London, Oct 20 (IANS) Aggressive men with higher testosterone levels are less likely to die of heart disease, says a new study.

Medical scientists 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 Professor 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 to one in eight (12 percent) of those with normal levels, reports the Telegraph.

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, according to the journal Online First Heart.

Previous studies have shown that healthy men with low testosterone are more likely to die before those with normal levels.

This study, published Wednesday, shows a similar effect in those already diagnosed with heart disease.

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.

"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," Channer argued.