Newswise — Testosterone deficiency, previously recognized as common in men with type 2 diabetes, is also common in men with type 1 diabetes according to a new study accepted for publication in the Journal of Clinical Endocrinology & Metabolism (JCEM). These findings suggest that there is a direct link between insulin resistance and reduced testosterone levels in men.

“As testosterone deficiency may contribute to impaired performance, mood, and libido, as well as have adverse impact on cardiovascular risk, these findings demonstrate the presence of a significant and unrecognized problem among men with diabetes,” said Dr. Mathis Grossmann of the University of Melbourne in Australia. “Our findings of insulin resistance as a potential determinant of reduced testosterone levels may represent an important avenue for intervention.”

For this study, researchers conducted a survey of 580 men with type 2 diabetes and 69 men with type 1 diabetes. A subgroup of 262 men with type 2 diabetes was then reassessed after six months. Testosterone levels were measured from blood samples using the Access testosterone assay.

Previous population-studies found an association of reduced testosterone levels in men and type 2 diabetes, however this is the first study to demonstrate a similar prevalence in individuals with type 1 diabetes.

This study raises the question of whether testosterone replacement therapy can reduce insulin resistance or symptoms of hypogonadism in men with diabetes. Researchers, however stress that the balance of benefits and risks of such treatment is currently unknown and still to be defined by large and long-term clinical trials. Also, while insulin resistance is associated with testosterone deficiency, there is no evidence that insulin sensitizers are able to elevate testosterone levels in men with diabetes.

Other researchers working on the study include Merlin Thomas, Sianna Panagiotopoulos, Ken Sharpe, Richard MacIsaac, Sophie Clarke, Jeffrey Zajac, and George Jerums of the University of Melbourne in Australia.

A rapid release version of this paper has been published on-line and will appear in the May 2008 issue of JCEM, a publication of The Endocrine Society.