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/m2, 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/m2. TT and FT levels were inversely related to BMI (-0.48, p<0.0001). Total testosterone was subnormal in 57.5% 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. CONCLUSION 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.