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.

WEDNESDAY, Nov. 30 (HealthDay News) -- Not all clogged arteries are created equal, with women and men facing different heart risks even when they have the same amount of coronary plaque, a new study suggests.

Analyzing the results of coronary CT angiographies -- non-invasive tests that look for coronary artery blockages -- in 480 patients with acute chest pain, scientists from the Medical University of South Carolina found that the risk of major cardiac events was significantly higher in women when they had a large amount of plaque buildup and extensive hardening of the arteries.

On the other hand, men faced greater risks of heart attack or coronary bypass surgery when their arteries contained "non-calcified plaque," fatty deposits that accumulate deep in artery walls.

While the study didn't specifically quantify the risks of each scenario for men and women, it may be valuable to physicians ordering tests for heart patients in distress, said study author Dr. John Nance Jr., a radiology resident at Johns Hopkins Hospital in Baltimore.

"This is so intriguing because now we're really starting to figure out the gender differences in heart disease," said Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City. She was not involved in the study.

"We've known in the past that women tend to deposit plaque differently . . . this nuance is something that's relatively new in how we risk-stratify patients," she added. "What it tells us is when we risk-stratify patients, it becomes more important to actually visualize plaque through CTA [angiography] or catheterization."

The study was slated to be presented Wednesday at a meeting of the Radiological Society of North America, in Chicago. Research presented at scientific meetings is preliminary and has not yet been peer-reviewed.

Study participants, two-thirds of whom were women, were an average age of 55. Using the coronary CT angiographies, researchers were able to determine the number of blood vessel segments with plaque, the severity of the blockage and the composition of the plaque.

By comparing those results with data accumulated over a nearly 13-month follow-up period, the researchers were able to link these factors with the incidence of major cardiac events. The analysis tested all types of coronary plaques -- non-calcified, calcified and mixed -- along with each individual type separately.

In the follow-up period, 70 patients suffered major cardiac events, including death, heart attack, unstable angina or bypass surgery.

"We're not sure why the risk differences exist [between the sexes] but women have smaller blood vessels and men have larger," said Dr. Jennifer Mieres, a cardiologist with the North Shore-LIJ Health System in Manhasset, N.Y. "We also believe that atherosclerosis (artery hardening) differs in how it's deposited in men and women."

Using this information will help doctors tailor treatments to each gender and customize their care, the health experts agreed.

"I think this is the sort of stuff we're going to start seeing more and more of," Nance said. "There are people out there who are anti-customized care and just don't think that's what we should really strive for, but this data kind of argues for that."

More information

The U.S. National Library of Medicine has more about atherosclerosis.