Familial risk of asthma among adolescents and their relatives in Taiwan

Although family studies have established that asthma has a hereditary, basi s, little evidence has been presented about the family, risk of simple asth ma (AS or nonatopic asthma) and asthma with other atopic diseases (A WAD or atopic asthma) after adjusting for potential risk factors. In this study, data were collected on demographic variables and a wide range of known risk factors for asthma. Study, participants it-ere asthmatic adolescents and c ontrols, and their relatives. The role of a familial history, of asthma and atopic diseases in predicting asthma risk among asthmatic adolescents and their relatives was evaluated in a population-based family study, conducted in southern Taiwan. Asthma risk factor data were collected through telepho ne interviews with students' parents for 207 asthmatic adolescents 11-16 ye ars of age, their 1600 relatives, and 207 nonasthmatic adolescents in the c ontrol group and their 1638 relatives. The results show (after adjusting po tential confounders) that a family history, of asthma is highly, associated with asthma in adolescents. Having two or more family members with asthma was associated with a 3.4-fold (95% confidence interval [CI] = 1.0-12.0) in creased risk of asthma among adolescents. Logistic regression was used to a ssess the effects of having an asthmatic relative and the effect of atopic diseases among relatives of cases. Having a family history, of asthma and o ther atopic conditions, such as rhinitis and atopic dermatitis (adjusted od ds ratio [AOR] = 3.64, 95% CI = 2.29-5.74 and AOR = 1.94, 95% CI = 1.53-2.4 6, respectively), was found to be a significant predictor of asthma in chil dren. Along with a history, of allergic rhinitis or atopic dermatitis, fami lial risks of asthma occurring in adolescents with and without other atopic diseases will be analyzed separately,. A critical finding was the signific ant difference in a risk of asthma and atopic diseases among the relatives of asthma cases with atopic diseases and controls. However, for relatives o f asthma cases without atopic diseases compared to control probands, AORs w ere highly, significant for family, history of asthma, but not for the fami ly, history, of atopic diseases. These findings suggest that both forms of asthma may, be hereditary, but there are differences in their modes of inhe ritance. Atopic status itself did not predispose a child to AS. A concomita nt inheritance of a predisposition to asthma and atopic condition for AWAD cases nus suggested.