Science Story

05 July 2009 02:36 BST

Low testosterone 'increases death risk'

Men with low levels of testosterone may have an increased risk of death over the age of 50, new research claims.

Scientists behind the study say it is the first to link deficiency of this sex hormone with increased death from all causes over time in relatively healthy men living in the community.

Study author Dr Gail Laughlin argued that the research "strongly suggests that the association between testosterone levels and death is not simply due to some acute illness".

Higher levels of testosterone were not linked with a decreased risk of mortality.

The results were presented yesterday at The Endocrine Society's annual meeting in Toronto.

Researchers studied all causes of death in nearly 800 men aged between 50 and 91 over an 18-year period from the 1970s onwards.

At the beginning of the 1980s, almost one-third of these men had suboptimal blood testosterone levels for men their age.

This group had a 33 per cent greater risk of death during the following years than men with higher testosterone levels.

The study ruled out other factors including smoking, drinking, physical activity level or pre-existing diseases (such as diabetes or heart disease) as contributing to this increased risk.

Men with low testosterone were more likely to have elevated markers of inflammation, which may contribute to diseases, and larger waist girth along with a number of cardiovascular and diabetes disease risk factors related to this type of fat build-up.

"It's very possible that lifestyle determines what level of testosterone a patient has - it may be possible to alter the testosterone level by lowering obesity," said principal investigator Dr Elizabeth Barrett-Connor.

"We are very excited about these findings, which have important implications, but we are not ready to say that men should go out and get testosterone to prolong their lives. We're not ready to take this to the prescribing pharmacist."