Effect of Anorexia Nervosa on Volumetric Bone Mineral Density

It was widely acknowledged that patients with anorexia nervosa (AN) present a decrease in areal bone mineral density (aBMD), but the effect on bone microarchitecture and other parameters associated with fracture risk have been less well investigated. The two aims of this study were to (i) compare aBMD at various bone sites as determined by DXA, as well as trabecular and cortical volumetric BMD (vBMD) at femoral regions using 3D-Shaper® software, in young women with AN and normal-weight controls (CON) and (ii) determine the factors potentially associated with aBMD and vBMD. Three hundred young women from 18 to 35 years old were enrolled in this study: 209 patients with AN and 91 age-matched normal-weight controls. aBMD was determined with DXA and vBMD by 3D-Shaper® software. Compared with controls, patients with AN presented significantly lower aBMD at all bone sites, but the difference was greater at hip and lumbar spine compared with radius. In whole proximal femur and all femoral compartments, vBMD was also lower in patients, but the difference between groups was greater for cortical vBMD compared with trabecular vBMD. Cortical thickness was also altered but to a lower extent. The bone deterioration induced a decrease in bone structural parameters. In the patients, the independent variables for determining aBMD and vBMD were principally minimal disease-related BMI, menstrual disorder status and duration of amenorrhea. This study confirmed not only that young women with AN present lower aBMD across the skeleton, but it also showed for the first time a concomitant deterioration in trabecular and cortical vBMD and cortical thickness as measured by 3D-Shaper®, leading to a decrease in bone structural parameters. In future, it will be interesting to determine whether 3D-Shaper® parameters are more sensitive than aBMD for monitoring skeletal changes due to weight variations or during therapeutic interventions. It will also be relevant to assess whether these new bone parameters are more predictive of fracture risk than aBMD in these patients.