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ICD Code: 493. Asthma



ICD Code: 493. Article Review
Title: Ownby DR et al; "Incidence and Prevalence of Physician-Diagnosed Asthma in a Suburban Population of Young Adults." Annals of Allergy, Asthma, and Immunology; V.77; 10/96; p304
      INCIDENCE (U.S.): Four published studies of asthma have provided incidence estimates for adults living in the U.S. Three were community surveys in Michigan, Arizona, and Minnesota, while the fourth study is an estimate from the National Health and Nutrition Survey I and Follow-Up Survey. The yearly incidence of asthma in adults ranged from 1.4 to 3.5 per 1000 individuals. The study from Rochester, Minnesota, is unique because the investigators were able to study the incidence of asthma over a 20-year period (1964 to 1983) for various age groups. The Rochester investigators concluded that the incidence of asthma had increased in children and adolescents, but not in adults during the 20 years studied.
      STUDY DESIGN: This study determined the incidence and prevalence of asthma in a population of young adults living in suburban Detroit. All pregnant women insured by Health Alliance Plan health maintenance organization and residing in an area of suburban Detroit, defined by contiguous zip codes, were eligible for recruitment during pregnancy if they were 18 years of age or older and due to deliver between April 15, 1987 and August 31, 1989. Women meeting eligibility criteria were invited to participate by study nurses during prenatal visits, usually during the third trimester. Infants enrolled in the study were followed at a minimum of yearly intervals. The homes of all participating infants, who were still living in the Detroit metropolitan area, were visited by a study nurse within 1 month of the child's fourth birthday. The question concerning asthma on both the predelivery and 4-year questionnaires was, "Has a doctor ever said that you (or your spouse) have or have had asthma?" To verify the occurrence of a new physician diagnosis of asthma during the 4-year interval, all respondents who provided a different answer were contacted and the differences were reconfirmed. Only those individuals who were identified by themselves or their spouses as having a new diagnosis of asthma in the four years were counted as incident cases.
      RESULTS: 841 infants were enrolled in the study representing 80% of those eligible, and 777 of the mothers described themselves as white. The parents were relatively young and well educated: mean ages were 28.7 and 30.9 years for mothers and fathers, respectively; 30.7% and 43.5% of mothers and fathers, respectively, had graduated from college. Cigarette smoking was relatively uncommon.
      INCIDENCE: Based on the new asthma diagnoses, the average annual incidence of asthma was 5.2 per 1000 in women and 1.5 per 1000 in men, a gender difference which was of borderline significance. The relative risk of asthma for women compared with men was 3.43. The incidence of asthma was higher in parents less than 30 years of age at entry into the study compared with those 30 years or older, 5.3 versus 1.5 per 1000.
      DISCUSSION: The 3.4 per 1000 per year overall incidence of asthma, with a higher risk in women and in those more than 30 years old, found in this young adult population is similar to incidence estimates reported in other U.S. populations of similar age over the past 20 years. A significant limitation of this study and of many previous epidemiologic studies of asthma is the reliance on self-reports of a physician diagnosis. This study, like some others, included limited numbers of nonwhite individuals. Unless a study includes sufficient numbers of each racial group, it is impossible to compare the incidence of asthma between racial groups after controlling for the effects of socioeconomic status.

Search Criteria: Text - Annals of Allergy, Asthma, and Immunology; V.77; 10/96; p304