Associations of long-term exposure to ambient nitrogen dioxide with indicators of diabetes and dyslipidemia in China: a nationwide analysis

Abstract Background The associations between ambient NO2 and diabetes and dyslipidemia have been controversial, and data is especially lacking in developing countries. Objective This study aimed to assess the associations of long-term exposure to NO2 with diabetes and dyslipidemia in China. Methods We conducted a cross-sectional study including 13,013 participants from the China Health and Retirement Longitudinal Study. The annual average concentrations of NO2 were estimated based on land-use regression, satellite measurements, and universal kriging. We applied logistic regression models to evaluate the associations of NO2 with diabetes and dyslipidemia, and linear regression models to assess the associations with blood biomarkers. Results A total of 1,933 diabetes cases (14.85%) and 1,935 (14.87%) dyslipidemia cases were identified. Significant associations were observed between NO2 and risk of diabetes and dyslipidemia independent of PM2.5 and O3. For an interquartile range (IQR) increase in NO2 (12.39 μg/m3), we observed a 13% [odds ratio (OR): 1.13; 95% confidence interval (CI): 1.01, 1.26] increased risk of diabetes, 1.48% (95%CI: 0.51%, 2.46%) increase in glucose, 0.74% (95%CI: 0.19%, 1.29%) increase in glycosylated hemoglobin (HbA1c), 17% (OR: 1.17; 95% CI: 1.05, 1.31) increased risk of dyslipidemia, 4.62% (95%CI: 2.49%, 6.79%) increase in triglyceride, and a decrease of 2.96% (95%CI: 2.13%, 3.79%) in high-density lipoprotein. The associations of NO2 with glucose disorders were stronger among smokers. Conclusions Our study indicated long-term exposure to NO2 might contribute to the development of diabetes and dyslipidemia, and the associations were potentially independent of O3 and PM2.5.