Bone turnover during inpatient nutritional therapy and outpatient follow-up in patients with anorexia nervosa compared with that in healthy control subjects

Background: Osteopenia and osteoporosis are among the most frequent and severe complications in adolescents with anorexia nervosa. Objective: The aim of this study was to assess the influence of nutritional therapy on bone metabolism during adolescent anorexia nervosa. Design: We studied 19 anorectic patients aged 14.1 +/- 1.4 y((x) over bar +/- SD) with a body mass index (BMI; in kg/m(2)) of 14.2 +/- 1.4 and 19 age-matched control subjects aged 15.1 +/- 2.3 y with a BMI of 20.8 +/- 1.9 for 1 y. Blood samples were taken for the measurement of bone markers, insulin-like growth factor I (IGF-I), and leptin. Results: BMI rose significantly from 14.2 1.4 at baseline to 17.4 +/- 0.6 (P < 0.0001) at week 15. Compared with concentrations in the control subjects, concentrations of the bone formation markers procollagen type I propeptide (PICP) and bone alkaline phosphatase (bAP) in the anorectic patients were lower at baseline (PICP: P = 0.0071; bAP: P = 0.0012), increased with nutritional therapy (PICP: P = 0.0060, bAP: P = 0.0147), and were no longer significantly different (P > 0.05) during the follow-up period. Concentrations of IGF-I and leptin were significantly lower (P < 0.0001 for both) in the anorectic patients than in the control subjects at baseline. IGF-I increased with nutritional therapy but was still significantly lower (P = 0.0036) than that in the control group and decreased again during the follow-up period (P = 0.0126). In contrast, serum C-telopeptide decreased with nutritional therapy (P = 0.0446). Conclusion: Nutritional therapy improves concentrations of bone formation markers in adolescent patients with anorexia nervosa.