Associations of road traffic noise with carotid intima-media thickness and blood pressure: the Whitehall II and SABRE study cohorts

Abstract

Introduction Road traffic noise has been linked to increased risk of stroke for which hypertension and carotid intima-media thickness (cIMT) are risk factors. Although a link between traffic noise and hypertension has been established, there are fewer studies on blood pressure and none on cIMT. Methods The study population included participants of the Whitehall II and SABRE cohorts with measured carotid intima-media thickness, systolic (SBP) and diastolic blood pressure (DBP) and residential postcodes in Greater London (n=2592). Annual mean exposure to road traffic noise was estimated at each participant’s residential postcode centroid. We examined cross-sectional associations for day- and nighttime noise with cIMT, DBP and SBP. Results Mean age of the study population was 63 years (SD=7), mean daytime noise was 57.2 dB (SD=4.1). In the pooled model adjusted for cohort, sex, age, ethnicity, marital status, smoking, area-level deprivation and oxides of nitrogen a 10 dB increase in daytime noise was associated with a 9.9 µm (95% CI -6.8 to 26.6) increase in cIMT. Adjusted mean difference in cIMT was 11.6 µm (95% CI -9.5 to 32.6) higher among participants with daytime road traffic noise exposure >60 dB compared to those with noise levels <55 dB. In the pooled analysis, the association between daytime road traffic noise and SBP was also positive but imprecise: 0.43 mmHg (95% CI -1.36, 2.22) per 10 dB. No associations were observed for DPB. All results were similar for nighttime noise. Conclusions These data are consistent with a small positive, but non-significant association between day- and nighttime road traffic noise and cIMT after adjusting for individual-level confounders, area deprivation and air pollution. Associations between road traffic noise and blood pressure were largely null in this study population.