Older men treated with testosterone
run a higher risk of death, heart attacks and strokes, according to a study suggesting the hormone therapy may need to be reconsidered.
The researchers followed
more than 8 700 men who had low levels of the hormone, of whom 1 223 took a testosterone
supplement for a median period of around two years.
Three years later, nearly
one in five of the men who had not taken a supplement had suffered a heart
attack or stroke, or had died.
That figure jumped to one
in four among the group who had been treated with testosterone -- an overall
increased risk of nearly 30%.
The increased risk of
catastrophic events was especially notable, said researcher Anne Cappola of the
University of Pennsylvania, because "the men who were taking testosterone in
this study were slightly healthier to begin with."
The men receiving
testosterone also tended to be younger -- they had an average age of 61,
compared to an average age of 64 for the untreated men.
"These findings raise
concerns about the potential safety of testosterone therapy," the authors,
including lead researcher Rebecca Vigan of the University of Texas, wrote in
the study, published in the Journal of the American Medical Association.
They said further studies
were needed "to properly characterise the potential risks,"
especially among older men or men with other risk factors.
The number of annual
prescriptions for testosterone therapy in the US increased five-fold between 2000 and
2011, reaching 5.3 million prescriptions worth about $1.6b, the authors emphasised.
The therapy is recommended
for those with below-normal levels of the hormone whose symptoms include
diminished sex drive, low energy and failing memory.
Risk of death
In addition to improving
sex drive and bone density, the hormone has been shown to increase muscle mass
It is not clear from this
research whether the increased risk of death, heart attack and stroke existed
among patients prescribed testosterone therapy for "low T syndrome"
or younger men taking it for physical enhancement, Cappola said.
An ongoing trial
of more than 800 men over the age of 65 receiving testosterone or a placebo
could help provide guidance for older men considering testosterone therapy, the study concluded.
Until more is known,
however, "prescribers and patients should be wary," she said.