Battle of the sex steroids in the male skeleton: and the winner is...

Male osteoporosis is a multifactorial disease, although it is often in part related to hypogonadism. While testosterone replacement therapy has been shown to improve bone mineral density, studies have also linked bone loss and higher fracture risk in men to low estrogen levels. In this issue of the JCI, Finkelstein and colleagues report the results of a clinical study in a cohort of healthy adult men aimed at further discerning the specific roles of androgen and estrogen deficiency in bone loss. The results of their study support previous findings that estrogen deficiency has a dramatic effect on bone homeostasis in men. Future studies to corroborate and expand on these findings have potential to influence the clinical management of male osteoporosis.