Smoking history and the rate of hearing decline in aging: Results from a longitudinal cohort study.

Hearing loss is a common and impactful condition among aging adults. Improved understanding of modifiable risk factors for hearing loss, including smoking, could promote hearing loss prevention. The purpose of this longitudinal study was to determine the association of smoking with the rate of age-related hearing decline across the frequency range. Participants were from the Medical University of South Carolina Longitudinal Cohort Study of Age-related Hearing Loss. Smoking pack years were calculated (at baseline) as the number of self-reported packs smoked per day multiplied by years smoked, and categorized as 0, >0 to 5, >5 to 15, and >15 pack years. Outcome measures were individual audiometric thresholds (0.25 to 8.0 kHz) and pure-tone average (PTA) of thresholds at frequencies 0.5 to -4.0 kHz, averaged bilaterally. We used linear mixed regression models to determine the association of pack years with the rate of annual threshold change at each frequency and PTA. This study included 1032 participants (mean age: 63.3 [SD 14.1] years, mean follow-up time: 5.4 [SD 6.0] years; 60.4 % female; 21.7 % Black race). Compared to non-smokers (0 pack years), participants with >15 pack years had poorer baseline thresholds at frequencies 2.0 to 8.0 kHz and PTA. Compared to non-smokers, participants with >5 to 15 and >15 pack years had higher rates of annual threshold change at frequencies ranging from 1.0 to 8.0 kHz and PTA. Findings corroborate smoking as a possible modifiable risk factor for hearing loss that could have lasting impacts on hearing.