Bone mineral density (BMD; measured by DXA) changes were observed at all sites at 1 year in 146 patients with anorexia nervosa. Four independent factors accounted for the variation in BMD at the spine: duration of anorexia, bone-specific alkaline phosphatase (BAP), cross-linked carboxyterminal telopeptide region of type I collagen (ICTP), and triiodothyronine (T3). No change in BMD was observed from 1 to 2 years during follow-up.
Introduction: The purpose of this study was to assess changes in BMD at 1 and 2 years in anorexia nervosa patients, and to explore the relationships between change in BMD and various clinical and biological parameters measured at the first visit.
Methods: BMD was measured in anorexia nervosa patients at inclusion, at 1-year follow-up (n = 146) and at 2-year follow-up (n = 89).
Results: Bone loss was observed at all sites at 1 year. When multivariate analyses were performed, four independent factors accounted for the variation in BMD at the spine: duration of anorexia nervosa, BAP, ICTP, and T3. At the total hip site, leptin level was the main factor accounting for the variation in BMD. Strong correlations were also observed between weight at 1 year and change in BMD at 2 years. At the 2-year follow-up, no significant change in BMD was observed at the spine or femoral neck. In patients who were no longer amenorrheic at 1 year, a significant improvement in BMD at 2 years was observed at the total hip (+1.2%, p = 0.02) and femoral neck (+3.7%, p = 0.02). Similarly, in patients with a body mass index >17 kg/m(2) at 1 year, an improvement in BMD at the total hip at 2 years was observed (+3%, p = 0.02)
Conclusion: Bone loss in anorexia nervosa patients occurs at an early stage, and the factors influencing such are different at the spine and hip.