Colles' fracture and bone density of the ultradistal radius

To determine whether Colles' fracture, generally considered a manifestation of postmenopausal osteoporosis, is associated with a decrease in bone density at the site of fracture, we measured bone mineral density of the ultradistal radius (UDR‐BMD) by single‐photon absorptiometry with computer‐assisted image processing. In 119 normal women (ages 22–92 years), UDR‐BMD decreased by 17% between ages 30 and 75 years. From UDR‐BMD measurements in these normal women and in 40 women (ages 53–80 years) with Colles' fracture alone, a population‐based analysis was made to estimate fracture risk at different values of UDR‐BMD. Colles' fracture was uncommon at UDR‐BMD > 0.40 g/cm² (the “fracture threshold”). As bone density decreased below this level, fractures became more frequent (a “gradient of risk”).