Older men with higher or
lower testosterone levels are more likely to die early than those with
mid-range levels of the male sex hormone, a new study suggests.
It was already known that
low testosterone levels were associated with health problems, but this study
suggests that high levels of the hormone are also a problem.
Researchers measured the
testosterone levels of nearly 3 700 Australian men, aged 70 to 89, between 2001
and 2004. They then checked to see how many were still alive in December 2010.
Those with the lowest testosterone levels had the highest death rate, followed
by those with the highest levels.
Mid-range levels best
Men with mid-range levels
of testosterone had the highest survival rate, according to the study, which
was published in the Journal of Clinical Endocrinology &
"When the body
metabolises testosterone, it produces dihydrotestosterone (DHT), which is tied
to a lower risk of dying from ischemic heart disease," study author Bu
Beng Yeap, of the University of Western Australia, said in a journal news
release. In ischemic heart disease, there is reduced blood supply to the heart.
"Having the right
amount of testosterone and higher levels of DHT might indicate that these men
are in better health overall, or it could help them maintain good health as
they grow older," he said.
Sex hormones important
Although the study found an
association between high or low testosterone levels and increased death rates
in men, it did not establish a cause-and-effect relationship.
"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," Yeap said.
He said additional research
could help find ways to use this information to improve the health of older men.
The US National Library of
Medicine has more about testosterone.