Examining the load-to-strength ratio helps explain increased fracture risk in both low-weight and obese women, according to a study of 65 women with anorexia nervosa, 45 controls, and 66 obese women. Researchers found:

• Women with anorexia nervosa had lower integral volumetric bone mineral density (Int.vBMD) than both obese women and controls, who had similar Int.vBMDs.

• Vertebral loads were highest in obesity and lowest in anorexia nervosa for standing, holding, and lifting, but were highest in anorexia nervosa for bending.

• Obese women had highest fracture risk for standing and lifting; women with anorexia nervosa had highest fracture risk for bending.

• Both obese women and women with anorexia nervosa had higher fracture risk for holding than controls.

• Int.vBND and estimated vertebral strength were associated positively with lean mass in all groups combines and negatively associated with visceral adipose tissue in obese women.

Citation: Bachmann KN, Bruno AG, Bredella MA, et al. Vertebral strength and estimated fracture risk across the BMI spectrum in women. [Published online ahead of print August 31, 2015]. J Bone Miner Res. doi: 10.1102/jbmr.2697.