AR and hypogonadism: The general role of androgens in bone metabolism, loss of bone mass in cases of hypogonadism, and reduction in bone turnover with testosterone treatment all lead to predictions for a decrease in bone mass density (BMD) and increase in osteoporosis (femoral neck BMD <0.56 g/cm2) with longer AR CAGn (Zitzmann et al. 2001b; Zitzmann 2009).