Fracture Risk and Areal Bone Mineral Density in Adolescent Females with Anorexia Nervosa

Objective: To (i) compare fracture prevalence in adolescent females with anorexia nervosa (AN) versus normal-weight controls and (ii) examine whether reductions in areal bone mineral density (aBMD) predict fracture risk in females with AN. Method: Four-hundred eighteen females (310 with active AN and 108 normal-weight controls) 12- to 22-years-old were studied cross-sectionally. Lifetime fracture history was recorded by a physician during participant interviews. Body composition and aBMD measurements of the whole body, whole body less head, lumbar spine, and hip were assessed by dual-energy X-ray absorptiometry, and bone mineral apparent density (BMAD) was calculated for the lumbar spine. Results: Participants with AN and normal-weight controls did not differ for chronological age, sexual maturity, or height. The lifetime prevalence of prior fracture was 59.8% higher in those with AN as compared to controls (31.0% vs. 19.4%, p = 0.02), and the fracture incidence rate peaked in our cohort after the diagnosis of AN. Lower aBMD and lumbar BMAD were not associated with a higher prevalence of fracture in the AN or control group on univariate or multi-variate analyses. Compared to controls, fracture prevalence was significantly higher in the subgroup of girls with AN who had normal aBMD or only modest reductions of aBMD (Z-scores > -1 or -1.5). Discussion: This is the first study to show that the risk of fracture during childhood and adolescence is significantly higher in patients with AN than in normal-weight controls. Fracture prevalence is increased in this cohort of participants with AN even without significant reductions in aBMD. (C) 2014 Wiley Periodicals, Inc.