Medics who followed 930 men diagnosed with coronary heart disease found that those with low testosterone were almost twice as likely to die over a seven year period, than those with normal levels of the hormone.
The study, led by Prof Kevin Channer of Royal Hallamshire Hospital in Sheffield, adds weight to recent research overturning the widely-held belief that testosterone increases heart disease risk.
During the monitoring period one in five of those with low testosterone levels died, compared with one in eight (12 per cent) of those with normal levels.
Even having what the researchers described as “borderline” low levels of testosterone raised the risk of an early death, both from heart disease and other causes.
Previous studies have shown that healthy men with low testosterone are more likely to die before those with normal levels.
This study, published today (WED) in the journal Online First Heart, shows a similar effect in those already diagnosed with heart disease.
Prof Channer, a cardiologist, said testosterone was struggling to overcome an image problem caused by the mistaken belief that it caused health problems.
He said there were no studies that showed normal, physiological levels of the hormone were harmful.
The mistaken belief that it was harmful was based on studies of “testosterone abuse” among athletes, who had injected “industrial quantities” of it, giving themselves levels more than 100 times what the body produced.
Theirs was the fourth study showing testosterone’s protective properties at normal levels, he added.
Prescription of replacement testosterone for men with low levels, who also have Type 2 diabetes or heart disease, has risen markedly in recent years.
But he said there was now a pressing need for a large-scale trial to test the hypothesis that such male hormone replacement therapy saved lives.
“If it can be shown beyond reasonable doubt that mortality is reduced by replacement testosterone to physiological levels, then it should be given to all men with low levels,” he argued.
However, he said an application for trial funding from the Medical Research Council, which awards Government grants, had just been refused.
Pharmaceutical companies were reluctant to fund an expensive large-scale study into male HRT because female HRT had been tainted by findings that it increased cancer risk, he added.
However, he said female HRT had been administered poorly, with women often given far too high doses of oestrogen and progesterone.
“There’s a little bit of fear out there,” he said.
Ellen Mason, Senior Cardiac Nurse at the British Heart Foundation, said research in animals showed that replacing testosterone could reduce the furring of arteries.
However, she cautioned: “Although this research highlights a significant link between heart disease and testosterone deficiency, it is not clear if low testosterone is behind poorer survival in men with low levels of the hormone.”