Testosterone and cognitive function in ageing men: data from the Florey Adelaide Male Ageing Study (FAMAS)

Recent evidence suggests that declining testosterone levels in ageing males may be associated with both normal and pathological cognitive ageing. The aim of the present analyses was to investigate whether endogenous gonadal steroid levels in males mediate or moderate the associations between age and performance on neuropsychological measures of verbal memory, executive function, and processing speed.

A cross-sectional analysis of the baseline data from 1046 community-dwelling men aged 35-80 years participating in the Florey Adelaide Male Ageing Study (FAMAS). Multiply adjusted analyses included participants' history of medical conditions, anthropometric measurements, medication use, smoking status, alcohol use and mood. Hormone measurements included total testosterone (TT), bioavailable testosterone (BT), calculated free testosterone (cEFT), oestradiol (E2), sex hormone binding globulin (SHBG), follicle stimulating hormone (FSH), and lutenising hormone (LH). Neuropsychological tests included the Fuld Object Memory Evaluation (FOME), Trails A and Trails B.

In multiply adjusted analyses, higher cEFT and TT levels were associated with both poorer verbal memory and executive function performance and faster processing speed. cEFT levels were found to moderate the relationship between age and verbal memory performance quadratically and to mediate the relationship between age and processing speed.

The results from this study suggest that higher levels of endogenous testosterone, particularly in the elderly, may have deleterious effects on cognitive functioning in men.