ABSTRACT
<p><b>OBJECTIVE</b>To discuss the related impact of genetic factors in the incidence of bronchial asthma (BA) and allergic rhinitis (AR) in Nantong region, China.</p><p><b>METHODS</b>By random sampling method, investigation and research on the incidence of genetic epidemiology were carried out in the population of 95 300 on AR and BA.</p><p><b>RESULTS</b>The rate of patients with allergic rhinitis with asthma was 25.92% (296/1142), the rate of asthma patients with allergic rhinitis was 40.49% (296/731). The prevalences of AR complicated with BA were 8.19% (280/3418), 3.08% (154/5002) and 3.16% (85/2687) in the first-, second-and third-degree relatives of the probands respectively, while the prevalences of BA complicated with AR were 15.81% (466/2947), 4.61% (229/4967) and 2.51% (134/5345) in the first-, second- and third-degree relatives of the probands respectively, higher than those in the controls (P < 0.05). The weighted mean heritability of AR in BA patients was 94.2% ± 1.9%, while the weighted mean heritability of BA in AR patients was 81.8% ± 2.1%, more than 60%, suggesting that both AR and BA were relevant with genetics.</p><p><b>CONCLUSIONS</b>The incidence of BA and AR has obvious relevance, supporting the theory that the two diseases are an united airway disease and relevant with polygene heredity.</p>