The Effect of Testosterone Replacement on Bone Mineral Density in Boys and Men With Anorexia Nervosa

The Effect of Testosterone Replacement on Bone Mineral Density and Bone Microarchitecture in Teenage Boys and Young Adult Men With Anorexia Nervosa

Decreased bone strength is a common and serious medical problem present in many people with anorexia nervosa. Men with anorexia nervosa have lower levels of gonadal steroids such as testosterone. Low testosterone levels have been shown to result in low bone density. We are investigating whether bone mineral density and bone microarchitecture are abnormal in males with anorexia nervosa and whether supplementation with testosterone would improve both bone mineral density and bone microarchitecture.

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.

Inclusion Criteria: Anorexia Nervosa Teenage boys and young adult men, age 14-30 years Hypogonadism indicated by a testosterone level within the lower 25th percentile for pubertal stage or below normal for pubertal stage Exclusion Criteria: Disease or illness known to affect bone metabolism Use of medications known to affect bone metabolism, such as corticosteroids or androgenic steroids, within 3 months of study initiation Subjects with a z-score less than -2.5 on DXA secondary to concerns of severely low bone mineral density which may require aggressive monitoring

Misra M, Katzman DK, Cord J, Manning SJ, Mendes N, Herzog DB, Miller KK, Klibanski A. Bone metabolism in adolescent boys with anorexia nervosa. J Clin Endocrinol Metab. 2008 Aug;93(8):3029-36. doi: 10.1210/jc.2008-0170. Epub 2008 Jun 10.