[Body weight and bone/calcium metabolism. Body mass index, bone mineral density, and fracture.]

High body weight and high BMI has long been thought to protect against osteoporosis and fragility fractures. However, recent studies indicate that obese individuals fracture risk in some body sites increased with obesity, although it is consistent that obesity remains a protective factor for hip fracture. The association between BMI and fracture risk is complex, differs among fracture sites, and is modified by BMD. FRAX® tool including weight and height is effective to predict fracture even among obesity persons.