Association between Air Pollution and Type 2 Diabetes Mellitus in Developing Countries: A Systematic Review and...

Objective In recent years, many studies have reported that air pollution is a risk factor for type 2 diabetes mellitus (T2DM). The aim of this systematic review and meta-analysis is to summarize the evidence about the association between exposure to air pollution and T2DM in developing countries. Methods The databases, including PubMed, EMBASE and Web of Science, were systematically searched for studies published up to 31 March 2022. Studies about the association between air pollution and T2DM prevalence or incidence in developing countries were included. The odds ratio (OR) was used as effect estimate. We synthesized the included studies in the meta-analysis. Results We included 8 cross-sectional studies and 8 cohort studies, all conducted in developing countries. Meta-analysis of 8 studies on PM_2.5 (particulate matter ≤ 2.5 μm in diameter) showed that T2DM prevalence was significantly associated with PM_2.5 exposure (OR=1.12; 95% CI: 1.07, 1.17; P<0.001). The association between air pollutants and T2DM incidence was not estimated due to the limited relevant studies. Conclusions The exposure to PM_2.5 would be positively associated with an increased prevalence of T2DM in developing countries. Some effective measures should be taken to reduce air pollutant exposure in people who are vulnerable to diabetes.