Washington, Mar 4 : A new study has shown that older men with lower free testosterone levels in their blood appear to have higher prevalence of depression.
For the study, Osvaldo P. Almeida, M.D., Ph.D., F.R.A.N.Z.C.P., of the University of Western Australia, Perth, and colleagues examined 3,987 men age 71 to 89 years, who completed a questionnaire reporting information about demographics and health history.
The researchers tested these men for depression and cognitive difficulties, and information about physical health conditions was obtained from a short survey and an Australian health database.
They also collected blood samples from the participants and recorded levels of total testosterone and free testosterone, which is not bound to proteins.
Almeida and colleagues found that a total of 203 of the participants met criteria for depression - they had significantly lower total and free testosterone levels then men who were not depressed.
The researchers found that after controlling for other factors like education level, body mass index and cognitive scores, men in the lowest quintile (20 percent) of free testosterone concentration were three times more likely to have depression as compared to men in the highest quintile.
During the study, the researchers noted that the mechanism by which low hormone levels might affect depression risk has not been identified, but might involve changes in the levels of neurotransmitters or hormones in the brain.
"A randomized controlled trial is required to determine whether reducing prolonged exposure to low free testosterone is associated with a reduction in the prevalence of depression in elderly men," the authors said.
"If so, older men with depression may benefit from systematic screening of free testosterone concentration, and testosterone supplementation may contribute to the successful treatment of hypogonadal [with low hormone levels] older men with depression," they added.
The study is published in the March issue of Archives of General Psychiatry, one of the JAMA/Archives journals.