Serum Total Testosterone Level and Identification of Late-Onset Hypogonadism: A Community-Based Study

PURPOSE: Late-onset hypogonadism (LOH) in aging males is a clinical and biochemical syndrome characterized by a decline in serum testosterone levels. LOH results in various physical and mental disabilities. We evaluated the relationship between serum testosterone levels and symptoms of LOH. MATERIALS AND METHODS: During an andropause screening program, we examined responses to the Saint Louis university androgen deficiency in aging males (ADAM) questionnaire and results on the International Index of Erectile Function (IIEF-5) in terms of clinical symptoms and evaluated serum total testosterone levels for a biochemical diagnosis of LOH in healthy community-living volunteers aged over 40 years. RESULTS: The mean age of the 534 men was 59.1 years (range, 40 to 79 years), and their mean serum testosterone level was 464.1±171.9 ng/dL. The serum testosterone level decreased significantly with age. There was a 92.5% positive response rate to the ADAM questionnaire. The percentage of patients whose serum testosterone level was <350 ng/dL among those with a positive response to the ADAM questionnaire was 25.6% (137 patients). The mean serum testosterone level among patients with a positive or negative ADAM questionnaire was 472.4±198.5 ng/dL and 487.3±165.7 ng/dL, respectively (p>0.05). There was no significant correlation between IIEF-5 scores and serum testosterone levels. CONCLUSIONS: Among men over 40 years of age, 25.6% met the clinical and biochemical diagnostic criteria for LOH. There was no relationship between serum testosterone levels and symptoms of LOH.