Older men with low levels of testosterone may have an increased long-term risk of death compared to men with normal testosterone, according to a new study accepted for publication in the Journal of Clinical Endocrinology & Metabolism (JCEM).
"This is the first report linking low levels of testosterone with earlier death in relatively healthy older men,” said Gail Laughlin, Ph.D., assistant professor at the University of California San Diego. “These results do not suggest testosterone supplementation for all older men, because levels above average did not make a difference.”
This study involved 794 men, ages 50 to 91 years, who were living in a southern California community and who participated in the Rancho Bernardo Study in the 1980s. Men whose total testosterone levels at the beginning of the study were in the lowest quartile (<241 ng/dl) were 40 percent more likely to die over the next 18 hears than those with higher levels. This difference was not explained by age, illness, adiposity, or lifestyle.
“We want to emphasize that this is an observational study,” said Laughlin. “We cannot recommend that any man take testosterone based on these results. Only randomized clinical trials can determine whether testosterone supplements are safe and can promote longevity. In the meantime, lifestyle changes to prevent or decrease obesity may also extend longevity."
Approximately 30 percent of men 60 years and older are estimated to have low testosterone, which is often accompanied by symptoms such as low bone and muscle mass, increased fat mass, low energy, and impaired physical, sexual, and cognitive function.
A rapid release version of this paper has been published on-line and will appear in the December 2007 issue of JCEM, a publication of The Endocrine Society.