Effects of Transdermal Testosterone on Bone and Muscle in Older Men with Low Bioavailable Testosterone Levels, Low Bone Mass, and Physical Frailty

Abstract

OBJECTIVES: To investigate the effects of testosterone supplementation on bone, body composition, muscle, physical function, and safety in older men. DESIGN: Double‐blind, randomized, placebo‐controlled trial. SETTING: A major medical institution. PARTICIPANTS: One hundred thirty‐one men (mean age 77.1 ± 7.6) with low testosterone, history of fracture, or bone mineral density (BMD) T‐score less than −2.0 and frailty. INTERVENTION: Participants received 5 mg/d of testosterone or placebo for 12 to 24 months; all received calcium (1500 mg/d diet and supplement) and cholecalciferol (1,000 IU/d). MEASUREMENTS: BMD of hip, lumbar spine, and mid‐radius; body composition; sex hormones, calcium‐regulating hormones; bone turnover markers; strength; physical performance; and safety parameters. RESULTS: Ninety‐nine men (75.6%) completed 12 months, and 62 (47.3%) completed end therapy (mean 23 months; range 16–24 months for 62 who completed therapy). Study adherence was 54%, with 40% of subjects maintaining 70% or greater adherence. Testosterone and bioavailable testosterone levels at 12 months were 583 ng/dL and 157 ng/dL, respectively, in the treatment group. BMD on testosterone increased 1.4% at the femoral neck and 3.2% at the lumbar spine (P=.005) and decreased 1.3% at the mid‐radius (P<.001). There was an increase in lean mass and a decrease in fat mass in the testosterone group but no differences in strength or physical performance. There were no differences in safety parameters. CONCLUSION: Older, frail men receiving testosterone replacement increased testosterone levels and had favorable changes in body composition, modest changes in axial BMD, and no substantial changes in physical function.