Bone mineral density in anorexia nervosa: Only weight and menses recovery?

Introduction: The study objectives were to analyze the presence of reduced bone mass in a sample of patients with anorexia nervosa (AN) and amenorrhea, to assess Bone Mineral Density (BMD) recovery after having a normal weight is reached and regular menses are resumed, and to predict BMD after a treatment period considering different variables (baseline BMD, baseline and final body mass index (BMI), treatment duration).

Material & Methods: 35 patients with AN (mean age 20.57±5.77) were studied at treatment start (T) and after they had recovered their normal weight and regular menses (T) in order to measure their BMD using quantitative computed tomography (QCT) of the lumbar spine (L2-L4).

Results: At T, 2.86% of patients had normal BMD, while a reduced bone mass consistent with osteopenia or with osteoporosis was found in 22.86% and 74.28% of patients respectively. At T, the percentages were 20%, 20%, and 60% respectively. No significant differences were seen in L2-L3 and mean BMD (L2-L4). A significant difference was however found for L4 (p<0.05). A positive relationship was seen between final body mass index (BMI) and final BMD in patients with T-T>11 months, but not when the time period was ≤11 months.

Conclusions: This follow-up study of changes not only in BMD but also in BMI and recovery of menses has clinical relevance from the viewpoint of the day-by-day treatment process. Use of QCT makes the study more relevant because this is a more advanced technique that allows for differentiating trabecular and cortical bone.