Occupational noise exposure and tinnitus: the HUNT Study.

ABSTRACT

OBJECTIVE: We aimed to assess the association between occupational noise exposure and tinnitus. Further, to assess whether the association depends on hearing status. DESIGN: In this cross-sectional study, tinnitus (>1 h daily) was regressed on job exposure matrix (JEM)-based or self-reported occupational noise exposure, adjusted for confounders. STUDY SAMPLE The 14,945 participants (42% men, 20-59 years) attended a population-based study in Norway (HUNT4, 2017-2019). RESULTS: JEM-based noise exposure, assessed as equivalent continuous sound level normalised to 8-h working days (LEX 8 h), over the working career or as minimum 5 years ≥85 dB) was not associated with tinnitus. Years of exposure ≥80 dB (minimum one) was not associated with tinnitus. Self-reported high noise exposure (>15 h weekly ≥5 years) was associated with tinnitus overall and among persons with elevated hearing thresholds (prevalence ratio (PR) 1.3, 1.0-1.7), however not statistically significantly among persons with normal thresholds (PR 1.1, 0.8-1.5). CONCLUSIONS: Our large study showed no association between JEM-based noise exposure and tinnitus. This may to some extent reflect successful use of hearing protection. High self-reported noise exposure was associated with tinnitus, but not among normal hearing persons. This supports that noise-induced tinnitus to a large extent depends on audiometric hearing loss.