Should You Be Taking Testosterone?
Men getting on in years face at least two unpleasant facts: extra girth around their middles and decreasing testosterone levels. Most are well aware of the health risks of a spare tire. Now, new research presented today at a meeting of the Endocrine Society shows that low testosterone levels put men at a 33 percent higher risk of dying—from any cause—than their peers with levels in the normal range.
Does this mean men should consider testosterone supplements? They've enjoyed explosive growth since the early 1990s. But Gail Laughlin, assistant professor of family and preventive medicine at the University of California-San Diego and lead author, isn't so sure. Keeping that spare tire on board, she says, may have something to do with it—and that's within your control.
What do we know about low testosterone and the health problems associated with it ?
Older men who have a deficiency tend to have lower libido, less energy, a diminished ability to concentrate, and lower bone-mineral density. They also tend to accumulate fat around the middle, and are at increased risk of insulin resistance, metabolic syndrome, and diabetes.
In our study, men with low testosterone were 33 percent more likely to die than men with normal levels, even after we adjusted for smoking, alcohol, exercise, age, and body size. One thing that's important is that the mean age at baseline was 71, so this is an older population.
And were you surprised by the results?
Surprised? Well, we didn't have any expectation. Low levels of testosterone are associated with the development of a number of diseases in men who don't already have those diseases. Among them are insulin resistance, diabetes, and metabolic syndrome. And men who have coronary heart disease also have lower levels of testosterone, so we knew that testosterone levels were associated with disease; and whether that would translate into an association with survival, we weren't sure.
Does this mean that higher-than-normal testosterone levels would translate into longer survival?
That's a very important point. We did not find any evidence that having higher levels of testosterone was protective. In other words, in men whose testosterone values were above the average for this population, it didn't matter where they were in that range—they had the same risk of death.
It seems men with low testosterone are increasingly giving testosterone supplements a try. Does your research support getting extra testosterone?
We are not suggesting in any way whatsoever that men should go out and start taking testosterone—not even men with low levels of testosterone. We don't definitively know that it's beneficial and safe. We're gathering information, but what's been lacking—and what's still lacking—is any randomized controlled trial that is large enough with enough power to draw meaningful conclusions.
Do you have any advice for men who might be wondering what they can do?
Losing extra fat around the middle might be associated with an increase in testosterone. Central adiposity is associated with lower levels of testosterone, and it's been shown that men with central adiposity who are put on a weight-loss regimen have an increase in testosterone levels. We don't know why. It's really interesting because men tend to have lower levels of testosterone if they have more accumulation of fat around the middle, but women with a fat accumulation tend to have higher testosterone.
But you believe that men with low testosterone who have central adiposity have some control over their level of testosterone?
They may, yes indeed. It may be that if they institute lifestyle changes—the ones we're all struggling to do, including increased exercise and better eating-and lose some of that central adiposity. There are many systems in their body that will be improved by that, and testosterone levels are just one of them.
Twenty-nine percent of the men you studied had low testosterone. By this finding, it would seem that above age 50, diminishing testosterone seems to be fairly common.
That's correct. It declines gradually with aging in general, and many experts believe that above the age of 60, about 30 percent of men have testosterone deficiency. Symptoms include low energy, fatigue, inability to concentrate, low libido. There's a tremendous amount of research going on in this area right now. And what we need, of course, is a large placebo-controlled clinical trial to test supplements.
Is there one going on at UCSD?
It's in the development stages. It's multisite study that the National Institutes of Healthis reviewing for sponsorship. The principal investigator would be Peter Snyder at the University of Pennsylvania, and Elizabeth Barrett-Connor would be the lead at UCSD.