Fat mass and skeletal muscle mass in hip-fracture women: a cross-sectional study

To investigate the association between appendicular lean mass (aLM) and age, fat mass (FM), serum levels of Vitamin D, parathyroid hormone, three parameters of the protein nutritional status (total lymphocyte count, serum albumin, and insulin-like growth factor I), levels of independence in activities of daily living (assessed by using Barthel index scores), type both of hip fracture and surgical operation, number of medications in use, and number of concomitant diseases in hip-fracture women.

We investigated 299 of 327 hip-fracture women admitted consecutively to a rehabilitation hospital. Soft tissue body composition was assessed by dual-energy X-ray absorptiometry, 22.1+/-7.5 (mean+/-S.D.) days after fracture occurrence. Appendicular LM was calculated as the sum of LM in arms and legs. Because metal implants (prostheses and nails) affect the regional assessment of body composition, aLM was corrected by substituting LM in unfractured leg for LM in fractured leg: corrected aLM=(LM in unfractured leg x 2)+LM in arms. We divided corrected aLM by height squared (aLM/ht(2)), to adjust it for body size.

Four variables were significantly correlated with corrected aLM: age, height, FM, and Barthel index score. FM was the only variable significantly correlated with aLM/ht(2) (r=0.492; p<0.001). This significant correlation was not affected after adjustment for age and Barthel index score.

FM measured after hip fracture was significantly associated with aLM/ht(2) in women.