WEDNESDAY, May 9 (HealthDay News) -- Older obese men with low
levels of testosterone can lose weight when levels of the male
hormone are restored to normal, a new study suggests.
But it might not be the testosterone itself. Rather, it could be
that men undergoing the hormone therapy feel better and stronger so
they exercise more and watch their diet, speculated experts not
involved with the study.
"It [the study's conclusion] is overly optimistic," said Dr. Bradley Anawalt, a spokesman for The Endocrine Society and chief of medicine at the University of Washington Medical Center in Seattle. "There is very little evidence that testosterone should cause weight loss in men obese or otherwise; it usually results in weight gain."
Anawalt, who was not involved in the study, noted the study was
sponsored by Bayer, which makes testosterone supplements.
"If you were a drug company, the best product in the world would be a drug that causes you to lose weight, increases muscle and strength and improves your sex drive," he said.
Testosterone shouldn't be looked at as a miracle weight-loss
drug, Anawalt said. "Before anybody got excited about this, there
[would] need to be lot more studies done to reproduce these
findings," he added.
The findings were to be presented Tuesday at the European
Congress on Obesity in Lyon, France.
The study was led by Dr. Farid Saad, from Bayer Pharma AG in
Berlin.
For the study, the researchers followed 251 obese men aged 38 to
83 with low testosterone levels. Among these men, 214 were followed
for two years and 115 were followed for five years.
The men were given 1,000 milligrams of testosterone by injection
when the study started, again at six weeks and then every 12 weeks
until the end of the trial.
The men who were followed for five years lost an average of 35
pounds. Their average body-mass index -- a measurement that takes
height and weight into account -- dropped from 34 to 29, moving
them from the obese category into the overweight category. In
addition, they also saw improvements in their cholesterol and
triglyceride levels, along with their blood pressure.
In addition, there was no increase in the risk of prostate
cancer, researchers noted.
"Raising serum testosterone to normal reduced body weight, waist circumference and blood pressure, and improved metabolic profiles. These improvements were progressive over the full five years of the study," the study authors said.
Obesity has been linked with reduced testosterone, according to
the researchers. Men older than 45 who have low testosterone levels
are about twice as likely to be obese, have type 2 diabetes and
have high blood pressure as men with normal testosterone levels,
they added.
There may be a number of reasons why, the study authors said.
Increased testosterone improves energy and motivation to do
physical activity; testosterone also increases lean body mass,
which increases the amount of energy used.
Another expert, Dr. Spyros Mezitis, an endocrinologist at Lenox
Hill Hospital in New York City, added that "anecdotally we have
been seeing improvement in elderly men with low testosterone taking
testosterone, including improved cholesterol, more lean body mass
and fat loss."
Mezitis agreed that the weight loss may have been a result of
feeling better and stronger, allowing the men to exercise more.
Because this study was presented at a medical meeting, the data
and conclusions should be viewed as preliminary until published in
a peer-reviewed journal.
More information
For more on obesity, visit the
U.S. National Library of Medicine.