Environmental risk factor assessment: A multilevel analysis of childhood asthma in China

Background: Rapid changes in socioeconomic environment and their diverse patterns in China raise a question: how socio-environmental factors affect childhood asthma in China. We performed a multilevel analysis based on a 2005 national survey to understand the association between environmental factors and asthma, and to provide insights on developing prevention strategies. Methods: A multi-center, cross-sectional survey was conducted in 2018 school-aged children chosen from eight Chinese cities. Children of 6-13 years old were chosen randomly from schools of 39 centers in 8 cities. The multilevel analysis was made to assess both individual-level and city-level risk factors. The effect of gross domestic product (GDP) was further investigated by analysis of the factors. Results: Analysis of city-level environmental factors showed that GDP [adjusted odds ratio (OR)=1.88], particulate matter with aerodynamic diameter ≤10 μm (PM₁₀) (adjusted OR=1.37), and average humidity (adjusted OR=1.33) were strong risk factors. Further analysis of the factors decomposed GDP into two major factors, the first represented by urban construction, energy consumption, nitrogen dioxide concentration, and the second represented by health-system coverage. This suggested that the negative effects of GDP outweighed its positive effects on asthma. Conclusions: The prevalence of childhood asthma varies significantly in the eight Chinese cities. Socioenvironmental factors such as GDP, PM₁₀ and average humidity are strong risk factors controlling individual attributes, suggesting that balance is needed between public health and economic development in China.