Abstract
Late-onset hypogonadism (LOH) as “a clinical and biochemical syndrome associated with advancing age and characterized by typical symptoms and a deficiency in serum testosterone levels. It may result in significant detriment in the quality of life and adversely affect the function of multiple organ systems” was defined. Therefore, the basis of diagnosis of LOH is the measurement of androgen levels. In Japan, as specified in the “Clinical Practice Manual for LOH Syndrome” it has been decided to recommend the measurement of free testosterone (free T) levels as a diagnostic test for LOH. The standard value for diagnosis of LOH is set at a mean–2SD value of 8.5 pg/mL, by calculating the mean value in young adults in their 20s (young adult mean: YAM). The symptom most closely associated with hypogonadism is said to be low libido. Other symptoms associated with hypogonadism include erectile dysfunction, decreased muscle mass and strength, increased body fat, decreased bone mineral density and osteoporosis, decreased vitality, and impaired mood. In Japan, the use of the YAM of free T in the standard diagnostic criteria for LOH has been proposed. However, it should be verified that free T is clinically applicable as a criterion for determining the LOH cases to be indicated for ART. In addition, it is required to clarify whether normalization of androgen levels by ART can lead to improvement of symptoms.
