Association between shift work and hearing loss: The Dongfeng-Tongji cohort study

The association between shift work and hearing loss is unclear. We aimed to evaluate this association in a Chinese population independently and in combination with occupational noise. A total of 11,196 participants of the Dongfeng-Tongji cohort study were included. Shift work was self-reported and hearing loss was defined as a pure-tone mean of 25 dB or higher at 0.5, 1, 2, and 4 kHz in any ear. The Robust Poisson method were used to assess the relationship between shift work and hearing loss, and the prevalence ratios (PRs) were calculated. Compared to individuals who reported no shift work, the PRs of bilateral hearing loss were significantly higher for a shift work duration of fewer than 10 years in women, (PR = 1.024, 95% confidence interval [CI] = 1.002-1.053), but not in men (PR = 1.016, 95% confidence interval [CI] = 0.998-1.035). The association between short duration of shift work and bilateral hearing loss was just statistically significant in women when those with occupational noise exposure were excluded (PR = 1.067, 95%CI = 1.015-1.122). When shift work and occupational noise exposure were combined, the PRs for hearing loss were highest among individuals with the longest shift work (≥10 years) and longest noise exposure (≥20 years) durations, whether for bilateral (PR = 1.114, 95%CI = 1.068-1.162) or any ear (PR = 1.065, 95%CI = 1.034-1.096). A short duration of shift work may be a risk factor for hearing loss in women and could increase the prevalence of hearing loss when combined with occupational noise.