Background Age-associated cognitive decline may be influenced by testosterone status. However, studies evaluating the impact of bioavailable testosterone, the active, free testosterone, on cognitive function are scarce. Our study determined the relationship between calculated bioavailable testosterone and cognitive performance in older men. Methods We used data from the US National Health and Nutrition Examination Survey (NHANES) between 2013 and 2014. This study consisted of 208 men aged ≥ 60 years. Bioavailable serum testosterone was calculated based on the total serum testosterone, sex hormone-binding globulin, and albumin levels, while cognitive performance was assessed through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test (WLLT), Word List Recall Test (WLRT), and Intrusion Test (WLLT-IC and WLRT-IC), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Multiple linear regression analyses were performed upon adjustment for age, ethnicity, socio-economic status, education level, medical history, body mass index, energy, alcohol intake, physical activity levels and sleep duration. Results A significant positive association between bioavailable testosterone and DSST (β: 0.049, P=0.002) score was detected, with no signs of a plateau effect. No significant associations with CERAD WLLT (P=0.132), WLRT (P=0.643), WLLT-IC (P=0.979), and WLRT-IC (P=0.387), and AFT (P=0.057) were observed. Conclusion Calculated bioavailable testosterone presented a significant positive association with processing speed, sustained attention and working memory in older men above 60 years of age. Further research is warranted to elucidate the impact of the inevitable age-related decline in testosterone on cognitive function in older men.

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生物可利用血清睾酮与老年男性认知功能的关联：来自国家健康和营养检查调查的结果

背景 与年龄相关的认知能力下降可能受睾酮状态的影响。然而，评估生物可利用睾酮（活性游离睾酮）对认知功能影响的研究很少。我们的研究确定了计算出的生物可利用睾酮与老年男性认知能力之间的关系。方法 我们使用了 2013 年至 2014 年间美国国家健康与营养检查调查 (NHANES) 的数据。该研究包括 208 名年龄≥60 岁的男性。生物可利用的血清睾酮是根据总血清睾酮、性激素结合球蛋白和白蛋白水平计算的，而认知能力是通过建立阿尔茨海默氏病登记表联盟 (CERAD) 单词列表学习测试 (WLLT)、单词列表评估的召回测试（WLRT），和入侵测试（WLLT-IC 和 WLRT-IC）、动物流畅性测试（AFT）和数字符号替换测试（DSST）。在调整年龄、种族、社会经济地位、教育水平、病史、体重指数、能量、酒精摄入量、身体活动水平和睡眠时间后，进行多元线性回归分析。结果检测到生物可利用睾酮和 DSST 评分之间存在显着正相关（β：0.049，P=0.002），没有平台效应的迹象。未观察到与 CERAD WLLT (P=0.132)、WLRT (P=0.643)、WLLT-IC (P=0.979) 和 WLRT-IC (P=0.387) 和 AFT (P=0.057) 的显着关联。结论 计算出的生物可利用睾酮与 60 岁以上老年男性的处理速度、持续注意力和工作记忆呈显着正相关。