Male hypogonadism and skeletal health.

PURPOSE OF REVIEW: To examine the role of testosterone in skeletal health in men.

RECENT FINDINGS: Evidence from recent studies shows that the contributing role of testosterone to osteoporosis is modest and likely trumped by other factors such as estradiol levels. A few studies have documented an association between low testosterone levels and lower bone mineral density (BMD), increased prevalence of osteoporosis of the hip and low bone mass-related fractures. Other studies, however, have found that testosterone levels are not independent predictors of bone resorption or formation markers, BMD at the hip or incident fractures. Curiously, hypogonadism does not account for the increased osteoporosis seen in men with Klinefelter Syndrome. Regardless of hypogonadism status, two recent clinical trials have found fewer new morphometric vertebral fractures in men treated with zoledronic acid and increased BMD in men treated with denosumab. Denosumab was also shown to modestly increase bone-metastasis-free survival in men with castration-resistant prostate cancer.

SUMMARY: Although male hypogonadism is associated with osteoporosis, estradiol is likely to be the more important hormone for bone health. Although a few large randomized controlled trials have been conducted in men with low bone density (a subset of whom have hypogonadism), more trials are needed, particularly with fractures as the main outcome.