Venous Thrombosis and Air Pollution: A Systematic Review and Meta-Analysis of 1.4 Million Adult Patients

The comprehensive relation between air pollutants and venous thrombosis is currently not available.

The Web of Science, PubMed, Scopus, and Embase databases were searched up to July 1, 2025, for population-based studies of the associations of air pollutants with venous thrombotic events, including deep vein thrombosis (DVT), pulmonary embolism (PE), or both (venous thromboembolism [VTE]). The relative risks (RRs) and corresponding 95% confidence intervals (95% CIs) were derived using a random-effects meta-analysis. A total of 23 studies were identified from an initial screening of 944 articles, which incorporated more than 1.4 million venous thrombotic events (DVT only, PE only, or both [VTE]). Meta-analysis showed that occurrence of venous thrombosis was positively associated with long-term particles exposures, but not with short-term particles exposures or with any metrics of gaseous pollutants. Specifically, the increased risk of VTE was associated with a 10 μg/m³ increase in PM_2.5 (RR 1.0804, 95% CI: 1.0015-1.1656) and PM₁₀ (RR 1.0369, 95% CI: 1.0260-1.0479) during average pollutant concentrations of one year or more. Subgroup analyses further indicated that the associations with PM_2.5 remained statistically significant for DVT and among older participants. We estimated that reducing the annual average of PM_2.5 concentrations to meet the World Health Organization Air Quality Guideline of 5 μg/m³ would prevent 98,233 venous thrombotic events globally.

This analysis suggest that particulate matter air pollution might be a risk factor for venous thrombosis, highlighting that environmental policies to reduce population exposure levels may mitigate the burden of venous thrombotic events.