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Word count abstract: 250Running title: Traffic noise and carotid intima-media thickness
AcknowledgementWe thank all participating women and men in the Whitehall II Study and the SABRE study, as well as all Whitehall II research scientists, study and data managers and clinical and administrative staff and the SABRE study team who made the study possible. Objectives To examine cross-sectional associations for long-term exposure to night-time noise with cIMT, systolic blood pressure (SBP), diastolic blood pressure (DBP) and hypertension.Methods The study population consisted of 2592 adults from the Whitehall II and SABRE cohort studies living within Greater London who had cIMT, SBP and DBP measured. Exposure to night-time road traffic noise (A-weighted dB, referred to as dBA) was estimated at each participant's residential postcode centroid.Results Mean night-time road noise levels were 52dBA (SD=4). In the pooled analysis adjusted for cohort, sex, age, ethnicity, marital status, smoking, area-level deprivation and NOx there was a 9.1 µm (95% CI: -7.1, 25.2) increase in cIMT in association with 10dBA increase in night-time noise. Analyses by noise categories of 55-60dBA (16.2 µm, 95% CI: -8.7, 41.2), and >60dBA (21.2 µm, 95% CI: -2.5, 44.9) vs. <55dBA were also positive but non-significant, expect among those not using antihypertensive medication and exposed to >60dBA vs. <55dBA (32.6 µm, 95% CI: 6.2, 59.0). Associations for SBP, DPB and hypertension were close to null.Conclusions After adjustments, including for air pollution, the association between night-time road traffic noise and cIMT was only observed among non-medication users but associations with blood pressure and hypertension were largely null.