Long-Term Exposure to Noise and the Development of Diabetes and Hypertension in Toronto, Canada: A Cohort Study

摘要

Background: Exposure to noise has been linked to cardiovascular disease risk factors, such as elevated blood pressure and glucose dysregulation. However, epidemiologic evidence linking road traffic noise and cardiovascular disease and its risk factors remains scarce in North America. We assessed associations between road traffic noise and the incidence of diabetes and hypertension in Toronto, Canada, which is the fourth largest city in North America. Methods: We conducted a population-based cohort study of ～1 million individuals, who were aged 35-100 years and long-term residents of Toronto. Noise levels were derived using SoundPLAN Acoustics software as equivalent A-weighted sound pressure level from traffic for nighttime (LAeqNight) and 24-hour day (LAeq24h). Three-year average levels of noise were assigned to subjects' annual residential postal codes. To estimate the association between noise and outcomes, we used random-effect Cox proportional hazards models adjusting for personal and area-level characteristics. We conducted sensitivity analyses, including further adjusting for comorbidities and air pollution (ultrafine particles and nitrogen dioxide). We also fitted three-level categorical variables of noise by 5 dBA increments (<45 dBA and <55 dBA as the reference levels for LAeqNight and LAeq24h, respectively). Results: From 2001 to 2015, each interquartile range increase in LAeqNight (10.0 dBA) was associated with the incidence of diabetes (HR 1.08; 95% CI: 1.07-1.09) and hypertension (HR 1.02; 95% CI: 1.01-1.03). We found similar results with LAeq24h. These results were robust to all sensitivity analyses conducted. For diabetes, when considering noise exposure as a categorical variable, exposure to the highest levels of LAeqNight and LAeq24h was associated with HRs of 1.15 and 1.12, respectively, compared to the lowest levels. Conclusions: Exposure to road traffic noise was associated with increased incidence of diabetes and hypertension in Toronto.