Association between Fish Intake and Serum Testosterone Levels in Older Males: The Hitachi Health Study II

Fish are rich in omega-3 polyunsaturated fatty acids and vitamin D, which can promote testosterone synthesis and secretion. However, some contaminants present in fish may disrupt testosterone production. This study aimed to investigate the association between fish intake (total, fatty, and lean fish) and serum testosterone levels in older males. This cross-sectional study included 1545 Japanese males aged 60–69 y who participated in the baseline survey of the Hitachi Health Study II. Fish intake was estimated using a validated brief-type self-administered diet history questionnaire. Total testosterone levels were measured by chemiluminescence immunoassay. Multivariable linear regression analysis was used to analyze the association between fish intake and serum testosterone levels. Higher total fish intake was associated with higher levels of serum testosterone, with an adjusted mean [95% confidence interval (CI) of 5.63 (5.43, 5.83) and 5.99 (5.78, 6.20)] ng/mL for the 1st and 4th quartiles of total fish intake, respectively (P for trend = 0.06). When analyzing fatty and lean fish separately, higher intake of lean fish, but not fatty fish, was associated with higher levels of serum testosterone: adjusted mean (95% CI): 5.63 (5.43, 5.82) and 6.00 (5.79, 6.20) ng/mL for the 1st and 4th quartiles of lean fish intake, respectively (P for trend = 0.01). Among older males, higher intake of total fish, particularly lean fish, was associated with higher serum testosterone levels. Curr Dev Nutr 20xx;x:xx.