Low bone mineral density is a co-morbidity associated with anorexia nervosa that has been shown to persist even after weight gain. Peak bone mass accrual occurs during the adolescent years, and a disruption in this critical process increases the risk for developing persistent deficits in bone density, and possibly increased fracture risk. Multiple variables contribute to the bone mass accrual process in puberty including adequate levels of sex hormones and puberty specific changes in levels of these hormones. Teenage boys with anorexia nervosa have lower bone density than normal weight boys of comparable maturity, and also have decreased levels of testosterone, as well as estradiol, when compared with healthy controls. Although testosterone is an important predictor of bone density in males with anorexia nervosa, the effect of testosterone replacement on bone mass accrual and bone microarchitecture in hypogonadal teenage boys and young adult men with anorexia nervosa is unknown. We hypothesize both bone mass and bone microarchitecture are abnormal in anorexia nervosa and that testosterone replacement in adolescent males with anorexia nervosa will improve both bone mass and microarchitecture.
