Long-term exposure to air pollution and risk of insulin resistance: A systematic review and meta-analysis.

The effects of air pollution on metabolism have become a popular research topic, and a large number of studies had confirmed that air pollution exposure could induce insulin resistance (IR) to varying degrees, but the results were inconsistent, especially for the long-term exposures. The aim of the current study was to further investigate the potential effects of air pollution on IR. A systematic review and meta-analysis of four electronic databases, including PubMed, Embase, Web of Science and Cochrane were conducted, searching for relevant studies published before June 10, 2023, in order to explore the potential relationships between long-term exposure to air pollution and IR. A total of 10 studies were included for data analysis, including seven cohort studies and three cross-sectional studies. Four major components of air pollution, including PM 2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less), PM 10 (particulate matter with an aerodynamic diameter of 10 µm or less), NO 2 , and SO 2 were selected, and each analyzed for the potential impacts on insulin resistance, in the form of adjusted percentage changes in the homeostasis assessment model of insulin resistance (HOMA-IR). This systematic review and meta-analysis showed that for every 1 μg/m³ increase in the concentration of selected air pollutants, PM 2.5 induced a 0.40% change in HOMA-IR (95%CI: −0.03, 0.84; I² =67.4%, p = 0.009), while PM 10 induced a 1.61% change (95%CI: 0.243, 2.968; I² =49.1%, p = 0.001). Meanwhile, the change in HOMA-IR due to increased NO 2 or SO 2 exposure concentration was only 0.09% (95%CI: −0.01, 0.19; I² =83.2%, p = 0.002) or 0.01% (95%CI: −0.04, 0.06; I² =0.0%, p = 0.638), respectively. Long-term exposures to PM 2.5 , PM 10 , NO 2 or SO 2 are indeed associated with the odds of IR. Among the analyzed pollutants, inhalable particulate matters appear to exert greater impacts on IR. • Long-term exposure to air pollution is associated with the odds of insulin resistance. • Inhalable particulate matters have greater impacts on IR than other air pollutants. • Publication bias was considered in this meta-analysis and results seemed to be robust. [ABSTRACT FROM AUTHOR]