Hypogonadism A Common Complication Of Diabetes

29 November 2004
Hypogonadism A Common Complication Of Diabetes
by George Atkinson

A new study - appearing in the Journal of Clinical Endocrinology and Metabolism - suggests that low testosterone production appears to be a common complication of type 2 diabetes in men, affecting 1 out of 3 patients. Known clinically as hypogonadism, the condition is caused not by a defect in the testes, where testosterone is produced, but by improper functioning of the pituitary gland, which controls the production of testosterone, or of the hypothalamus, the part of the brain that controls the pituitary gland.

First author on the study, Sandeep Dhindsa, said the findings are important because hypogonadism has not been recognized as a complication of type 2 diabetes, and the prevalence of 30 percent was not anticipated.

"The surprisingly high prevalence of low testosterone levels was associated with lower levels of pituitary hormones called gonadotrophins, suggesting that the primary defect in these patients was either in the pituitary or higher up in the hypothalamus," he said. "Since gonadotrophins drive the testes to produce testosterone, this finding gives us an insight into the pathogenesis of this complication of type 2 diabetes."

The study results showed that nearly one-third of the men tested had hypogonadism. Although obesity is associated with hypogonadism and is prevalent among type 2 diabetics, only 10-15 percent of the variation in low free testosterone levels could be attributable to body mass index, Dhindsa said. More than 30 percent of lean patients also were hypogonadal. "Equally important, most of the men who had low testosterone levels also had lower levels of gonadotrophins, as compared to men with normal testosterone levels," he said. "Furthermore, the gonadotrophin concentration in the blood correlated positively with free testosterone levels, supporting the notion that the cause of the defect is in the pituitary or hypothalamus."

The high prevalence of low testosterone in diabetic men is concerning, said Dhindsa, because in addition to lowered libido and erectile dysfunction, the condition is associated with loss of muscle tone, increase in abdominal fat, loss of bone density, and can affect mood and cognition. "Further studies will help us determine why type 2 diabetic patients are more prone to developing hypogonadism," he said.