Levels of sex hormones have limited effect on cognition in older men with or without prostate cancer

Androgen deprivation therapy is commonly used to treat prostate cancer, but by lowering testosterone levels it may affect cognitive function. However, the relationship between testosterone and cognition remains unclear. We examined the relationship between sex hormones (total testosterone, bioavailable testosterone, and estradiol) and cognition in a cross-sectional study of 198 older men (mean age 69.2 years, median education 16 years) with and without prostate cancer, none of who had started androgen deprivation therapy. We found relationships between total testosterone and two of four measures of working memory. Similar relationships were found in regression analyses adjusted for age and education with both total testosterone and estradiol. Neither hormone was related to other cognitive domains, nor was bioavailable testosterone level. Although cognitive function was not generally related to sex hormone levels in older men, there may be a weak association with working memory. These results may help guide future studies.