Serum total testosterone level and identification of late-onset hypogonadism: a community-based study

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.

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.

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.

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.