Long-term exposure to traffic noise and traffic-related air pollution and coronary heart disease mortality

Abstract

The authors investigated the independent and joint effects of urban noise and trafficrelated air pollution on the risk of coronary heart disease (CHD) mortality. This population-based cohort study included a 5-year exposure period and a 4-year follow-up period. All residents aged 45-85 years who resided in metropolitan Vancouver during the exposure period and without known CHD at baseline were included (n = 445,868). Individual exposures to noise and traffic-related air pollutants (NO, NO2, black carbon, PM2.5) were estimated at subjects' residences using a detailed noise prediction model and land use regression models, respectively. CHD deaths were identified from provincial death registration database. After adjusting for covariates and coexistent traffic-related air pollutants or noise, an interquartile-range (IQR) increase in residential noise was associated with 6 % (95 % CI: 1-11 %) increase in CHD mortality (IQR increase in black carbon, 4%; 95%-CI: 1 -8%). Subjects in the highest noise decile had a 22 % (95% CI: 4-43 %) increase in CHD mortality compared with those in the lowest decile. Co-exposure to higher levels of traffic noise and black carbon was associated with a substantially greater risk of coronary mortality; relative risk for CHD in top decile of noise and top quartile of black carbon was 1.45 (95 %-CI 1.14 -1.85). These results suggest independent effects of noise and traffic-related air pollution on CHD mortality.