Frequent Occurrence of Hypogonadotropic Hypogonadism in Type 2 Diabetes

Dhindsa S, Prabhakar S, Sethi M, Bandyopadhyay A, Chaudhuri A, Dandona P. J Clin Endocrinol Metab. 2004;89:5462-5468.

Hypogonadism can have a number of clinical consequences, including decreased libido, erectile dysfunction, increased fat mass, decreased muscle mass, and decreased bone density. The results of this study suggest hypogonadism is common among men with type 2 diabetes, regardless of glycemic control, duration of diabetes, or the occurrence of complications associated with obesity or diabetes. In total, 103 male patients attending a diabetes clinic in Buffalo, New York participated in the study. The mean age of subjects was 54.7±1.1 years (range = 28 to 80 years), and the average duration of diabetes was 7.7±0.7 years (range = 0.1 to 36 years).

In normal circulating blood, 2% of testosterone is free, 44% is bound with sex hormone-binding globulin (SHBG), and 54% is bound with albumin or other proteins. Mean total testosterone was 12.19±0.50 nmol/L; 43.7% of subjects had total testosterone levels <10.4 nmol/L. Mean free testosterone was 0.250±0.014 nmol/L; 24.6% of subjects had levels <0.174 nmol/L, considered hypogonadal. Mean SHBG was 27.89±1.65 nmol/L and average calculated free testosterone (cFT; calculated based on total testosterone and SHBG levels) was 0.269±0.012 nmol/L; 36% of subjects had cFT levels <0.225 nmol/L, considered hypogonadal. Based on these results, 33% of patients overall were considered hypogonadal. Both total testosterone levels and SHBG were found to be inversely correlated with weight and body mass index. In addition, luteinizing hormone and follicle-stimulating hormone levels were significantly lower in hypogonadal subjects compared with eugonadal subjects.

The testosterone levels of this study population are lower than those of the general population. For example, bioavailable levels of testosterone in this study population in comparison with those of 400 male subjects in a study carried out by Muller and colleagues were lower for all age groups: age 40 to 50 years, 6.36 vs 9.90 nmol/L; age 51 to 60 years, 6.56 vs 8.40 nmol/L; age 61 to 70 years, 5.70 vs 7.40 nmol/L; age 71 to 80 years, 5.63 vs 7.00 nmol/L.[1]

In summary, hypogonadism is common among men with type 2 diabetes, occurring in 33% of subjects in this study population. The etiology of hypogonadism in type 2 diabetes as well as the potential consequences and treatment merit further consideration in future studies.

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