Long-term effects of ambient PM2.5 constituents on metabolic syndrome in Chinese children and adolescents

Metabolic syndrome (MetS) is considered a main public health issue as it remarkably adds the risk of cardiovascular disease, leading to a heavy burden of disease. There is growing evidence linking fine particulate matter (PM2.5) exposure to MetS. However, the influences of PM2.5 constituents, especially in children and adolescents, remain unclear. Our study was according to a national analysis among Chinese children and adolescents to examine the associations between long-term exposure to PM2.5 main constituents and MetS. A total of 10,066 children and adolescents aged 10-18 years were recruited in 7 provinces in China, with blood tests, health exams, and questionnaire surveys. We estimated long-term exposures to PM2.5 mass and its five constituents, containing black carbon (BC), organic matter (OM), inorganic nitrate (NO3-), sulfate (SO42-), and soil particles (SOIL) from multi-source data fusion models. Mixed-effects logistic regression models were used with the adjustment of a variety of covariates. In the surveyed populations, 2.9% were classified as MetS. From the single-pollutant models, we discovered that long-term exposures to PM2.5 mass, BC, OM, NO3-, as well as SO42-, were significantly associated with the prevalence of MetS, with odds ratios (ORs) per 1 mu g/m(3) that were 1.02 (95% confidence interval (CI): 1.01, 1.03) for PM2.5 mass, 1.24 (95% CI: 1.14, 1.35) for BC, 1.07 (95% CI: 1.04, 1.11) for OM, 1.09 (95% CI: 1.04, 1.13) for NO3-, and 1.14 (95% CI:1.04, 1.24) for SO42-. The influence of BC on the prevalence of MetS was robust in both the multi-pollutant model and the PM2.5-constituent joint model. The paper indicates long-term exposure to PM2.5 mass and specific PM2.5 constituents, particularly for BC, was significantly associated with a higher MetS prevalence among children and adolescents in China. Our results highlight the significance of establishing further regulations on PM2.5 constituents.