Testosterone therapy may not be as bad for men's heart health as
previously thought, but it doesn't seem to turn back time on their
sex lives either, a new trial shows.
"That was the surprising thing," said senior study author Dr.
Shalender Bhasin, director of the Boston Claude D. Pepper Older
Americans Independence Center at Brigham and Women's Hospital in
Boston. "Many middle-aged and older men take testosterone because
they feel it will improve their sex life, but the study showed that
men who had low-normal or slightly low levels did not show any
improvement."
Testosterone therapy has become big business in the United States,
as baby boomers seek ways to counter the effects of aging, Bhasin
said.
Sales of testosterone amounted to around $20 million a year in the
early 1990s, but by 2012 it had grown into a $2 billion industry, he
said.
However, recent studies have cast a pall on testosterone therapy,
indicating it may increase risk of heart attacks and strokes, said
Bhasin, who also serves as director of the hospital's Research
Program in Men's Health: Aging and Metabolism.
The U.S. Food and Drug Administration in March started requiring all
prescription testosterone products to carry a label warning about
possible increased risk of heart attacks and strokes.
"Testosterone has become a blockbuster drug," he said. "It's just
extraordinary growth, and there's been growing concern among the
regulatory agencies about the potential for the increase in risk of
cardiac events."
To assess the safety and effectiveness of testosterone treatment,
Bhasin and his colleagues enrolled 308 men older than 60 with
testosterone levels in the low or low-normal range, or about what
you'd expect in normally aging males.
As men age, their testosterone levels naturally decline, on average
by 1 percent a year after age 40, researchers said. Testosterone, a
hormone primarily secreted by the testicles, plays a key role in
male reproduction, muscle growth, bone mass and body hair.
About half the men were provided daily testosterone gel packets,
which they rubbed into their skin. The other men were given a
placebo gel that contained no medicine. The research was supported
by drug manufacturers Solvay Pharmaceuticals Inc. and Abbvie
Pharmaceuticals, which provided the testosterone gel.
After three years, researchers found that men using testosterone gel
had not suffered any additional hardening of their arteries,
compared with men using a placebo gel. Researchers used hardening of
the arteries as a measure because it is one of the leading causes of
heart attacks and strokes, Bhasin said.
However, the men also hadn't shown any improvement in their sex
lives, researchers said. Their levels of sexual desire, erectile
function and overall sexual function were about the same as men
taking the placebo. Their health-related quality of life also did
not differ significantly, the investigators found.
"The study shows that indiscriminate use of testosterone by older
men, whose levels are low-normal, is not indicated," Bhasin said.
"If your levels are low-normal, it's not going to help your sexual
function or quality of life."
The findings were reported in the Aug. 11 issue of the Journal of
the American Medical Association.
The study results call into question the whole purpose of
testosterone therapy, said Dr. Andrew Freeman, director of clinical
cardiology at National Jewish Health in Denver and a member of the
American College of Cardiology's Patient-Centered Care Committee.
"You have to ask yourself, why go on this drug if it doesn't make
anyone feel better?" Freeman said.
At the same time, other studies have shown that a healthy diet and
regular exercise can improve the sexual ability of aging men, he
added.
"The magic bullet may be lifestyle, not testosterone," Freeman said.
"Maybe we're looking in the wrong area. You can markedly improve
sexual function with diet and exercise, although many people don't
want to do that."
Bhasin pointed out that his clinical trial only looked at hardening
of the arteries, and was not lengthy enough to assess overall risk
of heart attack or stroke. There may be increased cardiac risk that
the trial could not detect, he said.
"We really need long-term trials to look at the effect of
testosterone on heart attacks or strokes," he said.