Low testosterone in the aging man: A normal process or an endocrine disease

Abstract

The aging process has only a marginal effect on circulating testosterone (T). In fact, the increasing prevalence of T deficiency as a factor of age is mainly explained by the greater prevalence of chronic morbidities, in particular of metabolic disturbances such as type 2 diabetes mellitus, obesity and metabolic syndrome. The latter conditions are associated with both primary and secondary hypogonadism (HG), while an age-related effect on T levels is evident only for primary hypogonadism. Considering that secondary HG is the most common form of T deficiency in the aged man, it is derived that the independent contribution of aging to T deficiency is negligible. Hence, a true “andropause” does not exist. A FDA position and some recent guideline suggest that only “organic” form of HG should be treated, whereas T deficiency associated to obesity and other comorbidities should be left untreated and the underlying conditions removed. In the Florence experience this is tantamount to say that 85% of HG subjects complaining for sexual dysfunction should not receive T therapy (TTh) because they are not satisfying criteria for “organic” HG. However, meta-analysis of randomized controlled trials (RCTs) – enrolling, for the large majority, patients without an “organic” form of HG – indicates that TTh is able to significantly increase sexual desire and improve erectile dysfunction and orgasm. In addition, TTh is associated with a reduction of fat mass and an increase in lean mass, with an overall improvement in glucose metabolism. Nonetheless, effect of TTh is more apparent in trails of longer duration and in those enrolling subjects without diabetes or obesity at baseline.