Bone Abstracts

Objectives: Patients with anorexia nervosa (AN) are at high risk of reduced bone mass. The aim of this intervention study was to investigate the long-term effects on bone and body composition three years after intense weight gain therapy.

Methods: Twenty-five female AN patients, mean age 20.1 years, mean BMI of 15.5 kg/m², were included. Twenty-two patients fulfilled the treatment for 12 weeks with a high-energy diet. Body composition and bone mass were assessed by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography at start, 12 weeks and 20 patients were evaluated after 3 years. Serum sclerostin was assessed by ELISA.

Results: During the 12 week therapy, mean BMI increased from 15.5 to 19.0 kg/m², P<0.001, and remained stable during 3 years. Fat mass increased from 14.0% to 26.3% during the intervention period and remained stable over 3 years. Lean mass was unchanged during the study period. The mean fat/muscle area was 22.7% at baseline and increased to 31.7% after 12 weeks therapy, P<0.001, and remained stable over 3 years. The mean baseline values were, for total body BMD 1.1 g/cm², lumbar spine BMD 1.0 g/cm², lumbar spine BMC 53.8 g, which did not change over the study period. Total body BMC, 2195 g at baseline, increased to 2287 g during the 12-week intervention (P=0.002) but decreased after 3 years to 2215 g (P<0.05). The mean tibial trabecular density (4%) was 237 mg/cm³ at baseline and decreased to 222 mg/cm³ after 12 weeks, P<0.001, which further decreased to 207 mg/cm³, P=0.01. The mean tibial cortical density (66%) was 1153 mg/cm³ at baseline and was unchanged over 3 years. The highest level of sclerostin was observed at baseline, mean 30.1 pmol/l, which decreased after 12 weeks and 3 years to 27.1 pmol/l and 21.7 pmol/l, respectively, P<0.05.

Conclusion: Tibial trabecular density decreased even though areal BMD was unchanged. The reduction in sclerostin implies a possible compensatory mechanism to increase bone formation on the cellular level. This study indicates the importance of long-term follow-up of bone health in young women with severe AN, although stable BMI values were achieved.

Disclosure: The authors declared no competing interests.