[Disparity of asthma prevalence in Chinese schoolchildren is due to differences in lifestyle factors].
OBJECTIVE
To investigate the environmental lifestyle risk factors which may explain the disparity of asthma prevalence in the Chinese population.


METHODS
In a cross-sectional study, 10 902 schoolchildren were recruited from Hong Kong (n = 3110), Beijing (n = 4277), and Guangzhou (n = 3565) using the ISAAC Phase II protocol. The average age of the children among three cities was 10.1-10.4 years and 50%-53% were male. Each subject was given an ISAAC Phase II questionnaire to be completed by the parents or guardians. Random subgroups of at least 1000 children from each city, added up to 3479 children underwent skin-prick testing. The sensitivity to eight common aeroallergens was assessed. Logistic regression analysis was used to determine the environmental and lifestyle risk factors for asthma and atopy.


RESULTS
The prevalence of wheezing in the past 12 months (Hong Kong, 5.8%; Beijing, 3.8%; Guangzhou, 3.4%) was significantly higher in schoolchildren from Hong Kong than that from the Mainland of China (OR 1.64, 95% CI 1.35-1.99). Multivariate logistic regression analyses revealed that the use of gas cooking (OR 2.08, 95% CI 1.32-3.26), foam pillow (OR 1.94, 95% CI 1.19-3.16), and house dampness (OR 1.84, 95% CI 1.25-2.71) were significant risk factors for "current wheezing". The use of cotton quilt (OR 0.70, 95% CI 0.56-0.87), breast-feeding (OR 0.79, 95% CI 0.66-0.96), and attendance of daycare (OR 0.73, 95% CI 0.59-0.88) were protective factors against "current wheezing". When a summary measure of these variables was introduced into a regression model, the Mainland residency was no longer associated with "current asthma" or "current wheezing" suggesting that either these factors or other unmeasured factors associated with above factors are responsible for the lower prevalence of asthma in the Mainland of China.


CONCLUSIONS
Several environmental and lifestyle factors represented characteristic of life in Mainland of China, including breast feeding, attendance of daycare, use of cotton quilt, use of pillow other than foam pillow, use of cooking fuel other than gas, and the absence of damp spots on the walls or ceiling, were the significant risk factors contributed to the disparity of asthma prevalence in children from Hong Kong and the Mainland of China.
Wang
Hong-yu
HY
Department of Allergy, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital, Guangzhou Medical College, Guangzhou 510120, China.
Chen
Yu-zhi
YZ
Ma
Yu
Y
Wong
Gary W K
GW
Lai
Christopher K W
CK
Zhong
Nan-Shan
NS
D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D002648:Child; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D054624:Health Status Disparities; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D015995:Prevalence; D012135:Respiratory Sounds; D012307:Risk Factors; D012882:Skin Tests; D011795:Surveys and Questionnaires