Family patterns of asthma, atopy and airway hyperresponsiveness: an epidemiological study

Background The patterns of inheritance of asthma have largely been explored using data of symptom history collected by questionnaires which are subjec t to bias and which may therefore distort the measured relationship. Objective The purpose of this study was to examine family patterns of aller gic disease using objective measurements of atopy and of airway hyperrespon siveness (AHR). Methods A large random sample of children aged 8-11 years was studied and 3 months later, their parents were also invited for study. Of the sample of 1655 children, both parents of 661 children were studied. In all subjects, respiratory illness history was measured by questionnaire, atopy by skin te sts and AHR by responsiveness to histamine. Results The odds ratio for a child to have AHR if either parent had the sam e condition was approximately 2.0, which was the same as the odds ratio for wheeze or diagnosed asthma in the presence of the same condition in either parent. The odds ratio for atopy was smaller (approximately 1.4, NS) but t he risk of a nonatopic child having AHR if the parent had AHR was 3.0 (P = 0.01). The correlation between weal size in the child and parent was poor a nd the severity of AHR in the child was only modestly correlated with the s everity of AHR in the parent (R = 0.51, P = 0.04). Conclusion The use of objective measurements did not strengthen the associa tion between atopic or asthmatic conditions in the parent and child, but di d suggest that atopy and AHR are inherited independently.