Relationship between Metabolic Syndrome and Hearing Loss: Korea National Health and Nutritional Survey

Background: We aimed to evaluate the association between metabolic syndrome (MetS) and hearing loss (HL) in light of noise exposure in Korean middle-aged adults. Methods: Subjects were 10,356 adults (4,509 males, 5,847 females) aged 40–80 years, who completed audiometric tests and laboratory examinations as part of the Korea National Health and Nutrition Examination Survey between 2010 and 2012. MetS was defined according to the National Cholesterol Education Program-Third Adult Treatment Panel (NCEP III) and International Diabetes Federation (IDF). Low-frequency HL was defined as pure tone averages >25 decibels (dB) at low frequencies (0.5, 1, and 2 kilohertz [kHz]). High-frequency HL was defined as pure tone averages >25 dB at high frequencies (3, 4, and 6 kHz). Odd ratios (OR) and 95% confidence intervals (CI) of MetS associated with each HL type were estimated using multiple logistic regression analysis after adjusting for covari-ates and taking into consideration sampling weight. Results: Thirty eight point one percent and 28.6% met the MetS by NCEP III and IDF criteria, respectively. Prevalence of HL was 29.3% and 63.9% for low- and high-frequency HL, respectively. MetS defined by NCEP III was associated with higher risk of high-frequency HL (OR, 1.35; 95% CI, 1.05–1.73), while MetS by IDF criteria was not. The interaction by the noise exposure on the MetS and high-frequency HL was not significant (P-interac-tion=0.100). There was no association between MetS and low-frequency HL, regardless of applied diagnostic criteria for MetS. Conclusion: Our findings suggest MetS is associated with high-frequency HL in people with exposure to noise.