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Research Links Low Testosterone, Higher Heart Risk in Men; But Doctors Urge More Study on Hormone Therapy

Posted on: Tuesday, 17 May 2005, 15:00 CDT

Low testosterone and other symptoms of so-called male menopause appear to increase a man's risk of developing heart disease, according to a provocative new study that is likely to fuel the debate over whether a large-scale clinical trial of the hormone is needed.

The finding, reported today in the Journal of the American College of Cardiology, comes as testosterone prescriptions and sales of related Internet anti-aging supplements are booming.

Studies have suggested that in older men, obese men and men with diabetes, low levels of testosterone were associated with heart disease, said senior author Olli Raitakari, a physician and researcher with Turku University Central Hospital in Finland.

"Our findings confirm in healthy, middle-aged men that normal testosterone levels are protective against atherosclerosis," Raitakari said. "It is possible that hormone replacement therapy may decrease the risk of cardiovascular diseases in men with low hormone levels."

Yet Raitakari, and others not connected with the study, pointed out that although the study found a strong association between atherosclerosis and so-called andropause and low testosterone, it was not proof.

What is needed is a clinical trial in which testosterone is given to men to see whether it actually prevents heart attacks and strokes, doctors said.

"It raises a lot of interesting questions," said Robert Dieter, an assistant professor of medicine at the Medical College of Wisconsin and a vascular medicine specialist at Froedtert Memorial Lutheran Hospital in Wauwatosa and Community Memorial Hospital in Menomonee Falls. "What this study didn't show is whether (testosterone) supplementation has any benefit."

Dieter said he is concerned about men taking over-the-counter supplements that claim to boost testosterone without seeing a doctor to determine whether they need the hormone.

Ads for such products can be found all over the Internet.

Another big concern with testosterone supplementation is that it might also increase the risk of prostate cancer, doctors said.

An editorial accompanying the study, however, noted that more men die or become ill because of heart disease than prostate cancer.

Prescriptions outpace science

The concerns come when prescriptions for testosterone are increasing. In 2002, more than 1.7 million prescriptions for testosterone were written, a 30% increase from 2002 and a 170% increase from 1999, according to a November 2003 report from the Institute of Medicine.

The institute noted that the rapidly growing use of testosterone among men seeking to counter the effects of aging had outpaced the scientific evidence about the benefits and risks to users.

With women's hormone replacement therapy, doctors noted, prescriptions also outpaced science, and years later, it was found that such treatments did not protect against cardiovascular disease and might even increase risk.

"People want a magic pill," said Nieca Goldberg, a spokeswoman for the American Heart Association and a cardiologist at Lenox Hill Hospital in New York. "I would be careful.

"Before we start prescribing it for heart disease, there clearly has to be a bigger trial."

Andropause in men occurs differently from menopause in women. It often takes place gradually over years, compared with a more rapid and extensive onset of symptoms in women after their ovaries stop functioning.

In men, a diagnosis often requires low levels of testosterone as well as symptoms such as loss of libido, depression and muscle weakness.

Yet it is difficult to diagnose andropause, and there is no clear- cut consensus on who needs to be treated, doctors said.

It is estimated that 5% to 10% of men older than 50 suffer from andropause and low testosterone, said David Toth, an endocrinologist and physician with Midwest Endocrinology Associates and St. Luke's Medical Center in Milwaukee.

Toth said he sees about 10 new patients with suspected low testosterone each month.

He said there is not unanimous agreement among doctors on what level of testosterone is considered low, at least in middle-aged men.

"We know what is normal for teenagers and people in their 20s," Toth said. "It is very hard to know what a normal level is as a population gets older."

Often, men will complain of depression, loss of sex drive, difficulty sleeping or increased fat mass. "But any 50- or 60-year- old guy is likely to have at least one, if not several, of those," Toth said.

An important question'

If testosterone therapy is needed, the hormone can be administered several ways, including weekly or monthly injections, a patch or a gel.

Gel or patch testosterone costs $90 to $180 a month and usually is covered by insurance, Toth said. Injections are less expensive but must be given by a medical professional.

Observational, laboratory and animal studies have produced conflicting findings about whether testosterone protects against cardiovascular disease, Toth said.

Because of that, Toth said he, too, would like to see a large- scale clinical trial.

"It is an important question to be answered," he said.

Study involved 239 men

To advance the issue, the Finnish researchers studied 239 men aged 40 to 70.

In that group, they found 99 men with an average age of 58 who were considered andropausal. The men had symptoms and low levels of testosterone or high levels of luteinizing hormone, a substance that indicates testosterone production is low.

The researchers then took ultrasound images of the carotid arteries of all the men in the study. Carotid ultrasound testing, which measures the thickness of the artery, is considered to be an excellent test for coronary artery disease.

The carotid arteries of the men who were andropausal were significantly thicker than the men who were not andropausal.

Obese men in the study also were more likely to be andropausal, possibly because testosterone can be converted to estrogen in fat cells.

The authors said a possible limitation of their study was the relatively small sample, but they said their findings were distinct, and that the sample size was not likely to detract from the validity of the study's main findings.

"A portion of men will develop andropausal hormone profile and symptoms with aging, and these men may also be at increased risk of developing heart disease," Raitakari said. "Controlled studies should be planned to test whether testosterone supplementation could help these men."

Copyright 2005, Journal Sentinel Inc. All rights reserved. (Note: This notice does not apply to those news items already copyrighted and received through wire services or other media.)

Source: Milwaukee Journal Sentinel

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