Perspectives

Understanding functional hypogonadism – serum testosterone as a marker of chronic disease and cardiometabolic risk in men

Perspectives

Understanding functional hypogonadism – serum testosterone as a marker of chronic disease and cardiometabolic risk in men

Gary Wittert

Figures

© ediebloom/istockphoto.com model used for illustrative purposes only
© ediebloom/istockphoto.com model used for illustrative purposes only

Abstract

In men with obesity, a low serum testosterone concentration in the absence of pathology of the hypothalamic-pituitary-testicular axis is termed functional hypogonadism and is mostly due to obesity. Such a finding should prompt a comprehensive assessment for underlying chronic disease and cardiometabolic risk.

Key Points

  • Ageing in men is not inherently associated with a significant decrease in serum testosterone concentrations until the process is very well advanced (>80 years).
  • Obesity, where the excess fat is stored in viscerally located adipose tissue and associated with insulin resistance, dyslipidaemia and inflammation, decreases serum testosterone concentration by both central and peripheral mechanisms.
  • The low serum testosterone concentration resulting from obesity is reversible with weight loss and is therefore best thought of as obesity-associated functional hypogonadism.
  • Men with visceral obesity, the metabolic syndrome and low serum testosterone concentrations are at increased risk for type 2 diabetes.
  • Other causes of functional hypogonadism include medication (opioids), smoking cessation, excess alcohol consumption, inflammatory processes and subtypes of depression.
  • A low serum testosterone concentration caused by a definable abnormality in the hypothalamus, pituitary or testes is termed pathological hypogonadism.
  • The finding of a low serum testosterone concentration requires a thorough clinical and endocrinological assessment to establish the reason it is low, and treatment instituted accordingly.