Prevalence of respiratory and atopic disorders in Chinese schoolchildren

Background Epidemiological surveys have shown that the prevalence of asthma in the Asian population is relatively low. Within the Chinese population, schoolchildren from Hong Kong were found to have the highest rate of asthma . Objective To compare the prevalence of respiratory and atopic disorders, an d to assess the role of atopy in the development of asthma, in Chinese scho olchildren from Hong Kong, Beijing and Guangzhou. Methods Community-based random samples of schoolchildren aged 9-11 years fr om three Chinese cities (Hong Kong, Beijing and Guangzhou) were recruited f or study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Subjects were studied by parental questionnaire s (n = 10902), skin-prick tests (n = 3479) and skin examination (n = 3479). Results The prevalence rates of current wheeze, speech limiting wheeze, rhi noconjunctivitis and flexural dermatitis were significantly more common in Hong Kong than in Beijing or Guangzhou. The atopy rate was also higher in H ong Kong (41.2%) than in Beijing (23.9%) or Guangzhou (30.8%). Atopy was st rongly correlated with current wheeze (OR 7.74; 95% CI = 5.70-10.51). Subgr oup analyses of children from Hong Kong revealed that children born in main land China who had subsequently migrated to Hong Kong had a significantly l ower rate of allergic symptoms and atopy than those children born in Hong K ong. Conclusion Using a standardized written questionnaire along with a skin pri ck test and skin examination, we confirmed that the prevalence of asthma, a llergic diseases and atopy was highest in schoolchildren from Hong Kong. At opic sensitization is an important factor associated with asthma in Chinese children.