Obesogenic environmental factors of adult obesity in China: a nationally representative cross-sectional study

The prevalence of obesity is still rising among Chinese adults and may be attributed to environmental factors, which, however, has only been examined in western countries before. This study aimed to estimate associations between obesogenic environments and adult obesity in China, on the basis of the official 2013-4 nationally representative survey. General and abdominal obesity were defined by body mass index and waist circumference, respectively, according to both the Chinese and international criteria. The mean summer/winter temperature in provinces, the mean fine particulate matter (PM2.5) concentration, gross domestic product per capita, and education level in districts/counties, and the densities of fast-food restaurants, full-service restaurants, grocery stores, and supermarkets in subdistricts/towns were calculated. Five-level logistic regression models were used to estimate their associations with obesity, also in urban and rural regions separately. Both general and abdominal obesity in men were associated with the highest PM2.5 concentration, summer temperature, and density of full-service restaurants and grocery stores, as well as the lowest winter temperature. These associations were also observed in women except for summer temperature and density of full-service restaurants with abdominal obesity. Some associations varied by urban-rural regions. Also, the higher regional education level was associated with general and abdominal obesity in men. Additionally, obesity was associated with the increasing number of coexisting obesogenic environmental factors. Our findings call for more attention to citizens living in certain environments in China, such as cold winters and with more full-service restaurants and grocery stores. This is the first national, comprehensive obesogenic environment study in China, which generated evidence-based hypotheses for future longitudinal research and interventions on obesogenic environments in China.