Bone mass measurement, fracture risk, and screening for osteoporosis.

There is a positive relationship between bone mass and resistance to breaking. Measurements of the spine made by quantitative computed tomography (QCT) and dual photon absorptiometry (DPA) appear to allow a determination of the risk of vertebral compression fracture, although some important confirmatory studies remain to be done. Measurements made in the extremities generally do not allow prediction of vertebral fracture risk. Prediction of hip fracture risk is difficult because of the complex geometry of the femur. The few data which are available suggest that DPA may be useful to predict the risk of femoral neck fracture. If these data can be confirmed, cost-benefit analysis indicates that mass screening for osteoporosis may be a viable strategy. Physicians and patients using bone mass measurement techniques should be aware that these tests can be misleading, and that scrupulous attention to detail is required. Close supervision of the tests by a physician is necessary to ensure that meaningful data are obtained.