Bone mass of the axial and the appendicular skeleton in women with Colles' fracture: its relation to physical activity.

The aim of this investigation was to elucidate whether Colles' fractures in middle-aged women were indicative of generalized bone loss (osteopenia) and whether bone mass of the axial and the appendicular skeleton was related to the extent of daily physical activity. Thirty-six patients (aged 50-73 years) with previous Colles' fracture were studied. The median time elapse after the injury was 18 months (range 9-20.5 months). Bone mineral content of the 2nd, 3rd, and 4th lumbar vertebrae (lumbar BMC) and both distal forearms (forearm BMC) were determined to dual-photon (153Gd) absorptiometry. The physical activity level was graded according to a standard interview and a bicycle ergometer test. Mean lumbar BMC was reduced by 9% compared to age-matched normal women (p less than 0.05), mean forearm BMC was reduced by 5% (NS). Twenty patients showed spinal osteopenia by either conventional radiography or absorptiometry (95% confidence limits 38-72%). The fracture-related bone loss from the forearms was most prominent when the fracture had occurred in the dominant forearm, suggesting that the loss of 'dominant' forearm activity per se results in bone loss. No relation between working capacity and forearm BMC was found. However, the working capacity was positively related to lumbar BMC (P less than 0.01), even if the common relationship to age was eliminated (P less than 0.05). The data suggest that the bone mass of the axial skeleton reflects the extent of daily physical activity. Patients with Colles' fractures represent an easily definable population which might benefit from prophylactic measures against vertebral bone loss and compression fractures. One of these could be physical exercise.