Accurate assessment of individual fracture risk requires measurement of bone mass (density). Another strong risk factor for identifying women or men who will develop fractures in the near future is the presence of previous (spine and nonspine) fractures. However, the occurrence of a low-trauma fracture almost anywhere in the skeleton is indicative of a more advanced stage of disease and is associated with a substantial, further increase in fracture risk, independent of bone mass. Thus, prevention of the first fracture should receive priority. In a clinical setting, initial assessment of bone mass can be combined with other, known risk factors and projected over the patient's remaining life expectancy, to estimate future, cumulative fracture probability. Estimates such as "remaining lifetime fracture probability" can also approximate the impact and cost-effectiveness of treatment, allowing for more objective and rational therapeutic planning for individual patients.