Occupational noise exposure and risk of incident stroke: a pooled study of five Scandinavian cohorts

Abstract

ObjectivesTo investigate the association between occupational noise exposure and stroke incidence in a pooled study of five Scandinavian cohorts (NordSOUND).MethodsWe pooled and harmonised data from five Scandinavian cohorts resulting in 78 389 participants. We obtained job data from national registries or questionnaires and recoded these to match a job-exposure matrix developed in Sweden, which specified the annual average daily noise exposure in five exposure classes (LAeq8h): <70, 70–74, 75–79, 80–84, ≥85 dB(A). We identified residential address history and estimated 1-year average road traffic noise at baseline. Using national patient and mortality registers, we identified 7777 stroke cases with a median follow-up of 20.2 years. Analyses were conducted using Cox proportional hazards models adjusting for individual and area-level potential confounders.ResultsExposure to occupational noise at baseline was not associated with overall stroke in the fully adjusted models. For ischaemic stroke, occupational noise was associated with HRs (95% CI) of 1.08 (0.98 to 1.20), 1.09 (0.97 to 1.24) and 1.06 (0.92 to 1.21) in the 75–79, 80–84 and ≥85 dB(A) exposure groups, compared with <70 dB(A), respectively. In subanalyses using time-varying occupational noise exposure, we observed an indication of higher stroke risk among the most exposed (≥85 dB(A)), particularly when restricting analyses to people exposed to occupational noise within the last year (HR: 1.27; 95% CI: 0.99 to 1.63).ConclusionsWe found no association between occupational noise and risk of overall stroke after adjustment for confounders. However, the non-significantly increased risk of ischaemic stroke warrants further investigation.

An updated job-exposure matrix for occupational noise: development and validation

“…The presented JEMs have already been used in several studies ( Eriksson et al 2018 ; Enoksson Wallas et al , 2019 ; Wallas et al 2018 , 2019 , 2020 ; Aarhus et al 2020 ; Eriksson et al 2021 ; Lissaker et al 2021 ; Thacher et al 2022 ) to study health effects from noise exposure such as cortisol levels, asthma, birth outcomes, and cardiovascular disease. We anticipate further use as an increasing number of epidemiological studies has shown health effects as a result of long-term exposure to noise ( An et al 2018 ; Kerns et al 2018 ; Brauner et al 2019 ; Liu et al 2022 ; Wei et al 2022 ).…”