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 (CHRLS). The annual average concentrations of NO₂ were estimated based on the residential addresses of participants. 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 1933 diabetes cases (14.85%) and 1935 (14.87%) dyslipidemia cases were identified. Significant associations were observed between NO₂ and risk of diabetes and dyslipidemia independent of PM_2.5 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 PM_2.5.

Keywords: Air pollution; Diabetes; Dyslipidemia; Glucolipid metabolism; Nitrogen dioxide.