Working in preschool increases the risk of hearing-related symptoms: a cohort study among Swedish women

Sofie Fredriksson,Kerstin Persson Waye,Lennart Magnusson,Kjell Torén,Jeong-Lim Kim,Kim Kähäri,Mia Söderberg

doi:10.1007/s00420-019-01453-0

Abstract

PurposeTo assess whether working in preschools increases the risk of hearing-related symptoms and whether age, occupational noise, and stressful working conditions affect the risk.MethodsQuestionnaire data on hearing-related symptoms were analysed in women aged 24–65 (4718 preschool teachers, and 4122 randomly selected general population controls). Prevalence and risk ratio (RR) of self-reported hearing loss, tinnitus, difficulty perceiving speech, hyperacusis and sound-induced auditory fatigue were assessed by comparing the cohorts in relation to age and self-reported occupational noise and stressful working conditions (effort–reward imbalance and emotional demands). RR was calculated using log-binomial regression models adjusted for age, education, income, smoking, hearing protection, and leisure noise. Incidence rates and incidence rate ratios (IRR) were calculated for retrospectively reported onset of all symptoms except sound-induced auditory fatigue.ResultsCompared to the controls, preschool teachers had overall more than twofold RR of sound-induced auditory fatigue (RR 2.4, 95% confidence interval 2.2–2.5) and hyperacusis (RR 2.3, 2.1–2.5) and almost twofold for difficulty perceiving speech (RR 1.9, 1.7–2.0). Preschool teachers had a threefold IRR of hyperacusis (IRR 3.1, 2.8–3.4) and twofold for difficulty perceiving speech (IRR 2.4, 2.2–2.6). Significantly although slightly less increased RR and IRR were observed for hearing loss and tinnitus. RR and IRR were generally still increased for preschool teachers when stratified by age and occupational exposure to noise and stress.ConclusionsThis large cohort study showed that working as preschool teacher increases the risk of self-reported hearing-related symptoms, indicating a need of preventative measures.

Highlights

The majority of research on occupational noise has been performed in traditionally male-dominated and high levelexposure occupations such as industry, mining and construction (Concha-Barrientos et al 2004; Kurmis and Apps 2007; Lie et al 2016)
These results are in line with previous studies showing that preschool teachers are exposed to high sound levels in preschool (Persson Waye et al 2010; Sjödin et al 2012; Gerhardsson and Nilsson 2013) and have an increased risk of stressful working conditions compared to nonhuman service occupations (Wieclaw et al 2006)
Our current results are in line with a previous study in which we found increased odds ratios of sound-induced auditory fatigue among obstetrical personnel in relation to self-reported occupational noise exposure, noise annoyance, and to some degree work-related stress, but not in relation to age (Fredriksson et al 2015)

Summary

Introduction

The majority of research on occupational noise has been performed in traditionally male-dominated and high levelexposure occupations such as industry, mining and construction (Concha-Barrientos et al 2004; Kurmis and Apps 2007; Lie et al 2016). Most of these studies have assessed hearing loss measured using pure tone audiometry as the main outcome. The average sound level indoors in Swedish preschools has been measured close to the lower action level 80 dBA Leq (Persson Waye et al 2010; Sjödin et al 2012). The action level is regulated by the Swedish Work Authorities to reduce the risk of noiseinduced auditory disorder among employees

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