Living near major traffic roads and risk of deep vein thrombosis.

BACKGROUND Particulate air pollution has been consistently linked to increased risk of arterial cardiovascular disease. Few data on air pollution exposure and risk of venous thrombosis are available. We investigated whether living near major traffic roads increases the risk of deep vein thrombosis (DVT), using distance from roads as a proxy for traffic exposure. METHODS AND RESULTS From 1995 through 2005, we examined 663 patients with DVT of the lower limbs and 859 age-matched controls from cities with population >15 000 inhabitants in Lombardia Region, Italy. We assessed distance from residential addresses to the nearest major traffic road using geographic information system methodology. The risk of DVT was estimated from logistic regression models adjusting for multiple clinical and environmental covariates. The risk of DVT was increased (odds ratio=1.33; 95% confidence interval, 1.03 to 1.71; P=0.03 in age-adjusted models; odds ratio=1.47; 95% confidence interval, 1.10 to 1.96; P=0.008 in models adjusted for multiple covariates) for subjects living near a major traffic road (index distance of 3 meters, 10th centile of the distance distribution) compared with those living farther away (reference distance of 245 meters, 90th centile). The increase in DVT risk was approximately linear over the observed distance range (from 718 to 0 meters) and was not modified after adjusting for BACKGROUND =0.008 for 10th versus 90th distance centile in models adjusting for area levels of particulate matter <10 mum in aerodynamic diameter in the year before diagnosis). CONCLUSIONS Living near major traffic roads is associated with increased risk of DVT.