Seafood and polyunsaturated fatty acid intake and age-related hearing loss: a cross-sectional study conducted in Japan

BACKGROUND: Age-related hearing loss (ARHL) is a common condition associated with dementia, social isolation, and reduced quality of life. N-3 polyunsaturated fatty acids (N-3 PUFAs), mainly derived from seafood, have been hypothesized to protect against ARHL through anti-inflammatory and antioxidant effects. However, evidence remains inconsistent. This cross-sectional study examined the association of seafood and dietary fatty acid intakes with ARHL in a Japanese population with high seafood consumption. METHODS: A total of 13,908 adults aged 50-79 years from the Tohoku Medical Megabank Project Cohort Study were included. Hearing thresholds were measured by pure-tone audiometry at 500, 1,000, 2,000, and 4,000 Hz. Dietary intake was assessed using a validated food frequency questionnaire. Seafood, N-3 PUFA, and saturated fatty acid (SFA) intakes were categorized into quartiles. Multivariable linear regression was used to estimate adjusted mean differences in hearing thresholds. RESULTS: In men, higher SFA intake was significantly associated with lower hearing thresholds at 1,000 Hz (Q4 vs. Q1: β = -2.23 dB HL, 95% CI: -3.437 to -1.023) and for pure-tone average (β = -1.704 dB HL; 95% CI, -2.872 to -0.536). Seafood and N-3 PUFA intakes were not significantly associated with hearing thresholds. In women, no significant associations were observed. CONCLUSION: In this population with high seafood consumption, seafood and N-3 PUFA intakes were not associated with hearing thresholds. Low SFA intake may be associated with higher hearing thresholds in Japanese men, suggesting that the relationship between dietary fatty acids and ARHL may be complex and may differ by sex.