Purpose of review: To examine bone health in relation to testosterone and male hypogonadism.
Recent findings: An emerging area of research pertains to the newly described bone-testis axis. In particular, the peptide hormone osteocalcin, which is made by bone and fat, appears to play a role in testosterone production. Inconsistent weak associations have been noted between vitamin D deficiency or insufficiency and lower testosterone levels. Although a high prevalence of hypogonadism is associated with opioid use, HIV and transfusion-dependent thalassemia, the risk of fracture in these populations is unclear. In fact, one study found that the modest increase in fractures among opioid users was attributed to central nervous system adverse effects of the medications as opposed to chronic hypogonadism. In terms of therapy, many small studies have found that testosterone replacement therapy increases bone mineral density in hypogonadal men, including men with hypopituitarism.
Summary: Further research is needed on the cross-talk that occurs in the bone-testis axis. When it comes to managing men with hypogonadism, the benefit of testosterone replacement therapy on prevention of incident fractures is uncertain. Large, long-term randomized controlled trials are needed with fracture as the primary outcome.