Reduced bone mineral in patients with eating disorders.

Bone mineral measurements of the forearm and spine were made in 63 patients under treatment in the Eating Disorders Program of the University of Nebraska Medical Center, 26 with anorexia nervosa (AN), 11 with bulimia nervosa (BU) and 26 with features of both AN and BU (AN/BU). Comparison was made with a group of 211 normal women of similar age. Spinal bone mineral content (BMC) of L2-4 was 45.1 +/- 5.7 g in the normals, 38.0 +/- 7.5 in the AN's, 40.3 +/- 6.6 g in the AN/BU's and 44.4 +/- 6.9 g in the BU's. The AN and AN/BU averages were both significantly different from normal (p less than 0.0005), but the BU average was not. BMC was correlated with body weight in each group and weakly correlated with age in the patients under age 30 in the AN and AN/BU groups combined. Forearm bone mineral measurements in the AN's and AN/BU's were also significantly lower than normal, but the differences were not as great as for the spine. We conclude that bone mineral is reduced in these patients, severely in some of them, and that reduced body weight plays a role. Menstrual disturbances, inhibition of growth and development, and malnutrition remain open as causal factors. Potential for recovery from reduced bone mineral was not demonstrated in this study.