High prevalence of hypogonadotropic hypogonadism in men referred for obesity treatment

Background: Obesity can be associated with biochemical evidence of isolated hypogonadotropic hypogonadism (IHH) in men. Prevalence and severity of IHH in obese men are not exactly known. Objective: To assess the prevalence of IHH in obese men. Design and Subjects: Cross-sectional study of 160 obese men, BMI >30 kg/m(2), who applied for medical or surgical treatment of obesity in a general teaching hospital. Main outcome measures: Total and calculated free testosterone (TT and FT) in relation to body mass index (BMI). Results: Mean age of the study population was 43.3 +/- 0.8 years (mean +/- SEM), BMI ranged from 30.0 to 65.7 kg/ m(2). TT and FT levels were inversely related to BMI (-0.48, p<0.001). Total testosterone was subnormal in 57.7% and free testosterone in 35.6% of the subjects. The group of men with IHH was more obese, had higher HbA(IC) levels and had a 2.6 higher risk for cardiovascular disease. Decreased libido and erectile dysfunction were 7.1 and 6.7 times as common in IHH than in eugonadal obese men. Conclusions: Reduced T levels, well into the hypogonadal range, are common in male obesity. Assessment of its clinical implications, and a search for the best mode of treatment are warranted.