Residential Exposure to Urban Air Pollution, Ankle–Brachial Index, and Peripheral Arterial Disease

BACKGROUND: Long-term exposure to particulate air pollution has been associated with increased cardiovascular disease. Biologic pathways for this association are not fully understood. METHODS: We examined the association of urban air pollution with atherosclerosis of the peripheral vascular bed, using baseline data (2000-2003) from 4348 participants in a population-based cohort study in the German Ruhr Area. Levels of annual fine particulate matter (PM2.5) exposure, derived from a dispersion and chemistry transport model, were assigned to the participants' home addresses. Residential traffic exposure was assessed by the distance between residence and major roads (federal and state highways). Using multiple regression analyses and controlling for individual level risk factors, we examined the association of PM2.5 and traffic with the ankle-brachial index and prevalence of peripheral arterial disease, defined as an index of less than 0.9 or a history of treatment for peripheral artery disease. RESULTS: Living within 101-200, 51-100, and 50 m of a major road was associated with an adjusted absolute decrease in ankle-brachial index of -0.015 (95% confidence interval CI = -0.030 to 0.0), -0.002 (-0.021 to 0.016) and -0.024 (-0.047 to -0.001), respectively. Stronger associations were seen in women, whereas no clear association was found in men. Individuals living within 50 m of a major road had an OR of 1.77 (1.01-2.1) for peripheral arterial disease compared with those living more than 200 m away. Associations with PM2.5 were inconsistent. CONCLUSIONS: This study adds to the evidence that long-term residential exposure to traffic is associated with atherosclerosis.