Aging and sex hormones in males

Abstract

Several large cohort studies have disclosed the trajectories of sex steroids changes overtime in men and their clinical significance. In men the slow, physiological decline of serum testosterone (T) with advancing age overlaps with the clinical condition of overt, pathological hypogonadism. In addition, the increasing number of comorbidities, together with the high prevalence of chronic diseases, all further contribute to the decrease of serum T concentrations in the aging male. For all these reasons both the diagnosis of late-onset hypogonadism (LOH) in men and the decision about starting or not T replacement treatment remain challenging. At present, the biochemical finding of T deficiency alone is not sufficient for diagnosing hypogonadism in older men. Coupling hypogonadal symptoms with documented low serum T represents the best strategy to refine the diagnosis of hypogonadism in older men and to avoid unnecessary treatments.

Keywords: bone mineral density; estradiol; late-onset hypogonadism (LOH); menopause; replacement treatment; sex steroids; testosterone.

Figure 1.

Serum levels of both testosterone (T) (solid lines) and estradiol (E₂)* (broken lines) across the lifespan in men (blue lines) and women (pink lines). Data used for plotting age-related sex steroids changes in both sexes have been derived from Kaufman & Vermeulen 2005⁵, Zmuda et al. 1997⁶ (for men), and from Al-Safi et al. 2000² and Veldhuis 2013 (for women). serum E₂ levels of premenopausal women are represented as the mean of E2 measured during the different phases of the menstrual cycle; T: testosterone; E₂: estradiol.

Figure 2.

Classification of hypogonadism according to its pathogenesis.

Figure 3.

Signs and symptoms of late-onset hypogonadism according to their specificity.