| Summary: | Cardiovascular disease is the leading cause of death worldwide. Recent evidence suggests associations between exposure to air pollution and community noise and cardiovascular disease mortality. While road traffic is a major common source for air pollution and community noise in urban areas, studies of their joint effects on the risk of cardiovascular disease have been limited.
Linked administrative databases from the British Columbia health insurance system were used to assemble a population-based cohort to investigate the independent and joint effects of traffic-related air pollution and community noise on coronary heart disease (CHD) mortality. The cohort included all residents aged 45-85 years who resided in metropolitan Vancouver, Canada, for at least 5 years at baseline (N~400,000). During a 4-year follow-up period, CHD death cases were identified from the provincial death registration database.
Distances from residences to major roads were first used as a surrogate for exposure to traffic-related pollution. Living close to major roads was associated with CHD mortality and changes in distances to major roads were associated with altered CHD mortality risk in an exposure-response fashion. Both traffic-related air pollution and noise could be responsible for these associations.
Subsequently, land use regression models were used to estimate residential exposure to major traffic-related air pollutants including black carbon, PM₂.₅, NO₂, and NO. Black carbon concentrations were associated with CHD mortality, with a clear exposure-response relationship. No robust associations were found with other air pollutants.
A noise prediction model was then used to estimate annual average community noise levels at each person’s residence. Community noise and black carbon were independently associated with CHD mortality: an interquartile range elevation in noise (6.6 dB(A)) and black carbon (0.97×10–⁵/m) was associated with a 6% (95% CI, 1-11%) and a 4% (95% CI, 1-8%) increase in coronary mortality, respectively. There was no discernable linear exposure-response relationship between community noise and CHD mortality.
Together, these analyses suggest that traffic-related fine particulate air pollution, indicated by black carbon, and traffic noise may both be responsible for observed associations between exposure to road traffic and cardiovascular disease.
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