Road traffic noise and hypertension - Accounting for the location of rooms

Objective: The association between the exposure to road traffic noise and the prevalence of hypertension was assessed accounting for background air pollution and the location of rooms with respect to the road. Methods: A cross-sectional study was carried out inviting all subjects aged 35-74 years for participation that lived on 7 major trunk roads in 3-4 storey terraced apartment buildings and in parallel side streets that were completely shielded from noise due to the rows of houses along the major roads. The study was performed on 1770 subjects that did not have a self-reported medical doctor diagnosis of hypertension before they moved into their current residence. Noise levels at the facade of the front and the rear side of the houses were drawn from available noise maps of the area. A large set of covariates were considered to adjust the results for confounding. Results: Significant increases between road traffic noise and hypertension were found with respect to the 24 h A-weighted average noise indicator L-DEN. The adjusted odds ratio (OR) per noise level increment of 10 dB(A) was 1.11 (95% confidence interval (CI): 1.00-1.23). Stronger significant estimates of the noise effect were found in subjects with long residence time (OR = 1.20, CI=1.05-1.37), and with respect to the exposure of the living room during daytime (OR=1.24, CI=1.08-1.41) compared with the exposure of the bedroom during night-time (OR=0.91, CI=0.78-1.06). Conclusion: Chronic exposure to road traffic noise is associated with an increased risk of high blood pressure. Daytime noise exposure of the living room had a stronger impact on the association than night-time exposure of the bedroom. (C) 2014 Elsevier Inc. All rights reserved.