Effects of ambient particulate matter on fasting blood glucose: A systematic review and meta-analysis.

Studies have found that ambient particulate matter (PM) affects fasting blood glucose. However, the results are not consistent. We conducted a systematic review and meta-analysis to determine the relationship between PM with an aerodynamic diameter of 10 μm or less (PM10) and PM with an aerodynamic diameter of 2.5 μm or less (PM2.5) and fasting blood glucose. We searched PubMed, Web of Science, the Wanfang Database and the China National Knowledge Infrastructure up to April 1, 2019. A total of 24 papers were included in the review, and 17 studies with complete or convertible quantitative information were included in the meta-analysis. The studies were divided into groups by PM size fractions (PM10 and PM2.5) and length of exposure. Long-term exposures were based on annual average concentrations, and short-term exposures were those lasting less than 28 days. In the long-term exposure group, fasting blood glucose increased 0.10 mmol/L (95% CI: 0.02, 0.17) per 10 μg/m3 of increased PM10 and 0.23 mmol/L (95% CI: 0.01, 0.45) per 10 μg/m3 of increased PM2.5. In the short-term exposure group, fasting blood glucose increased 0.02 mmol/L (95% CI: -0.01, 0.04) per 10 μg/m3 of increased PM10 and 0.08 mmol/L (95% CI: 0.04, 0.11) per 10 μg/m3 of increased PM2.5. Further prospective studies are needed to explore the relationship between ambient PM exposure and fasting blood glucose.