Secondhand smoke exposure and the risk of hearing loss.

Hearing loss has been associated with tobacco smoking, but its relationship with secondhand smoke is not known. We sought to investigate the association between secondhand smoke exposure and hearing loss in a nationally representative sample of adults. The National Health and Nutrition Examination Survey (NHANES), a nationally representative cross-sectional dataset, was utilised to investigate the association between secondhand smoke exposure and hearing loss. Data collected from non-smoking participants aged 20-69 years were included in the analysis if they had completed audiometric testing, had a valid serum continue value, and provided complete smoking, medical co-morbidity and noise exposure histories (N=3307). Hearing loss was assessed from averaged pure-tone thresholds over low- or mid-frequencies (500, 1000 and 2000 Hz) and high-frequencies (3000, 4000, 6000 and 8000 Hz), and was defined as mild or greater severity (pure-tone average in excess of 25 dB HL). Second-Hand Smoke (SHS) exposure was significantly associated with increased risk of hearing loss for low-/mid-frequencies (adjusted OR=1.14; 95% CI 1.02-1.28 for never smokers and 1.30; 1.10-1.54 for former smokers) and high-frequencies (1.40; 1.22-1.81 for former smokers), after controlling for potential confounders. Findings from the present analysis indicate that SHS exposure is associated with hearing loss in non-smoking adults.