Abstract
BACKGROUND: The association between ambient air pollution and glycolipid metabolic disorders (GMDs, including diabetes mellitus and dyslipidemia) is still not well understood, especially when it comes to the different effects of long-term vs short-term exposure and the sources of pollutants (indoor or outdoor). AIM: To look at how outdoor particulate matter (PM(1), PM(2.5), PM(10)) and ozone (O(3)), as well as indoor pollutants from solid fuels, are related to the risk of developing GMDs in a cohort that represents the national population. METHODS: We used a longitudinal cohort design to look at how different time periods of air pollution exposure (long-term: 5-year averages; short-term: 1-year averages) affect the incidence of GMDs in middle-aged and elderly adults. Multivariable logistic regression models, which took into account key factors such as age, sex, and smoking status, were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Our study found that exposure to air pollution (1 μg/m(3)) has different effects on GMDs. Long-term exposure to outdoor pollutants like PM(1), PM(2.5), PM(10), and O(3) consistently increased the risk of diabetes (PM(1): OR = 1.106, 95%CI: 1.018-1.205; PM(2.5): OR = 1.038, 95%CI: 1.007-1.071; PM(10): OR = 1.023, 95%CI: 1.004-1.043) and dyslipidemia (PM(1): OR = 1.150, 95%CI: 1.064-1.249; PM(2.5): OR = 1.053, 95%CI: 1.023-1.086; PM(10): OR = 1.032, 95%CI: 1.014-1.052). Short-term exposure showed even stronger associations, particularly for PM(1) with dyslipidemia (OR = 1.078, 95%CI: 1.044-1.114) and PM(1) with diabetes (OR = 1.047, 95%CI: 1.007-1.089). Notably, certain components of PM(2.5) - chloride (Cl(-)), ammonium (NH(4) (+)), sulfate (SO(4) (2-)), and nitrate (NO(3) (-)) - showed a dose-dependent relationship with both conditions (for example, Cl(-): Diabetes OR = 1.797 per 1 μg/m(3), 95%CI: 1.086-2.991; dyslipidemia OR = 2.627, 95%CI: 1.728-4.012). However, neither long-term nor short-term exposure to indoor solid fuel pollutants was significantly associated with diabetes (long-term OR = 1.034, 95%CI: 0.801-1.333; short-term OR = 0.970, 95%CI: 0.774-1.209) or dyslipidemia (short-term OR = 1.159, 95%CI: 0.967-1.386). CONCLUSION: This national cohort study shows that outdoor air pollution - particularly PM(1), PM(2.5), and their chemical components - is an important environmental factor contributing to GMDs, with long-term exposure showing greater metabolic toxicity than short-term exposure. The lack of association between indoor solid fuel pollutants and GMDs underscores the urgent need for targeted interventions to improve outdoor air quality and reduce metabolic risks at the population level.