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

Abstract

Osteopenia and osteoporosis are among the most frequent and severe complications in adolescents with anorexia nervosa. The aim of this study was to assess the influence of nutritional therapy on bone metabolism during adolescent anorexia nervosa. We studied 19 anorectic patients aged 14.1 +/- 1.4 y (x +/- 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. 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). Nutritional therapy improves concentrations of bone formation markers in adolescent patients with anorexia nervosa.