Bone and vitamin D status in patients with anorexia nervosa.

INTRODUCTION

The aim of the present study was to investigate bone status and biological mechanisms involved in the negative impact of anorexia nervosa (AN) on osteogenesis.

METHODS

A total of 30 AN patients from Aalborg University Hospital who underwent bone scans were included in a cross-sectional study. Biochemical data, bone scans (dual-energy X-ray absorptiometry (DXA)) as well as general health and medical information had been collected during the 2009-2011 period and stored via local and national clinical databases in Denmark, and from these databases we identified all patients with an AN diagnosis who underwent bone scans.

RESULTS

AN patients had a mean Z-score of -1.5 to -1.6 in lumbar spine and total hip, respectively. The hip Z-score decreased with duration of disease, and a positive correlation was seen between serum 25-hydroxy-vitamin D level and spine Z-score but not hip Z-score. Bone mineral density did not seem to change with time since diagnosis. Additionally, a negative correlation between serum 25-hydroxy-vitamin D levels and serum total alkaline phosphatase levels was found. A serum 25-hydroxy-vitamin D level below 50 nmol/l was associated with increased alkaline phosphatase levels.

CONCLUSION

Rather than clinical measures including BMI and biochemical measures disease duration was the main predictor of bone status. This implies that long-term disease should be a main factor in selecting patients for referral to DXA. Moreover, results from this study indicate normal osteoblastic response to malnutrition.

FUNDING: not relevant.

TRIAL REGISTRATION: The present study was not registered due to its register-based design. However, the study was approved by the Danish Data Protection Agency.