Older men with midrange testosterone levels tend to live longer compared with men who have low or high levels, Australian researchers say.
Physicians have long known that low testosterone levels can signal health problems, but the new study, published online in the Journal of Clinical Endocrinology & Metabolism (Nov. 20, 2013), found men may not fare better when levels of the hormone rise too high.
“Older men who had testosterone in the middle range survived longer than their counterparts who had either low or high levels of the hormone,” said lead author Bu Beng Yeap, MBBS, PhD, of the University of Western Australia, Perth. “When the body metabolizes testosterone, it produces dihydrotestosterone (DHT), which is tied to a lower risk of dying from ischemic heart disease. Having the right amount of testosterone and higher levels of DHT might indicate these men are in better health overall, or it could help them maintain good health as they grow older.”
The population-based cohort study analyzed the mortality rate in a group of 3,690 community-dwelling men between the ages of 70 to 89 years in Perth. Participants’ testosterone and DHT levels were measured between 2001 and 2004. The authors analyzed the group’s survival rate as of December 2010.
Dr. Yeap and his co-authors divided the men into four groups based on their testosterone levels. Men with the lowest testosterone levels had the highest cumulative mortality rate, followed by the men with the highest testosterone levels. Men with circulating testosterone levels in the 9.8 nmol/L to 15.8 nmol/L range tended to live longer.
“Sex hormones are an important predictor of mortality in older men, but we haven’t determined if treatments to change testosterone and DHT levels can alter these outcomes. Additional research into these findings, including randomized clinical trials, could help identify ways to leverage this information to improve health in older men,” Dr. Yeap said.
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