Effects of transdermal testosterone on bone and muscle in older men with low bioavailable testosterone levels, low bone mass, and physical frailty.

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.