Changes in Bone Turnover in Patients with Anorexia Nervosa during Eleven Weeks of Inpatient Dietary Treatment

Abstract

Abstract Background: Many adolescents with anorexia nervosa suffer from severe osteopenia and osteoporosis. We hypothesized that individualized nutrition therapy may improve bone turnover in anorectic patients. Methods: We studied 19 female patients [mean age, 14.2 ± 1.4 years; mean body weight, 39.3 ± 5.4 kg; mean body mass index (BMI), 14.2 ± 1.4 kg/m2] with anorexia nervosa (International Classification of Diseases-10: F50.0, F50.1) for a period of 3 months. Nutrition therapy began at the end of the first week and included individualized hypercaloric diets, high calcium intake (2000 mg/day), and administration of vitamin D (400 IU/day). Blood samples were taken at baseline and again in weeks 3, 7, and 11. We measured serum calcium, parathyroid hormone, bone formation and resorption markers, insulin-like growth factor 1 (IGF-1), and leptin. Results: Mean BMI increased significantly, from 14.2 ± 1.4 to 17.1 ± 0.7 kg/m2 (P = 0.000001), during the course of treatment, whereas serum total calcium and phosphate concentrations remained unchanged. The bone formation markers procollagen-I carboxy-terminal propeptide and bone alkaline phosphatase almost doubled (P = 0.006). Both IGF-1 (P = 0.00001) and leptin (P = 0.000005) increased significantly by week 11. Parallel to this, the serum concentration of C-telopeptide, a bone resorption marker, decreased significantly (P = 0.009). Conclusions: Nutritional rehabilitation, possibly as a result of increasing IGF-1 and leptin concentrations, may increase bone formation. It therefore provides additional objective evidence of the importance of nutrition for bone.