Low sex hormone 'increases depression'

Low testosterone puts older men at significant risk of depression, according to an Australian study which recommends those with abnormal levels consider getting injections of the sex hormone.

A study of almost 4000 elderly men has drawn the strongest link ever between low testosterone and mood.

Researchers at the University of Western Australia tracked levels of both in men aged 70-plus and found those with the lowest testosterone were three times more likely to suffer depression than those with the highest levels.

This was true irrespective of a man's physical health, a finding researchers say is important because bad health is known to increase the risk of depression and decrease hormone levels.

"Even when you take this into account, the association between low testosterone and depression is still strong," said Professor Osvaldo Almeida, lead author of the paper published in the US journal Archives of General Psychiatry.

"This is the most compelling case we have for the link yet."

Professor Almeida said the science behind the link was not yet fully understood.

But it might be that low hormones somehow trigger changes in the levels of neurotransmitters or hormones in the brain.

He said the evidence was now strong enough to support testosterone replacement therapy in depressed older men.

But only the 20% of men over 70 who have abnormally low testosterone, so-called hypogonadism, will likely benefit.

"We propose clinicians check their depressed older patients for hypogonadism, and if they have it then I think there is good rationale for considering using testosterone replacement to improve mood," Professsor Almeida said.

"This would be a totally new way of dealing with these men because currently they get nothing."

He said the benefits of giving hormone replacement needed to be proven in a randomised controlled trial before the therapy should be offered at a subsidised rate.

Testosterone replacement is most infamous for illegally boosting athletic performance, but an increasing number of older men are accessing the controversial treatment to build muscle mass and treat bone loss through osteoporosis.