NEW YORK (Reuters Health) – Hypogonadotrophic hypogonadism is present in about a third of men between the ages of 18 to 35 who have type 2 diabetes, researchers report in the October issue of Diabetes Care.

The potential implications for men, in terms of their sexual and reproductive function during prime reproductive years are “profound,” note Dr. Paresh Dandona and colleagues from the State University of New York at Buffalo.

The researchers measured serum concentrations of total and free testosterone in 24 type 2 diabetic men, with a mean age of 28 years and BMI of 39, and 38 type 1 diabetic men, with a mean age of 26 years and BMI of 27.

Total and free testosterone levels were significantly lower in type 2 diabetics than in type 1 diabetics (p < 0.001 for both). Specifically, mean total and free testosterone levels measured 11.14 and 0.296 nmol/L, respectively, in type 2 diabetic men compared with 22.89 and 0.489 nmol/L, respectively, in type 1 diabetic men. Based on usual normal ranges of free testosterone, 33% of type 2 diabetics (8 of 24) were hypogonadal, compared with 8% of type 1 diabetics (3 of 38). Using an age-based reference range, 14 of 24 type 2 diabetics (58%) were hypogonadal, the researchers report. Consistent with previous data, “hypogonadal patients had inappropriately low luteinizing hormone and follicle-stimulating hormone concentrations and thus had hypogonadotrophic hypogonadism,” they note. Mirroring other studies, there was an inverse relationship between BMI and total and free testosterone concentrations. However, while BMI is a “major determinant” of hypogonadotrophic hypogonadism, the association is not entirely dependent on obesity, Dr. Dandona and colleagues say, citing a previous study in which 31% of lean type 2 diabetic men also had hypogonadotrophic hypogonadism. Low testosterone may impair sexual function, reduce libido, and lead to erectile dysfunction, the authors point out. Moreover, low testosterone in young type 2 diabetics may lead to diminished peak bone mass and lack of development or loss of skeletal muscle. “In addition, these patients may develop increased adiposity, and, therefore, may become more insulin resistant.” Type 2 diabetics with hypogonadotrophic hypogonadism have also been shown to have elevated C-reactive protein concentrations, and thus may be at increased risk for cardiovascular disease, the authors note. Reference:
Diabetes Care 2008;31:2013-2017.