Effects of weight gain and resumption of menses on reduced bone density in patients with anorexia nervosa

The bone mineral density (BMD) of the lumbar vertebrae (L2–L4) and of the whole body were measured in cross-sectional and longitudinal studies in female patients with eating disorders, using dual photon absorptiometry before and after weight gain with or without resumption of menses. In the cross-sectional study, the low-body-weight anorectic patients, with or without bulimia nervosa, were found to have lower BMD of the lumbar vertebrae associated with severe weight loss, low physical activity, and earlier onset and longer duration of amenorrhea. In the longitudinal study, 11 patients attained subnormal body weight (70%SBW < 85% SBW), 10 patients attained normal body weight ( 85%SBW, 6 patients of them resumed regular menses) after treatment. The BMD of the lumbar vertebrae was found to increase with weight gain, but not to the control level. The BMD was further increased with the resumption of menses in patients with anorexia nervosa. These results suggest that resumption of menses, in addition to weight gain, is essential to normalize reduced bone mineral density.