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Many men age 65 and up who have low levels of testosterone say their sense of well-being, not to mention their libido, isn't what it used to be. That's why some doctors prescribe testosterone replacement. In the past, studies haven't had clear results about how well replacement works and whether it's safe. Today, there are new findings from five studies, but they don't do much to clear up the confusion. NPR's Patti Neighmond reports.
PATTI NEIGHMOND, BYLINE: The studies, called the TTrials, were conducted at 12 medical centers across the country. Seven-hundred-eighty-eight men with low levels of testosterone took part. About half received testosterone gel. The other half got a placebo. Scientists looked at potential benefits of the hormone gel, including cognition, bone health, heart health and anemia. Researcher Susan Ellenberg says the bottom-line message for patients is mixed.
SUSAN ELLENBERG: It tells them that this is not likely to be a magic bullet for them but that it may lead to some improvements in some areas and probably not in others.
NEIGHMOND: The biggest improvement, she says, was bone health.
ELLENBERG: The volumetric bone density increased much more on testosterone than on placebo. It was a very strong effect in measuring both bone density and bone strength.
NEIGHMOND: Longer-term research is needed, she says, to make sure stronger bones mean fewer fractures as men age. There was some benefit for men with anemia - more on that study in a moment. But when it came to cognition and memory, there were no improvements among the men on testosterone gel. And there was a red flag when it came to plaque buildup in the arteries, a risk factor for heart disease.
ELLENBERG: The volume of plaque increased more on the testosterone arm than on the placebo arm. And that difference was statistically significant.
NEIGHMOND: Again, large long-term studies are needed to see whether testosterone supplements actually increase incidence of heart attack and stroke. A separate study also published today found no increase. The companies that manufacture the supplements are now planning more research. Endocrinologist Shalender Bhasin with Boston's Brigham and Women's Hospital says because there's not enough evidence that testosterone is safe for the cardiovascular system, doctors should be cautious with certain patients.
SHALENDER BHASIN: The frail elderly or people who have preexisting heart disease or have had a recent heart attack or a stroke - I think one should be particularly careful in those individuals.
NEIGHMOND: Decisions about whether to take or not take testosterone, he says, should be made after careful discussion between patients and their doctors.
BHASIN: Physicians should do what physicians always do. They weigh the available evidence and individualize their treatment decisions and have that conversation with their patients about the uncertainty, about the risks and benefits.
NEIGHMOND: Earlier research with this same group of men showed clear improvements in sexual function and libido along with a slight elevation in mood. Patti Neighmond, NPR News.
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