Long-Term Exposure to Ambient Air Pollution and Subclinical Cerebrovascular Disease in NOMAS (the Northern Manhattan Study)

Background and Purpose-Long-term exposure to ambient air pollution is associated with higher risk of cardiovascular disease and stroke. We hypothesized that long-term exposure to air pollution would be associated with magnetic resonance imaging markers of subclinical cerebrovascular disease. Methods-Participants were 1075 stroke-free individuals aged >= 50 years drawn from the magnetic resonance imaging subcohort of the Northern Manhattan Study who had lived at the same residence for at least 2 years before magnetic resonance imaging. Cross-sectional associations between ambient air pollution and subclinical cerebrovascular disease were analyzed. Results-We found an association between distance to roadway, a proxy for residential exposure to traffic pollution, and white matter hyperintensity volume; however, after adjusting for risk factors, this relationship was no longer present. All other associations between pollutant measures and white matter hyperintensity volume were null. There was no clear association between exposure to air pollutants and subclinical brain infarcts or total cerebral brain volume. Conclusions-We found no evidence that long-term exposure to ambient air pollution is independently associated with subclinical cerebrovascular disease in an urban population-based cohort.