Influence of soft tissue body composition on bone mass and metabolism.

Total body bone mineral (TBBM), lean body mass (LBM), and fat mass (FM) were measured by dual photon 153Gd absorptiometry in four female groups: (a) 27 patients with hip fracture; (b) 40 patients with spinal crush fracture; (c) 17 patients with osteoarthrosis, and (d) 26 healthy postmenopausal women. TBBM was significantly decreased in the two osteoporotic groups. The FM tended to be smaller in the two osteoporotic groups and larger in the osteoarthrotic group compared to the control group, whereas, LBM was virtually equal in all four groups. A significant negative correlation (p less than 0.01) was found between fasting urinary calcium corrected for creatinine and FM, whereas no relation between plasma bone Gla protein and FM could be demonstrated. We conclude that an increased fat mass after the menopause decreases bone resorption without a corresponding decrease in bone formation.