Burkhardt Melanie S, Foster Jonathan K, Clarnette Roger M, Chubb S A Paul, Bruce David G, Drummond Peter D, Martins Ralph N, Yeap Bu B
School of Psychology, Murdoch University, Murdoch, Western Australia 6150, Australia.
J Clin Endocrinol Metab. 2006 Mar;91(3):1168-72. doi: 10.1210/jc.2005-1072. Epub 2005 Dec 20.
Reduced testosterone levels have been implicated as a potential causative factor in cognitive decline with older age. Men who possess the apolipoprotein E (APOE) epsilon4 allele have an increased risk of developing Alzheimer's disease; however, no studies have examined whether the influence of testosterone on cognition in healthy older men may be modulated by this genetic predisposition.
The objective of the study was to investigate the association between serum testosterone concentrations and cognitive performance in healthy older men, taking into account APOE epsilon4 status.
This was a cross-sectional study conducted from 2003 to 2004.
The study population consisted of community-dwelling males residing in Perth, Western Australia.
Healthy men over 55 yr, free of cognitive impairment and dementia (n = 45), were included in the study.
Participants had fasting early morning blood samples for testosterone and SHBG and were assessed for mood as well as indices of general cognition, verbal and visual memory, executive functioning, working memory, and attention.
There was a significant interaction between calculated free testosterone (FT) and APOE epsilon4 on general cognition (P = 0.01) and executive functioning, working memory, and attention (P < 0.01). Higher levels of FT were associated with better general cognition in non-epsilon4 carriers (P = 0.01). By contrast, in epsilon4 carriers higher FT levels were associated with lower scores on tests of executive functioning, working memory, and attention (P = 0.02). In men at increased risk for Alzheimer's disease, higher testosterone levels were not associated with better cognitive function.
Cross-sectional and prospective studies of testosterone and cognition in older men should take into account APOE epsilon4 status.
睾酮水平降低被认为是导致老年人认知能力下降的一个潜在因素。携带载脂蛋白E（APOE）ε4等位基因的男性患阿尔茨海默病的风险增加；然而，尚无研究探讨睾酮对健康老年男性认知的影响是否会受到这种遗传易感性的调节。
本研究的目的是在考虑APOE ε4状态的情况下，调查健康老年男性血清睾酮浓度与认知表现之间的关联。
这是一项于2003年至2004年进行的横断面研究。
研究人群包括居住在西澳大利亚珀斯的社区男性。
年龄超过55岁、无认知障碍和痴呆的健康男性（n = 45）被纳入研究。
参与者清晨空腹采集血样检测睾酮和性激素结合球蛋白，并评估情绪以及一般认知、言语和视觉记忆、执行功能、工作记忆和注意力等指标。
计算得出的游离睾酮（FT）与APOE ε4在一般认知（P = 0.01）以及执行功能、工作记忆和注意力方面（P < 0.01）存在显著交互作用。在非ε4携带者中，较高的FT水平与较好的一般认知相关（P = 0.01）。相比之下，在ε4携带者中，较高的FT水平与执行功能、工作记忆和注意力测试得分较低相关（P = 0.02）。在患阿尔茨海默病风险增加的男性中，较高的睾酮水平与较好的认知功能无关。
关于老年男性睾酮与认知的横断面和前瞻性研究应考虑APOE ε4状态。
