Deficiency in vitamin D is associated with bilateral hearing impairment and bilateral sensorineural hearing loss in older adults

Hearing impairment and vitamin D (VD) deficiency are both public health concerns. The purpose of the study was to examine whether VD deficiency and hearing impairment, specifically sensorineural hearing loss, are associated. Data from the National Health and Nutrition Examination Surveys (2001-2006, 2009-2012) were used in this cross-sectional study. The pure-tone average (PTA) was calculated for each ear at low speech frequencies of 0.5 to 4.0 kHz (LPTA) and higher frequencies of 3.0 to 8.0 kHz (HPTA). Hearing impairment was defined as >25 dB (LPTA/HPTA) and was further divided to "unilateral" and "bilateral." A subsample of 2010 participants with normal tympanometry and otoscopic examinations was analyzed to determine sensorineural hearing loss. Multivariable weighted multinomial regressions were used to estimate the adjusted odds ratios (ORs) and 95% CIs. Overall, 3489 participants aged 50 years or older with mean age (mean ± SD) 61.5 ± 9.1 years were included in the final study sample, of those, 924 (21.8%) had VD deficiency (<20 ng/mL). Hearing impairment (bilateral and unilateral) was detected at 1648 (40.5%) participants at LPTA and 2589 (70.5%) participants at HPTA. In the multivariable models, VD deficiency was significantly associated with bilateral hearing impairment at the LPTA (OR, 1.45; 95% CI, 1.12-1.89) and with bilateral sensorineural hearing loss at the LPTA (OR, 1.60; 95% CI, 1.13-2.26) but such association was not observed at the HPTA (unilateral, P value = .274; bilateral, P value = .423). In conclusion, VD may have a significant role in the human auditory system, where its deficiency might affect both ears in particular the inner ears where the sensorineural hearing loss occurs.