L-shaped relationship between dietary niacin intake and hearing loss in United States adults: National health and nutrition examination survey.

Hearing loss poses a significant threat to human health, with its prevalence increasing annually. Niacin (vitamin B3) is an essential B vitamin that plays a crucial role in energy metabolism and cellular repair in the body. Additionally, it exerts a protective influence on the cells of the inner ear. A correlation between dietary niacin and hearing loss has been reported; however, the results remain controversial, requiring further investigation. This study aimed to examine the potential association between dietary niacin intake and hearing loss in United States (U.S.) adults, providing a reference for dietary preventive management of hearing loss. In this cross-sectional study, data derived from the National Health and Nutrition Survey for U.S. adults aged 20 to 69 years, spanning the 2011-2012 and 2015-2016 cycles, were used. Logistic regression, restricted cubic spline models, subgroup analyses, and sensitivity analyses were used to assess the stability of the results. A total of 7675 participants were included, of whom 772 (10.1%) exhibited low-frequency hearing loss (LFHL), 1165 (15.2%) had speech-frequency hearing loss (SFHL), and 2816 (36.7%) had high-frequency hearing loss (HFHL). In the final model, the adjusted odds ratios of dietary niacin intake and LFHL, SFHL, and HFHL in Q2 (16.97-23.40 mg/day) were compared with those in Q1 (≤16.96 mg/day) and were 0.73 (0.57-0.92), 0.76 (0.61-0.94), and 0.80 (0.67-0.96), respectively. The relationship between dietary niacin intake and hearing loss (HL) was illustrated via an L-shaped curve in the restricted cubic spline with an inflection point of approximately 23.26 mg/day. The odds ratios for HL in individuals with niacin intake less than 23.26 mg/day were as follows: 0.950 (0.917-0.984) for LFHL, 0.951 (0.921-0.982) for SFHL, and 0.965 (0.939-0.992) for HFHL. To summarize, an "L"-shaped correlation between dietary niacin intake and the occurrence of HL in U.S. adults with an inflection point estimated at approximately 23.26 mg/day was revealed in the present study.