Exogenous testosterone (T) alone or with finasteride increases physical performance, grip strength, and lean body mass in older men with low serum T
Date
2005-03Author
Anawalt, Bradley D.
Tenover, J. Lisa
Bowman, F. DuBois
Bremner, William J.
Matsumoto, Alvin M.
Page, Stephanie T.
Amory, John K.
Metadata
Show full item recordAbstract
Testosterone (T) therapy in older men with low serum T levels increases
lean body mass and decreases fat mass. These changes might improve
physical performance and strength; however, it has not been established
whether T therapy improves functional outcome in older men. Moreover,
concerns exist about the impact of T therapy on the prostate in older men.
The administration of finasteride (F), which partially blocks the
conversion of T to the more potent androgen, dihydrotestosterone,
attenuates the impact of T replacement on prostate size and
prostate-specific antigen. We hypothesized that T replacement in older,
hypogonadal men would improve physical function and that the addition of F
to this regimen would continue to provide the T-induced improvements in
physical performance, strength, and body composition. Seventy men with low
serum T (<350 ng/dl), age 65 yr and older, were randomly assigned to
receive one of three regimens for 36 months: 1) T enanthate, 200 mg im
every 2 wk, with placebo pills daily (T-only); 2) T enanthate, 200 mg
every 2 wk, with 5 mg F daily (T + F); or 3) placebo injections and pills
(placebo). We obtained serial measurements of timed physical performance,
grip strength, lower extremity strength, body composition (by dual-energy
x-ray absorptiometry), fasting cholesterol profiles, and hormones. Fifty
men completed the 36-month protocol. After 36 months, T therapy
significantly improved performance in a timed functional test when
compared with baseline and placebo [4.3 +/- 1.6% (mean +/- sem, T-only)
and 3.8 +/- 1.0% (T + F) vs. -5.6 +/- 1.9% for placebo (P < 0.002 for both
T and T + F vs. placebo)] and increased handgrip strength compared with
baseline and placebo (P < 0.05). T therapy increased lean body mass [3.77
+/- 0.55 kg (T-only) and 3.64 +/- 0.56 kg (T + F) vs. -0.21 +/- 0.55 kg
for placebo (P < 0.0001)], decreased fat mass, and significantly decreased
total cholesterol, low-density lipoprotein, and leptin, without affecting
high-density lipoprotein, adiponectin, or fasting insulin levels. These
results demonstrate that T therapy in older men with low serum T improves
physical performance and strength over 36 months, when administered alone
or when combined with F, and suggest that high serum levels of
dihydrotestosterone are not essential for these beneficial effects of T in
men.