MINERAL BALANCE AND BONE TURNOVER IN ADOLESCENTS WITH ANOREXIA-NERVOSA

We evaluated seven female adolescents with anorexia nervosa to determi ne whether calcium metabolism was affected by their disorder. We measu red calcium absorption, urinary calcium excretion, and calcium kinetic s, using a dual-tracer, stable-isotope technique during the first week s of an inpatient nutritional rehabilitation program. Results were com pared with those from a control group of seven healthy adolescent girl s of similar ages. The percentage of absorption of calcium was lower i n subjects with anorexia nervosa than in control subjects (16.2% +/- 6 .3% vs 24.6% +/- 7.2%; p <0.05). Urinary calcium excretion was greater in subjects with anorexia nervosa than in control subjects (6.4 +/- 2 .5 vs 1.6 +/- 0.7 mg . kg-1 . day-1; p <0.01) and was associated with bone resorption rather than calcium hyperabsorption. Calcium kinetic s tudies demonstrated a decreased rate of bone formation and an increase d rate of bone resorption. These results suggest marked abnormalities in mineral metabolism in patients with anorexia nervosa. From these re sults, we hypothesize that improvement in bone mineralization during r ecovery from anorexia nervosa will require resolution of hormonal abno rmalities, including hypercortisolism, in addition to increased calciu m intake.