A new study has shown that older men with lower free
testosterone levels in their blood appear to have higher prevalence of
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
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
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.