Association of central obesity with the severity and audiometric configurations of age-related hearing impairment.

To investigate the effect of central obesity on the severity and characteristics of age-related hearing impairment (ARHI), we recruited 690 adult subjects with normal or symmetrical sensorineural hearing loss (SNHL). The effects of age, gender, morphometry, habits, systemic diseases, and environmental noise exposure on average pure tone hearing level at low frequencies (pure tone audiometry (PTA)-low) and high frequencies (PTA-high) were analyzed. After adjusting for age, gender, systemic disease, and other variables, waist circumference (WC) showed a significant positive association with PTA-low and PTA-high. In females, PTA-low and PTA-high only showed significant positive association with age, but not with WC or other variables. However, PTA-high showed a positive association with borderline significance with WC in female subjects older than 55. In males, WC as well as age and noise exposure showed significant positive associations with both PTA-low and PTA-high, primarily in subjects younger than 55. When both WC and BMI were taken into account in a backward stepwise multivariate linear regression analysis, WC, but not BMI, showed a significant positive association with PTA-low and PTA-high in males younger than 55, and with PTA-high with borderline significance in females older than 55. However, the audiogram patterns were not significantly affected by central obesity in either age or gender. Our results suggest that WC was, even after adjustment for BMI, an independent risk factor of ARHI, particularly for low and high frequencies in males younger than 55 and for high frequencies in female subjects older than 55.