Bone cross-sectional geometry in adolescents and young women with anorexia nervosa: a hip structural analysis study
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Better characterization of bone geometry in adolescents with anorexia nervosa (AN) may improve understanding of skeletal deficits in this population. Our objective was to determine whether hip cross-sectional geometry and bone strength were altered in adolescents with AN.
Measurements of the left total proximal femur and body composition were obtained in 85 adolescents with AN and 61 healthy controls by dual X-ray absorptiometry. The Hip Structural Analysis (HSA) program was used to determine aBMD, cross-sectional area (CSA), and section modulus (Z) at the femoral neck and shaft. Strength indices were calculated and corrected for lean mass.
Femoral neck and shaft aBMD were lower in AN patients than healthy controls (−36% and −29%, p < 0.001). In both regions, bone CSA and Z were lower in AN sufferers (−11 to −35%, p < 0.001). While lean body mass correlated with HSA variables (r = 0.48 to 0.58, p < 0.001), body fat did not. AN sufferers had lower indices of both whole bone strength (−40%, p < 0.001) and relative bone strength (−36%, p < 0.001) than controls.
Anorexia nervosa sufferers had decreased resistance to axial (CSA) and bending loads (Z) compared with healthy controls. Differences in strength properties were significant even when adjusted for lean mass, suggesting that not only decreased mechanical loading, but also known metabolic differences are likely responsible for deficits in bone strength in these patients.
KeywordsAdolescents Anorexia nervosa Bone geometry Bone strength Malnutrition
We gratefully acknowledge Julie Ringelheim, Natalie Glass, Suzanne Muggeo, Diane DiFabio, and Jessica Sexton for outstanding technical assistance; the excellent skill and care of the GCRC nurses at the Children’s Hospital Boston; and our patients who made this study possible. Funding for this study was provided by: RO1 HD043869 from the NICHD; NIH/NCRR Grant MO1-RR-2172 to the Children’s Hospital Boston General Clinical Research Center; Department of Defense, US Army Bone Health and Military Readiness Program; and Project 5-T71-MC-00009-14 from the Maternal and Child Health Bureau.
Conflict of interest statement
The Hip Structure Analysis software developed by Dr. Beck has been licensed by Johns Hopkins University to Hologic, Inc. Dr. Beck has received research support from Eli Lilly, Aventis, NPS Pharmaceuticals, Amgen, and Merck, Inc. Dr. LeBoff has research support from Novartis., owns stock in Amgen, and has served on Roundtable discussions for Proctor and Gamble and Eli Lilly. All other authors have no conflicts of interest.
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