A 10 city cross-sectional questionnaire survey in China: A preliminary understanding of the riddles behind the rapid increased prevalence of children’s asthma

Abstract

Background-In the past two decades, China is experiencing the most rapid and dramatic changes in indoor environment exposure. Coincidently, the prevalence rate of asthma among children increased by 10%. Aims-To understand associations between the home environment in China and asthma and allergy among Chinese children. Methods-China, Children, Homes, Health (CCHH), Phase I study, is a cross-sectional questionnaire survey including 48219 children aged 1-8 years old in 10 major cities (Beijing, Changsha, Chongqing, Harbin, Nanjing, Shanghai, Taiyuan, Urumqi, Wuhan, Xi’an) of China during 2010-2011. The questionnaire used included the core questions in the International Study of Asthma and Allergies in Childhood (ISAAC) and validated questions regarding housing, life habits and outdoor environment, which has been adapted to Chinese customs and building characteristics, from the questions used in Sweden, Denmark, Bulgaria, USA, Taiwan, Singapore, and South Korea. Results-The average prevalence of asthma across China was 6.8% (range 1.7%-9.8%), hay fever 8.6% (2.2%-11.6%), current wheeze 19.2% (13.9%-23.7%), current rhinitis 41.3% (24.0%-45.5%), current eczema 12.1% (4.8%-15.8%). Rates of visible mold on indoor surfaces ranged from 4% (Xi’an; Beijing) to 12% (Harbin), condensation on windowpane in winter from 14.3% (Chongqing) to 32.2% (Nanjing), moldy odor from 0.4% (Nanjing) to 1.9% (Harbin). On average, 59% of families had environmental tobacco smoke exposure. The asthma prevalence was positively associated with the economic status indexed by Gross Domestic Production per capita of a city, but not with ambient air pollution. Conclusions- The data and information collected in this study will be helpful in finding the associations between children’s health and indoor environment exposures.