Skip Navigation Links
ICD Code: 493. Asthma



ICD Code: 493. Article Review
Title: Larsson L; "Incidence of Asthma in Swedish Teenagers: Relation to Sex and Smoking Habits." Thorax; V.50; 1995; p260
      STUDY DESIGN: A questionnaire was sent in 1990 to all 3627 individuals born in 1974 living in the county of Jamtland and Gastrikland, the southern part of the county of Gavleborg in central Sweden. Individuals reporting airway disease or obstructive symptoms were investigated with a further interview and lung function tests. The cross-sectional questionnaire study was repeated in 1993. The incidence of asthma was calculated in the 2308 individuals who answered the questionnaire in both surveys and who were found not to have asthma in 1990.
      INCIDENCE (SWEDEN): The yearly incidence of symptoms was 2.7% for shortness of breath and 1.7% for frequent wheezing. The yearly incidence of asthma, calculated as the proportion of the population reporting that they had asthma or physician diagnosed asthma, was 1.2% and 1.1%. The use of a combination of diagnosed disease and current use of asthma medication gave an incidence of 0.8%. The corresponding figure for attacks of shortness of breath and current use of asthma medication was 1.2%. The combination of frequent wheezing and attacks of shortness of breath resulted in the highest incidence (1.3%), while frequent wheezing and current drug use resulted in the lowest incidence (0.8%). In all definitions the incidence was significantly higher in female than in male subjects.
      SEX DIFFERENCES: The results of this study suggest that the incidence of asthma in late adolescence is about 1%, and that there is a sex difference with a higher incidence in female subjects. The reason for the increased incidence of asthma in women is unknown. The incidence is not affected by the age at onset of menarche or puberty, indicating that hormonal factors are not the principal explanation. The relation between the incidence of asthma and atopic disease does not differ between the sexes and does not explain the observed differences in incidence.
      DISCUSSION: The criteria used to define asthma have a considerable impact on the results. The definitions including self-reported disease all had a high specificity, while the sensitivity was lower when validated against asthma associated symptoms and signs of bronchial lability. The figures based on self-reported disease reported here are therefore probably minimal values for the incidence of asthma.

Search Criteria: Text - Thorax; V.50; 1995; p260