total Indian prevalence of "ever asthma" determined by written questionnaire was reported as 3.7% of 30,043 and 4.5% of 37,171 children in the 6- to 7-year and 13- to 14-year age groups, respectively. A very high prevalence of 14.4% and 12.4% was reported from one center (Kottayam, Kerala) in South India while all other centers reported prevalences between 1.3%-3.8% and 2.4%-6.5%, respectively, in the two age groups. A few other studies conducted independently among either school children or in the field have reported variable prevalences. The number of epidemiological studies in adults is even lower. Asthma prevalence in Mumbai was reported as 3.5% by physician diagnosis with the use of the European Community Respiratory Health Survey (ECRHS) methodology. The present authors used a validated Hindi adaptation of the International Union Against Tuberculosis and Lung Disease (IUATLD)-1984 questionnaire and rigid criteria for definition of asthma. They reported "true" prevalences, calculated with the help of an index derived from the sensitivity and specificity of the questionnaire, as 4% and 1.3% in men and women, respectively. The most authentic data on asthma prevalence in adults have now become available from the Indian Council of Medical Research (ICMR) study conducted simultaneously at four different centers in the country with the help of the above-mentioned questionnaire and methodology on 73,605 individuals aged 15 years or over. The overall presence of "ever asthma" was diagnosed in 2.4% of individuals while one or more respiratory symptoms were present in 4.3% to 10.5% of subjects. (data source omitted in sample)
U.S., EUROPE, ASIA-PACIFIC, AND JAPAN (SEVERITY DISTRIBUTION): The Asthma Insights and Reality surveys are the first large-scale surveys aimed at determining international variations in the severity, control, and management of asthma in children and adults. All surveys used the same standard protocol. The surveys were conducted in 29 countries in Western Europe, Central and Eastern Europe, Asia-Pacific, the United States, and Japan. Patients with current asthma were identified as those with asthma diagnosed by a physician and who were currently taking asthma medication or had asthma attacks and symptoms during the past year. All participants were interviewed after consenting to participate in the survey. The symptom questionnaire was based on the American Thoracic Society questionnaire. Severe persistent asthma was indicated by the presence of daytime symptoms more than 3 times a day or nighttime sleep disruption on at least most nights. Moderate persistent asthma was defined as daytime symptoms more than 2 times per day or nighttime sleep disruption at least twice a week. Mild persistent asthma was defined as daytime symptoms at least twice a week or nighttime sleep disruption at least twice per month. Intermittent asthma was defined as fewer symptoms than those for mild persistent asthma. A total of 10,939 asthmatic patients (3153 children and 7786 adults) participated in the 29 countries surveyed. There was a trend for Japanese and Asian-Pacific asthmatic patients to have less severe disease, whereas Central and Eastern Europeans reported more severe asthma symptoms. The distribution of asthma cases by symptom severity (severe, moderate, mild, and intermittent, respectively) in five regions was reported as follows: U.S., 19%, 22%, 16%, 43%; Western Europe, 18%, 19%, 19%, 44%; Asia-Pacific, 11%, 16%, 20%, 53%; Japan, 15%, 19%, 12%, 54%; Central and Eastern Europe, 32%, 27%, 19%, 22%. (data source omitted in sample)
AFRICA: Looking at about 120 papers from MEDLINE on asthma in Africa, the present authors found that asthma research is currently dominated by authors from South Africa, followed by authors from Nigeria, Tanzania, Ethiopia, Kenya, and The Gambia. Most are case studies, closely followed by cross-sectional studies, and then case-control studies. There have been very few cohort studies. Only a few studies use objective measures. Intercountry prevalence data are limited to the International Study of Asthma and Allergies in Childhood, in which seven African countries participated, including English-speaking regions (Ethiopia, 9.1%; Kenya, 15.8%; Nigeria, 13.0%; South Africa, 20.3%) and French-speaking regions (Algeria, 8.7%; Morocco, 10.4%; Tunisia, 11.9%). Symptom rates are lower than in industrialized countries, while only South Africa approaches rates found in the UK. The interpretation of these figures, however, is difficult; there might be an increase with gross domestic product and industrialization factors. Rural African regions always showed much lower asthma prevalence rates than urban areas. People living in rural grasslands rarely, if ever, suffer from allergic diseases and some do not even have a term to describe this condition. (data source omitted in sample)
LATIN AMERICA: Although asthma rates are low in many Latin American countries, rates in Brazil, Peru, and Costa Rica rival those found in developed nations with the highest prevalence, such as the UK, U.S., Australia, and New Zealand. Asthma prevalence among schoolchildren in Costa Rica is quite high: 26% of children have a doctor's diagnosis of asthma and 33% report having had wheezing in the last 12 months. The rates in Nicaragua are about half those in Costa Rica, with about 16% having a doctor's diagnosis of asthma and 15.5% reporting wheezing in the last 12 months. Why asthma prevalence rates differ so much is not known. (data source omitted in sample)
ASIA: The prevalence of asthma varies between 2% and 23% in Western countries, whereas in Southeast Asia the prevalence is between 1% and 13%. Evidence is also accumulating that the prevalence of asthma is increasing in both Western and Asian countries. The prevalence of asthma in Melbourne, Australia, increased from 19% in 1964 to 23% in 1990, whereas in Taiwan it increased from 1.3% in 1974 to 5.8% in 1991. A study was done to determine the prevalence of and factors associated with asthma in Chinese children aged 3 to 10 years living in Hong Kong in 1989. The study group involved 535 subjects, among whom the prevalence of asthma was 6% and the prevalence of eczema 6.8%. Asthma was reported in 15% of children with IgE levels greater than 100 IU/mL. The prevalence value obtained in the present study was similar to that of 6.7% in another Hong Kong study conducted in 1989 and lower than that study's 9% prevalence for wheezing. Prevalence of asthma in other countries in the region is as follows: (1) Japan, 11%; (2) Malaysia, 13.8%; (3) Singapore, 4.8%; (4) Taiwan, 5.8%. (data source omitted in sample)
CANADA: The percentage of the Canadian population aged 12 and over who reported that they had been diagnosed by a health professional as having asthma (males versus females) was reported as follows: 1994-1995, 6.5% (6.2% vs 6.7%); 1996-1997, 7.2% (6.0% vs 8.4%); 1998-1999, 8.1% (7.2% vs 8.9%); 2000- 2001, 8.4% (6.9% vs 9.9%). The percentage of a given age group who reported that they had been diagnosed by a health professional as having asthma in 1994-1995 and 2000-2001, respectively, was reported as follows (percentages for males versus females in parentheses; figures marked "E" should be used with caution). 12 to 14 years: 12.4% (13.3%E vs 11.3%E); 12.7% (13.2% vs 12.1%). 15 to 19 years: 11.9% (10.7% vs 13.3%); 12.6% (11.9% vs 13.3%). 20 to 24 years: 8.3% (7.7%E vs 8.9%); 10.9% (8.3% vs 13.7%). 25 to 34 years: 6.9% (6.8% vs 6.9%); 9.0% (7.0% vs 11.0%). 35 to 44 years: 4.7% (3.9% vs 5.5%); 7.3% (5.8% vs 8.8%). 45 to 54 years: 4.7% (4.3%E vs 5.1%); 6.9% (4.7% vs 9.0%). 55 to 64 years: 4.9% (4.3%E vs 5.5%); 6.9% (4.9% vs 8.9%). 65 to 74 years: 4.9% (5.5%E vs 4.5%E); 7.1% (6.3% vs 7.9%). 75 years and older: 4.5%E (4.5%E vs 4.5%E); 7.3% (7.9% vs 6.9%). (data source omitted in sample)
GERMANY: Generally, the prevalence of atopic diseases is higher in industrial countries than in Eastern European and developing countries. So far, studies on prevalence and incidence have mainly covered school children, and studies in adults are still rare. The aim of the present study was to estimate the lifetime prevalence of atopic dermatitis, asthma, and hay fever in an elderly population aged 50 to 74 years, and to investigate the relationship between atopic diseases and sociodemographic factors in adults. The ESTHER study is a prospective cohort study on new approaches to the prevention and early detection of chronic diseases among older adults. The study recruited 9961 subjects who had a general health check by a general practitioner between June 2000 and December 2002, were between ages 50 and 74 years, speak German, and reside in Saarland, Germany. This analysis is based on information obtained from the patients' questionnaire. Prevalence rates and odds ratios (respectively) for self-reported asthma were reported as follows. Gender: female, 5.4%, 1.0; male, 5.7%, 1.1. Age (years): 50 to 59, 5.6%, 1.0; 60 to 69, 5.5%, 1.0; 70 to 74, 5.3%, 1.0. Duration of school education: 9 years or fewer, 5.3%, 1.0; 10 to 11 years, 6.7%, 1.3; more than 11 years, 6.0%, 1.3. Size of place of residence before age 18 years: village, 5.4%, 1.0; small town, 6.1%, 1.1; large city, 5.4%, 1.0. The age-specific lifetime prevalence of asthma was reported as follows for females versus males: 50 to 55 years, 6.5% vs 4.9%; 55 to 60 years, 5.9% vs 4.9%; 60 to 65 years, 5.0% vs 4.8%; 65 to 70 years, 5.1% vs 7.7%; 70 to 75 years, 4.6% vs 6.1%. (data source omitted in sample)
GERMANY: The aim of this study was to investigate the prevalence of asthma and to provide an estimate of the cost burden in Germany. Since there is no national registry, this study estimates the direct and indirect medical costs and prevalence of asthma in Germany by analyzing medical claims data, augmented by data from the Federal Office of Statistics (Statistisches Bundesamt) and the Association of German Pension Funds. Categories of expenditure for direct costs were inpatient care (hospital costs), outpatient care and inpatient rehabilitation. In the hospital sector, patients with asthma as a leading or primary discharge diagnoses were identified using ICD-9 Code 493. Categories for the estimation of indirect costs considered were sick benefit, early retirement, and premature death. The tracer procedure used shows a total prevalence of asthma of 6.34%. The highest peak of the curve lies in infancy and early childhood, with 25% for males and about 17% for females. After the age of 4 years a steady decline in prevalence can be seen. Males have a higher prevalence in childhood and later in life from age 68 years onward. Females have a higher prevalence than males from ages of about 17 to 62 years. For both sexes prevalence rates at ages 16 to 62 years are 3% to 7%. From age 62 years onward a rise in prevalence in both sexes can be observed, with the male prevalence exceeding female prevalence. Overall prevalence in children and young adults (ages 0 to 19 years) is 11.8% for males and 9.2% for females. (data
source omitted in sample)
GERMANY: The authors examined the relationship between asthma and current (occurring in the past four weeks) and lifetime mental disorders. The sample of this core survey was drawn from the population registries of subjects aged 18 to 79 years living in Germany in 1997. It represents a stratified random sample from 113 communities throughout Germany with 130 sampling units. The prevalence of asthma was 2.7% (current) and 5.74% (lifetime), which is consistent with prevalence estimates from other western countries. (data source omitted in sample)
ITALY (PEDIATRIC POPULATION): The Italian Studies of Respiratory Diseases in Childhood and the Environment project, part of the worldwide International Study of Asthma and Allergies in Childhood, was designed specifically to evaluate changes over time in the prevalence of wheezing, allergic rhinoconjunctivitis, and atopic eczema symptoms among 6- to 7-year-old and 13- to 14-year-old youths in Italy during the period of 1994 to 2002. The surveys were performed in areas of northern and central Italy, including metropolitan areas (cities with more than 500,000 inhabitants). Each area was required to sample at least 1000 subjects for each age group. 16,115 and 11,287 children completed questionnaires in phases I and II, respectively, and 19,723 and 10,267 adolescents returned completed questionnaires in phases I and II. For children and adolescents, respectively, the prevalence rate in 1994-1995 versus the rate in 2002 of selected respiratory and allergic symptoms was reported as follows: asthma (lifetime), 9.1% vs 9.5%, 9.1% vs 10.4%; severe asthma (past 12 months), 1.6% vs 1.6%, 2.1% vs 2.3%. (data source omitted in sample)
ITALY: According to Italy's ISTAT (Instituto Nazionale di Statistica), the 1999-2000 rate (per hundred) of people reporting asthma was 3.1 (males, 3.1; females, 3.1). (data source omitted in sample)
ITALY: The present study evaluated, using a repeated survey approach, whether any significant variation in the prevalence of asthma, asthma-like symptoms, and allergic rhinitis had occurred in the adult population of northern Italy during the 1990s. The survey was performed in 3 centers of northern Italy, Turin, Pavia, and Verona, located in the plain of the Po River and characterized by a temperate climate. The adjusted prevalence of respiratory symptoms and antiasthmatic treatment in 1991 to 1993 versus 1998 to 2000, respectively, in the 3 Italian centers was reported as follows: asthma attacks, 3.6% vs 3.2%; wheezing, 9.8% vs 9.6%; wheeze with breathlessness, 2.8% vs 2.1%; wheezing without a cold, 6.7% vs 6.5%; chest tightness, 7.9% vs 6.5%; shortness of breath, 7.0% vs 5.2%. No significant change was observed in the adjusted prevalence of asthma attacks, which declined slightly from 3.6% in 1991 to 1993 to 3.2% in 1998 to 2000. The prevalence of asthma attacks, while decreasing in people older than 26 years from 3.8% to 3.2%, increased slightly from 3.6% to 4.3% in people aged 20 to 26 years. The prevalence of asthma attacks and asthma-like symptoms was usually higher in urban than in suburban areas; the difference was significant for asthma attacks. Overall, the percentage of people who self-reported to be under antiasthmatic treatment increased slightly from 1.9% to 2.5%, although not significantly. This increase was observed in suburban areas (from 0.7% to 2.9%) but not in urban areas (from 2.3% to 2.5%), as denoted by the significant interaction between site of residence and time of survey. The increase in treatment was substantial in people aged 20 to 26 years (from 2.0% to 3.8%) and only moderate in older age classes (from 2.0% to 2.4%), but this difference in temporal trend was not significant. The proportion of people free from asthma attacks increased among subjects currently taking medicines for asthma in all centers from 21.8% in 1991-1993, to 31.8% in 1998-2000. (data source omitted in sample)
INDIA: There is very limited data on asthma epidemiology from the developing world, including India. The overall burden of asthma in India is estimated at more than 15 million patients. However, India is a vast country with immense geographical, economical, racial, religious, and socio-political diversity. There are obvious differences in prevalence of disease and approach to management of health problems. The authors have adapted a questionnaire to assist in field diagnosis of asthma for epidemiological purposes and have estimated prevalence of disease in the local population, both in children and adults. Prevalence of asthma in adults age 15 and older was studied in different parts of the country with a multicentric design using uniform methodology. The questionnaire envisaged for use in this study had two components. The first part was aimed at collecting information on respiratory symptoms and establishing a diagnosis of asthma based on this data. The second component was aimed at collecting information on possible demographic and environmental exposure factors influencing the prevalence of asthma. Data from a total of 73,605 respondents were included in the final analysis. There were 37,682 (52%) men and 35,923 (48%) women. While about half of the subjects were aged between 15 and 34 years, about 10% of individuals were aged 65 years or more at each center. As per the definition used in the survey, asthma was present in 2.28%, 1.69%, 2.05%, and 3.47% of respondents, respectively, at Chandigarh, Delhi, Kanpur, and Bangalore, with an overall prevalence of 2.38% (men, 2.21%; women, 2.56%). Overall prevalence was reported as 2.55% in urban areas (men, 2.29%; women, 2.81%) and 2.18% in rural areas (men, 2.12%; women, 2.24%). Prevalence was relatively higher among female respondents of urban areas at Delhi, Chandigarh, and Bangalore. (DISCUSSION) There is very limited information on prevalence of asthma among adults in India. Nevertheless, the present estimates are close to the figure of 2.78% reported three decades ago in a middle-aged urban population. These results are also similar to the asthma prevalence (3.5%) reported in Mumbai more recently using a "clinician diagnosis" based on the European Community Respiratory Health Survey protocol. As stressed earlier, the largest obstacle in comparing prevalence estimates across two or more fields studies relates to methodological differences in study design, disease definition, and data analysis. Another important finding from the data is that the study population at Bangalore had a higher prevalence of asthma as compared to the other three north Indian cities, even after adjustment of other risk factors associated with asthma. While this data is insufficient to draw any definite conclusions regarding north-south differences in asthma prevalence in India, it certainly opens new areas for looking into ethnic variations in disease prevalence, severity, and morbidity in this country with such great heterogeneity. (data source omitted in sample)
KOREA: Recently, several large-scale studies of different populations in Korea have reported asthma prevalence ranging from 2% to 13%. These differences are probably ascribable to different case definitions, methodologies, and a tendency to survey children rather than adults due to the relative ease of implementing studies in a school environment. According to the latest summary issued by the global burden of asthma by the Global Initiative for Asthma (GINA) program, the prevalence of clinical asthma in Korea is estimated to be 3.9%. The prevalence of asthma tended to be higher in children than in adults and was found to depend significantly on their place of residence, for example, it was found to be higher in Seoul than in provincial cities. According to 1998 data, childhood asthma was less prevalent in Korea than in other developed countries. However, among the elderly (aged 65 years or older), its prevalence was found to be high at 12.7% in 2001, which is about 3 times higher than among English or U.S. elderly. Although estimates of asthma prevalence in older age groups differ greatly between countries because of overlapping diagnoses and poor patient perception of symptoms, this rate is unexpectedly high. In the elderly, asthma is an important problem because it is usually underdiagnosed and hence inadequately treated. Interestingly, Korean adults and children appear to have a later average age of asthma onset than other Asian populations. This is likely to be due to the underdiagnosis of early stage asthma by general physicians. Some investigators have reported that an underdiagnosis rate by general physicians was 21%. Another contributing factor may be that a high proportion of Korean people, at least initially, turn to traditional medicine for medical help, which delays the diagnosis until they are referred to hospitals or emergency department with severe symptoms. Finally, racial differences may be a consideration. (data source
omitted in sample)
THAILAND: The authors conducted a nationwide survey of respiratory health in the adult population of Thailand to determine the prevalence of asthma as well as bronchial hyperresponsiveness (BHR). The target population was the adult population in Thailand aged 20 to 44 years. The authors used established networks of local health officers and health volunteers in each district to recruit the selected subjects for the survey. Each subject underwent a questionnaire interview, spirometry and methacholine challenge testing. Spirometry and bronchoprovocation were performed on 3245 subjects and 3141 subjects, respectively. The prevalence of current diagnosed asthma was 2.15% (74 of 3443 subjects). The prevalence of definite asthma was 2.91% (92 of 3163 subjects). The prevalence of BHR defined as a positive bronchoprovocation result was 3.31% (104 of 3141 subjects). The prevalence of BHR defined as a positive bronchoprovocation result plus a positive reversibility result was 3.98% (126 of 3163 subjects). The present nationwide cross-sectional survey revealed the prevalence of current diagnosed asthma in 2.15%, definite asthma in 2.91%, and BHR in 3.31% to 3.98% of the adult Thai population. Compared to western countries and Australia/New Zealand, the prevalence of asthma in Thailand is much lower. (data source omitted in sample)
SINGAPORE (WITH BRITAIN): The International Study of Asthma and Allergies in Children (ISAAC) was formed in 1992. In phase 1 of this ISAAC study, standardized written and video questionnaires were developed. The authors have analyzed the results of the ISAAC phase 1 written questionnaire survey of schoolchildren in Singapore. The population consists of Chinese (75%), Malays (15%), and Indians (10%), so racial differences in the prevalence and severity of asthma, rhinitis, and eczema were evaluated. The questionnaire concentrated on past and current wheezing episodes, wheezing frequency, sleep disturbance and speech limitation during attacks, exercise induced wheezing, persistent cough unrelated to respiratory infections, and a doctor's diagnosis of asthma. The authors studied two age groups of schoolchildren (6 to 7 years and 12 to 15 years). 30 schools from all parts of Singapore were randomly selected, of which 21 consented to participate. The self-reported prevalence of doctor-diagnosed asthma was reported as follows: overall, 20.0%; ages 6 to 7 years, 18.5%; ages 12 to 15 years, 20.7%; males, 22.1%; females, 17.5%; Chinese, 19.9%; Malay, 21.3%; Indian, 17.2%. The prevalence of diagnosed asthma was higher in this population (20.0%) than in a British study (13.1%). Thus the local prevalence figures probably lie somewhere between those of the West and developing countries. The reported cumulative and current prevalence of wheezing in southern China are reported to be as low as 1.9% and 1.1%. Singaporean Chinese are of southern Chinese descent, suggesting that geographical differences in wheezing and asthma prevalence may be influenced more by environment than genetics. (data source omitted in sample)
SINGAPORE: This study was undertaken to examine differences in the prevalence of adult asthma among the three major ethnic populations of Singapore. Over 85% of households (those within the low to middle income brackets in Singapore) live in modern, low cost, high rise flats in public housing estates. A stratified two-stage cluster disproportionate random sample of adults aged between 20 and 74 years was selected. Of 3940 eligible persons between 20 and 74 years, 2868 persons (72.8%) were interviewed. Asthma was defined in a number of ways in the survey: (a) episodic wheeze; (b) episodic wheeze and "attacks" of shortness of breath; (c) nocturnal "attacks" of wheeze or shortness of breath; (d) any of the above symptoms with a physician diagnosis of asthma ("physician diagnosed asthma") in the absence of known cardiac disease. The cumulative sex- and age-standardized prevalence rates of physician-diagnosed asthma by ethnic group were reported as follows: Chinese, 3.6%; Malay, 6.0%; Indian, 6.6%. Higher rates of asthma were observed among Malays and Indians than Chinese in Singapore. This was not explainable by differences in socioeconomic status or atopy. (data source omitted in sample)
JAPAN (PEDIATRIC POPULATION): A large-scale survey was conducted to assess contributing factors in atopic disorders in addition to the prevalence of asthma and atopic dermatitis (AD) in children aged four years and under. 24,631 children aged four and under in 70 towns in Gunma Prefecture, Japan, were surveyed. Members of prefectural health centers distributed the self-administered questionnaire with the support of public health nurses in each local government area. The response rate was 70.7%. The change in the prevalence of asthma by increasing age was reported as follows for boys versus girls: age 0, 0.6% vs 0.4%; age 1, 2.1% vs 1.2%; age 2, 2.8% vs 1.7%; age 3, 6.0% vs 2.5%; total, 2.6% vs 1.3%. Prevalence of asthma increased linearly and significantly with the increasing age of the patient. The prevalence of asthma in the cities was 2.9% among boys and 1.2% among girls. The prevalence in towns or villages was 2.3% among boys and 1.4% among girls. (data
source omitted in sample)
JAPAN: Around 50 years ago, asthmatic patients accounted for approximately 1% of the population in Japan; this has now risen to more than 3% in adults and 3% to 5% in school children. A prevalence study of allergic diseases was undertaken in several health centers and schools, involving 8288 school children and 10,937 adults. This study showed the prevalence of asthma to be 6.4% in children and 3.0% in adults. Another study on 1054 Japanese school children showed a prevalence of asthma of 5.9%. (data source omitted in sample)
HONG KONG: Subjects were recruited as part of a population survey of the social and health profile of elderly Chinese aged 70 years and over. In Hong Kong, the prevalence of asthma was reported as follows in men vs women: 70 to 79 years, 6.0% vs 4.2%; 80 years or older, 6.2% vs 4.4%; overall, 6.1% vs 4.3%. (data source omitted in sample)
UNITED KINGDOM: The aim of this paper is to provide a succinct update of trends in available national-level data on asthma in the UK over the past 50 years (1955 to 2004). Data were derived from a variety of sources chosen for the reliability of their estimates over time. They comprised routine prescribing, admissions and mortality data, large-scale general practitioner databases, national survey series, and local ad hoc surveys of asthma diagnosis and symptoms. The sources of data described in this review do not provide a complete picture of trends in morbidity and use of health services for asthma. In particular, there aren't adequate data on morbidity in adults, nor are there data on the use of emergency or outpatient departments. Nevertheless, a number of conclusions may be drawn. Trends in the prevalence of childhood asthma generally indicate an increase in asthma symptoms of all grades of severity from the 1960s, when the earliest surveys were done. There is some evidence that trends flattened or even began to fall in the late 1990s and early 2000s. Evidence for adults is sparse and conflicting, but national surveys suggest that little change has occurred in recent years. There has been an upward trend in a lifetime diagnosis of asthma and in the proportion of currently wheezing children diagnosed as having asthma. Hospital admissions increased until the late 1980s and have been declining since. The rise and fall in hospital admissions was highest in younger age groups but affected all age groups around the same period, indicating that any important cohort effect was unlikely. The incidence of asthma episodes presenting to general practitioners rose in all ages to a plateau in the mid-1990s and has declined since. The prevalence of treated asthma in general practice rose and then flattened out during the 1990s, while at the same time incident asthma in general practice remained steady. (DISCUSSION) The subsequent decline in the incidence of severe asthma indicated by trends in both hospital and general practitioner data, during a time when the prevalence of treated asthma in general practice has remained fairly stable, is consistent with the greater penetration and effective use of inhaled corticosteroids. The recent fall in prevalence of moderate to severe asthma in 13- to 14-year-old children is also consistent with this, although it would not explain the concomitant fall in mild symptoms. (data source omitted in
sample)
ENGLAND: The 2001 Health Survey for England was designed to provide a representative sample of the population of all ages living in private households in England. Interviews were obtained with 15,647 adults (aged 16 and over) and 3993 children (aged under 16) resident in 9373 households. Interviews were carried out in 74% of the eligible households and the estimated response rate was 67%. The present report deals only with adults aged 16 and over. Overall, 35% of men and 32% of women had a history of wheezing. The prevalence of wheezing over the last 12 months was 21% for men and 20% for women. Wheezing symptoms were more common among older age groups for men but no consistent age pattern was evident among women. The prevalence of doctor-diagnosed asthma was estimated as follows in men versus women: ages 16 to 24 years, 23% vs 25%; ages 25 to 34 years, 15% vs 20%; ages 35 to 44 years, 12% vs 16%; ages 45 to 54 years, 10% vs 13%; ages 55 to 64 years, 14% vs 14%; ages 65 to 74 years, 10% vs 13%; ages 75 and older, 9% vs 12%. The lifetime prevalence of doctor-diagnosed asthma was 13% among men and 16% among women. Asthma diagnosis was higher for women across all age groups and decreased with age for both genders. About 1% of men and women reported that asthma had been diagnosed in the last 12 months. The prevalence of doctor-diagnosed asthma was higher in 2001 than 1995-1996, for both men and women. Increases for men were from 11% to 13%, and for women from 12% to 16%. The differences were systematic and consistent across age groups. Increases in the prevalence of doctor-diagnosed asthma were particularly pronounced among men aged 16 to 24 and women aged 16 to 34. Among men, differences were statistically significant for the age groups 16 to 24 years, 25 to 34 years, 45 to 54 years, and 55 to 64 years. Among women, differences were statistically significant for the age groups 16 to 24 years, 25 to 34 years, 35 to 44 years, 55 to 64 years, and 75 years and older. (data source omitted in sample)
UNITED KINGDOM: The authors conducted a survey over a representative cross-section of the UK population which looked at the prevalence of the main types of allergic disease. The survey was based on a representative sample of 2000 adults (male and female) aged 16 years or more. The current estimate of the prevalence of asthma for the general UK population is about 6%. Surveys focus on particular groups, e.g., studies of children report the prevalence of asthma to be higher (13.1% and 21%) compared with upper estimates for adults (8.4% and 12%). The estimate from the current survey (12%) is higher than clinical estimates, however, if an average is taken over all the recent studies performed in the UK; ignoring the demographic nature of the sample, a figure of about 11.6% is obtained. This is consistent with the results reported here. Recent estimates for asthma prevalence in other regions and demographic samples range from 2.5% to 18% of the measured population, indicating a variation in the scale of the problem worldwide. (data
source omitted in sample)
UNITED KINGDOM: A 1995 UK study reported variations in the prevalence of asthma in children in England, Wales and Scotland. Pupils of 93 large mixed secondary schools (ages 12 to 14 years) self-completed 27,507 questionnaires (85.9% response rate). The prevalence of selected clinical variables was reported as follows: asthma symptoms, 33.3% (for wheezing in the past twelve months); ever having had a diagnosis of asthma, 20.9%; current use of an inhaler, 15.8%. In the 1991 ISAAC pilot study in children aged 13 to 14 in west Sussex, the prevalence of wheezing in the previous twelve months was 29%. (data source omitted in sample)
SPAIN: This study forms part of the European Community Respiratory Health survey (ECRHS). From March 1992 to April 1993, subjects were invited to attend a center in each of five cities in Spain. Overall, 2646 individuals responded to the ECRHS respiratory questionnaire and 1797 individuals completed a bronchial responsiveness challenge. For individuals aged 15 years or under, the prevalence is shown for current asthma versus past asthma, as follows: Female sex (1.3% vs 3.0%), parental asthma (6.9% vs 4.7%), indoor atopy (4.2% vs 7.1%), outdoor atopy (2.4% vs 4.0%), both indoor and outdoor atopy (9.3% vs 16.4%), having 1-2 older siblings (2.2% vs 1.3%), having 0 older siblings (1.9% vs 1.8%), lower respiratory infection (LRI) before the age of 5 years (11.1% vs 25.5%), exposure to any animal (1.9% vs 3.5%). For individuals aged older than 15 years the prevalence is shown for current asthma versus past asthma, as follows: Female sex (5.1% vs 3.2%), parental asthma (6.4% vs 7.4%), indoor atopy (4.9% vs 3.7%), outdoor atopy (8.3% vs 6.2%), both indoor and outdoor atopy (17.2% vs 4.3%), having 1-2 older siblings (1.5% vs 1.1%), having 0 older siblings (1.8% vs 1.0%), LRI before the age of 5 years (6.2% vs 0.9%), exposure to any animal (3.2% vs 2.6%). (data source omitted in sample)
SWITZERLAND: Precise epidemiologic data for the prevalence of childhood asthma were lacking for Switzerland until, in 1990, a stratified cluster sampling of school children was performed. In children age 7, 12, and 15 years in Switzerland the prevalence of any asthma symptom during the previous 12 months was 17.5%, while only 4.8% of the children reported the diagnostic label "asthma." The 12-month prevalence of chronic night cough was 12% (comparable to other European data). Wheeze (5.9%) was reported less often in Switzerland than in England. (data
source omitted in sample)
FINLAND: A prospective cohort study from Finland examined the prevalence of asthma in the Finnish Twin Cohort. The age-standardized prevalence of asthma in 1975 was 2.0% among men and 2.2% among women, and there were no significant differences between singletons and twins. The 1981 rates were quite similar (2.1% and 2.3% for men and women). In 1990, there was some increase for both sexes, with rates of 2.9% for men and 3.5% for women. (data source omitted
in sample)
FINLAND: There are few extensive epidemiological population studies on the incidence and prevalence of asthma in Finland. About 150,000 Finns, or 3% of the population, have been diagnosed as asthmatics. A similar percentage of the population is on drug therapy or receives social security because of asthma. Depending on the methodology, study material and definition of asthma, the prevalence rate may be up to 5% or 250,000 individuals. The age distribution of the asthmatic population is as follows: below 15 years of age, 12%; ages 15-44, 29%; ages 45-64, 32%; over 65 years of age, 27%. (data source omitted in sample)
ISRAEL: One survey determined the point prevalence of asthma among 17-year-old Israeli males to be 5.0%, with a cumulative prevalence of 7.9%. When the survey was repeated 4 years later, the percentages for these variables were 5.9% and 9.6%, respectively. (data source omitted in sample)
EGYPT: The aims of this study are to determine the prevalence of asthma and allergic rhinoconjunctivitis in schoolchildren in Cairo, Egypt and to investigate the role of socioeconomic status on prevalence of asthma and allergic rhinoconjunctivitis. The study population was taken from among 11- to 15-year-old children in the first and second years of preparatory secondary school in the El Nozha area of Cairo. These schools comprise state schools, experimental language schools and private schools. Experimental language schools are fee-paying government schools and are classified with private schools in the analysis. An adapted version of the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to measure symptom prevalence. The independent variable was the school type. Questionnaire delivery was controlled. Use of the ISAAC video was not within the resources available. A total of 3,002 children aged 11 to 15 years were eligible to receive a questionnaire. From these, 2645 (88.1%) completed questionnaires were received. Overall, the prevalences of wheeze ever, wheeze during the last year, and physician-diagnosed asthma were 26.5% (697 out of 2631), 14.7% (379 out of 2570), and 9.4% (246 out of 2609), respectively. Children from state schools had a higher prevalence of severe asthma symptoms than those in fee-paying schools (13.1% versus 4.9%). The proportion of individuals with severe asthma symptoms but without a diagnosis of asthma is higher in state schools than in fee-paying schools (63.3% of those with severe symptoms versus 29.6%). Severity is also higher in children whose parents have not had university-level education. Among 11- to 15-year-old schoolchildren in Cairo, the overall prevalence of wheezing in the last year was 14.7% and of physician-diagnosed asthma was 9.4%. This study clearly shows that allergic rhinoconjunctivitis and asthma symptoms are much more prevalent among those from poorer backgrounds. Children attending state schools also showed a higher prevalence of severe asthma symptoms but were much less likely to have a physician diagnosis of asthma, which points to discrepancies in access to healthcare. Asthma is relatively common, and probably underdiagnosed and undertreated, particularly among children from less wealthy families in Cairo. (data source omitted in sample)
|