Image: Behavioural changes are seen as a factor

New research presented at The Endocrine Society's 94th Annual Meeting in Houston, US, has found that a decline in men's testosterone levels over time is "not an inevitable part" of ageing.

Gary Wittert, professor of medicine at Australia's University of Adelaide, has co-authored the study and said the decline was "more likely" due to behavioural and health changes.

Obesity is among the factors believed to play a role in declining testosterone levels over time, following the research which involved more than 1,500 men.

The National Health and Medical Research Council of Australia supported the study, which analysed testosterone measurements from participants taken at two clinic visits five years apart.

After those showing abnormal lab values or who were taking medication were excluded, the results comprised data analysis from 1,382 men aged between 35- and 80-years-old.

On average, there was no significant decline over the five-year period but researchers uncovered certain factors linked to lower testosterone levels in the analysis of certain sub-groups.

Wittert said: "Men who had declines in testosterone were more likely to be those who became obese, had stopped smoking or were depressed at either clinic visit.

"It is critical that doctors understand that declining testosterone levels are not a natural part of ageing and that they are most likely due to health-related behaviours or health status itself."

The findings were presented by Andre Araujo, a visiting professor at the University of Adelaide and who is the vice president of epidemiology at New England Research Institutes, US.

Details: www.newswise.com

Details: www.endo-society.org (Endo 2012)

Image: Stefan Schurr/shutterstock.com