Paresh Dandona and Sandeep Dhindsa wrote this update on hypogonadotropic hypogonadism (HH) in type 2 diabetes and obesity. They review current literature and offer suggestions for further research to advance understanding of acquired HH.
Several studies over the last few years have confirmed that HH is present in 25-40% of men with type 2 diabetes. Because of this high prevalence, The Endocrine Society has made recommendation to measure testosterone levels in all male patients with type 2 diabetes.
Dandona and Dhindsa used liquid chromatography tandem mass spectrometry assay. The reference ranges for total and free testosterone have been adjusted downward, and Dandona and Dhindsa used these new ranges to estimate HH prevalence. They found HH to be present in 25% of men with type 2 diabetes.
Another 4% of men had hypergonadotropic hypogonadism (subnormal testosterone with elevated LH and FSH concentrations).
Subnormal testosterone is not related to glycosylated hemoglobin or duration of diabetes. It is associated with:
Two earlier studies showed that men with low testosterone are at a 2 to 3 times elevated risk for cardiovascular events and death.
Men receiving testosterone therapy have shown an increase in insulin sensitivity, as well as a decrease in waist circumference.
They have also shown an increase in libido but not an improvement in erectile dysfunction; phosphodiesterase inhibitors may be needed.
Data are mixed on the effect of testosterone therapy on glycemic control and cardiovascular risk.
Dandona and Dhindsa suggest that more trials—particularly those of longer duration—are needed in order to better understand the risks and benefits of testosterone therapy for patients with subnormal testosterone and type 2 diabetes.
Commentary by Glenn R. Cunningham MD