Exposure to particulate matters and risk of diabetes-related mortality: a systematic review and meta-analysis

Epidemiological evidence increasingly implicates ambient particulate matter (PM) as a contributor to diabetes progression and premature mortality; however, the strength and consistency of these associations remain uncertain. This systematic review and meta-analysis quantified the relationship between exposure to major PM fractions-particularly PM_2.5 and PM₁₀-and the risk of diabetes-related mortality in adult populations.

Following PRISMA and MOOSE guidelines, five databases were searched through September 30, 2025. Eligible observational studies assessed long- or short-term exposure to ambient PM and reported quantitative estimates for diabetes-associated deaths. Effect sizes were pooled using random-effects models and expressed as relative risk (RR) per 10 µg/m³ increment in PM concentration. Subgroup and meta-regression analyses explored sources of heterogeneity.

Thirty-six studies (41 datasets) were included. Pooled analysis showed a significant positive association between PM_2.5 exposure and diabetes-related mortality (RR = 1.123; 95%CI: 1.099-1.147; I² = 95.3%). The effect was stronger for long-term exposure (RR = 1.296; 95%CI: 1.197-1.395) and prospective cohorts (RR = 1.327; 95%CI: 1.189-1.466). PM₁₀ was also associated with increased risk, though with smaller magnitude (RR = 1.021; 95%CI: 1.007-1.035; I² = 81.7%). Meta-regression confirmed exposure duration as a significant modifier (p = 0.014).

Both fine (PM_2.5) and coarse (PM₁₀) particulate matter are significantly associated with increased diabetes-related mortality, with the strongest and most consistent effects observed for chronic PM_2.5 exposure. These findings highlight the metabolic health burden of air pollution and underscore the importance of stringent air-quality standards to reduce premature diabetes deaths globally.