Ageing male (part I): Pathophysiology and diagnosis of functional hypogonadism

This narrative review summarizes key points of the pathogenesis and diagnosis of the ageing-related decline of testosterone (T) in men. The condition is commonly termed late-onset hypogonadism (LOH), but because it is more often caused by other factors than chronological ageing (obesity and other comorbidities), a more appropriate term is functional hypogonadism (FH). Unlike the classical organic hypogonadism, no anatomical or genetic aberra-tions are found in FH, and the suppression of T is milder. Moreover, FH can be reversible if the underlying cause (e.g. obesity, chronic disease) is removed/treated. Low serum total T in connection with more specific hypogonadism-associated symptoms (primarily sexual) form the basis of the diagnosis of FH. When T concentra-tions are borderline, the accuracy of diagnosis can be improved by assessment of free or calculated free T, especially when suppressed SHBG levels (usually related to obesity) are likely. Current data indicate that FH (low T and sexual symptoms) is not a common condition, and it is detectable in about 2% of community-dwelling men aged 40e80 years.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This narrative review provides an overview of the pathogenesis and diagnosis of the decline in testosterone levels in men associated with aging. The condition, commonly referred to as late-onset hypogonadism (LOH), is more appropriately termed functional hypogonadism (FH) as it is often caused by factors other than chronological aging, such as obesity and other comorbidities. Unlike classical organic hypogonadism, FH does not involve anatomical or genetic abnormalities and the suppression of testosterone is milder. Furthermore, FH can be reversible if the underlying cause, such as obesity or chronic disease, is treated. The diagnosis of FH is based on low serum total testosterone levels and specific hypogonadism-associated symptoms, primarily sexual symptoms. When testosterone concentrations are borderline, the accuracy of diagnosis can be improved by assessing free or calculated free testosterone, especially when sex hormone-binding globulin levels are likely suppressed due to obesity. Current data indicate that FH, characterized by low testosterone levels and sexual symptoms, is not a common condition and is present in approximately 2% of community-dwelling men aged 40 to 80 years.