Newswise, February 19,
2016 – As men age, their testosterone levels decrease, but prior studies of the
effects of administering testosterone to older men have been inconclusive.
Now, a new study shows
testosterone treatment for men age 65 and older improves sexual function,
walking ability and mood, according to findings published in the New England
Journal of Medicine by a team of researchers from 12 medical centers, including
Cora E. Lewis, M.D., of the University of Alabama at Birmingham.
The Testosterone Trials,
or TTrials, are a coordinated group of seven trials, and researchers have
analyzed the results of the first three — sexual function, physical function
and vitality. They found that testosterone treatment increased the blood
testosterone level in the study subjects to the mid-normal range for younger
men.
Testosterone treatment
led to modest improvements in all aspects of sexual function, including sexual
activity, sexual desire and the ability to get an erection. It also resulted in
small improvements in indexes of mood and depression and some but not all
measures of physical function. Treatment did not improve overall energy level.
With 51,085 men screened
and 790 who qualified, the TTrials are now the largest trials to examine the
efficacy of testosterone treatment in men 65 and older whose testosterone
levels are low due seemingly to age alone.
Lewis, a professor in
the UAB Division of Preventive Medicine and co-author on the testosterone
study, says this new research fills a prominent gap in the evidence for the
possible benefits of testosterone in men in this age group, a gap identified by
a 2003 report from the Institute of Medicine. Additional evidence will come
from the studies in other trials on cognitive function, bone health,
cardiovascular disease and anemia.
“We now have some
evidence on the specific symptoms that seem to respond, or don’t respond, to
testosterone therapy in men 65 years old and over,” Lewis said. “However, there
are still big questions about overall benefits and risks. The negative effects of
testosterone treatment are still unclear.”
Across the three trials,
adverse events including heart attack, stroke and prostate problems were
similar in men who received testosterone and men who received placebo. So,
while the TTrials did not find harmful effects, Lewis says a larger and longer
clinical trial comparing testosterone therapy to placebo to definitively assess
the risks is needed.
Lewis says men
considering testosterone treatment should consult their doctor.
“Men should discuss
their symptoms and their health history with their doctor since testosterone
treatment seems to affect some symptoms and not others,” she said. “Men should
have their testosterone levels checked to be sure they have low testosterone.”
She also adds that it is
important to have levels checked in the morning since testosterone levels
naturally change over the course of a day.
The TTrials were
supported by a grant from the National Institute on Aging of the National
Institutes of Health and funding from other institutes of the NIH.