Abstract
Background
Testosterone replacement therapy (TRT) has been investigated in older men as a preventative treatment against Alzheimer's disease (AD) and dementia. However, previous studies have produced inconsistent results. The inconsistencies may have arisen from differences in study design, dosage, treatment duration, and/or target population selection.
Methods
We designed a double blind, randomized, cross-over, placebo-controlled study to assess the physiological and clinical consequences of TRT in 44 older men (aged 61 + 7.7 years) with subjective memory complaints (SMC) in Indonesia. Participants were randomized into 2 groups, one group received 50 mg of transdermal testosterone daily for 24 weeks, followed by a 4 week washout period, then 24 weeks of placebo treatment; the other group received the reverse treatment (i.e. placebo, washout, then testosterone). Blood biomarkers were evaluated every 4 weeks in the first treatment period and every 8 weeks in the cross-over period.
Results
Significant increases in total testosterone, free (calculated) testosterone, dihydrotestosterone, and a decrease in luteinising hormone (LH) levels were observed (p<0.001) following TRT. Although there were significant increases in red blood cell counts, hemoglobin and prostate specific antigen (PSA) levels following TRT, they remained within normal ranges; an increased risk of prostate cancer or atherosclerosis would only have been indicated by much higher changes. No significant differences in estradiol, sex hormone binding globulin (SHBG), insulin levels, body fat percentage, or BMI were detected.
Conclusions
This first hospital-based study on elderly Indonesian men with SMC provides valuable insight into the role of TRT in terms of safety and its potential to prevent AD.