Article Text
Abstract
Objectives The authors investigated associations between cardiovascular mortality and air pollution and noise together.
Methods Data from an ongoing Dutch cohort study on diet and cancer (NLCS, 120,852 subjects; follow-up 1987-1996) were used. Cox proportional hazard analyses were conducted for the association between cardiovascular mortality and exposure to black smoke (BS), traffic intensity on the nearest road and road traffic noise at the home address.
Results The correlations between traffic noise and background BS, and traffic intensity on the nearest road were moderate at: 0.24 and 0.30 respectively. Traffic intensity was associated with cardiovascular mortality, with highest relative risk (95% confidence interval) for ischemic heart disease (IHD) mortality: 1.11 (1.03 - 1.20) (increment 10,000 mvh/24h). Relative risks for BS concentrations were elevated for cerebrovascular (1.39 (0.99 - 1.94)) and heart failure mortality (1.75 (1.00 - 3.05) (increment 10 μg/m3). These associations were insensitive to adjustment for traffic noise. There was an excess of cardiovascular mortality in the highest noise category (>65 dB(A)), with elevated risks for IHD (1.15 (0.86 - 1.53) and heart failure mortality (1.99 (1.05 - 3.79). After adjustment for BS and traffic intensity noise risks became unity for IHD mortality and slightly reduced for heart failure mortality.
Conclusions Associations between BS concentrations and traffic intensity on the nearest road with specific cardiovascular causes of death were not explained by traffic noise in this study.