8 June 2011
No link between age and testosterone levels
by Kate Melville
A new study from Australia adds weight to earlier European research that found no correlation between men's ages and their testosterone levels. The University of Sydney researchers speculate that poor health is the most likely contributor to reduced libido and fatigue in older men. The findings, presented at the The Endocrine Society's 93rd Annual Meeting in Boston, may put the brakes on the increasing number of testosterone replacement therapies being prescribed in Western nations.
The Australian researchers recruited 325 men over the age of 40 (median age 60) who had self-reported excellent health and no symptom complaints. The researchers took blood samples from the men nine times over three months. Men who took medications that affect testosterone were excluded from the study.
The researchers found that while obesity caused a mild lowering of blood testosterone levels, age had no effect on testosterone level. "The modest decline in blood testosterone among older men, usually coupled with nonspecific symptoms, such as easy fatigue and low sexual desire, may be due to symptomatic disorders that accumulate during aging, including obesity and heart disease," lead researcher David Handelsman said. "It does not appear to be a hormone deficiency state."
Handelsman had originally expected age to have a negative effect on serum testosterone, so the findings were "a bit of a surprise." The message for patients and their doctors, he added, is "older men with low testosterone levels do not need testosterone therapy unless they have diseases of their pituitary or testes. Age, in itself, has no effect on testosterone level in healthy older men."
Source: The Endocrine Society