Dominguez J et al. (2007) Treatment of anorexia nervosa is associated with increases in bone mineral density, and recovery is a biphasic process involving both nutrition and return of menses. Am J Clin Nutr 86: 92–99

Women with anorexia nervosa commonly experience bone loss and are at high risk of osteoporosis at menopause. Treatments aimed at increasing bone mass in women with anorexia nervosa include estrogen replacement and oral contraceptives, but these treatments lack effectiveness. Dominguez and colleagues conducted a longitudinal study in women with anorexia nervosa before and after their weight was normalized by treatment, with the aim of better understanding the mechanisms underlying bone loss and its reversal in these patients.

The authors studied 28 patients with anorexia nervosa (all but one amenorrheic at admission) who underwent a behavioral weight-gain protocol that involved reaching at least 90% of their ideal body weight (IBW). The control group consisted of 11 healthy volunteers matched with patients who had anorexia nervosa by age and IBW and 30 reference individuals from a prior study. From admission to recovery of IBW, the BMD of patients with anorexia nervosa increased significantly. Levels of osteocalcin, a marker for bone formation, also increased with weight gain. Levels of the marker for bone resorption, N-telopeptide, were higher in patients with anorexia nervosa at admission relative to control and reference control individuals, but decreases in N-telopeptide occurred after successful treatment only in those patient who regained menses (n = 8).

The authors suggest that recovery of BMD in patients with anorexia nervosa is biphasic, requiring nutritional rehabilitation to stimulate bone formation, and then a hormonal mechanism to decrease bone resorption. On the basis of these findings the authors suggest re-examining the use of antiresorptives for these patients.