The combined effects of exposure to multiple PM 2.5 components on overweight and obesity in middle-aged and older adults: a nationwide cohort study from 125 cities in China

The prevalence of overweight or obesity increased rapidly over the past decades in most countries, including China. However, little evidence exists about the effects of long-term exposure to PM 2.5 components on overweight or obesity, particularly in developing countries. We measured different weight stages according to body mass index (BMI), and investigated the effects of exposure to PM 2.5 components (ammonium [ NH_4^+ ], sulfate [ SO_4^2- ], nitrate [ NO_3^- ], black carbon and organic matter) on different BMI levels in middle-aged and elderly people of China. Our study explored the effects of single and multiple air pollution exposures on overweight and obesity by using the Generalized Linear Model and Quantile g-Computation model (QgC). This study found a significantly positive association between five PM 2.5 components and overweight/obesity. In the QgC model, there was still a positive association between multiple exposure to PM 2.5 components and overweight when all PM 2.5 components were considered as a whole. In addition, males, the elderly, and urban residents were also more sensitive to five PM 2.5 components.