GENES FOR ASTHMA - AN ANALYSIS OF THE EUROPEAN-COMMUNITY RESPIRATORY HEALTH SURVEY

Besides environmental triggers, a family history of asthma is a strong risk factor for the development of asthma in offspring. The pooled da ta from 13,963 interviews of randomly selected, 20 to 48 yr-old partic ipants from the 30 centers of the European Community Respiratory Healt h Survey (ECRHS) were analyzed with conventional logistic regression a nd a Class A regressive model adapted for the segregation of various t ransmission modes in families. The asthma prevalence in the interviewe d index generation was 6.9% (95% confidence interval [CI]: 6.5 to 7.3) , and in the parent generation was 6.1% (5.8 to 6.4). As with asthma p revalence, the risk of a subject having asthma if a parent had asthma also had a large geographic variation across the survey centers. The m ean risk if a father had asthma was 2.9 (2.4 to 3.5), and if the mothe r had asthma was 3.2 (2.6 to 3.9). The risk increased to 7.0 (3.9 to 1 2.7) if both parents were affected. For developing extrinsic asthma, e xtrinsic asthma in any parent was a greater risk factor (4.9 [3.9 to 6 .0]) than intrinsic asthma of the parent (1.5 [0.8 to 2.6]), and the r isk for women was slightly higher than that for men (4.3 [3.3 to 5.5] versus 3.6 [2.6 to 5.0]). Applying different segregation models, only a model for a two-allele gene with a codominant inheritance could not be rejected, assuming a major gene with a population frequency of 24.2 %. Further results make a multilocus/threshold model likely. In conclu sion, a history of asthma in parents is a strong risk factor for asthm a in the offspring. Under the assumptions of the applied segregation a nalysis, at least one major gene exists which could be a gene involved also in allergy. However, asthma is not fully described by a single-g ene model. The risk for asthma varies within the European countries, a nd should be seen in the context of a complex genetic and environmenta l pathophysiology.