Effects of testosterone administration on cognitive function in hysterectomized women with low testosterone levels: a dose-response randomized trial.

PURPOSE: To determine the dose-dependent effects of testosterone administration on cognition in women with low testosterone levels. METHODS: 71 hysterectomized women with or without oophorectomy with total testosterone <31 ng/dl and/or free testosterone <3.5 pg/ml received a standardized transdermal estradiol regimen during the 12-week run-in period and were then randomized to receive weekly intramuscular injections of placebo, 3, 6.25, 12.5, or 25 mg testosterone enanthate for 24 weeks. Total testosterone was measured in serum by LC-MS/MS, and free testosterone levels were measured by equilibrium dialysis. Cognitive function was evaluated using a comprehensive battery of standardized neuropsychological tests at baseline and 24 weeks. RESULTS: 46 women who had baseline and end-of-treatment cognitive function data constituted the analytic sample. The five groups were similar at baseline. Mean on-treatment nadir total testosterone concentrations were 15, 89, 98, 134, and 234 ng/dl in the placebo, 3, 6.25, 12.5, and 25 mg groups, respectively. No significant changes in spatial ability, verbal fluency, verbal memory, or executive function were observed in any treatment arm compared to placebo even after adjustment for baseline cognitive function, age, and education. Multiple regression analysis did not show any significant relation between changes in testosterone concentrations and change in cognitive function scores. CONCLUSION: Short-term testosterone administration over a wide range of doses for 24 weeks in women with low testosterone levels was neither associated with improvements nor worsening of cognitive function.