Our results are also useful to help clarify some of the inconsistent results that have been shown with the SCORE. Since its development in 1998, the SCORE has been evaluated in several studies, with inconsistent results,20,32- 35 likely owing to differences in the sample populations. A CPR should be validated in a population similar to that in which it is meant to be used—in the case of a CPR that will be used as an osteoporosis screening tool in the general population of postmenopausal women, the CPR should ideally be tested in a sample that is representative of this population. Lydick et al20 described a sensitivity and specificity of 89% and 50%, respectively, in the development cohort (mean age, 61.5 years) and 91% and 40%, respectively, in the validation cohort (mean age, 63.1 years), using a T score of −2.0 or less at the femoral neck as the definition of osteoporosis. The development and validation cohorts had osteoporosis prevalences of 38% and 44%, respectively. However, when the SCORE was later applied to a sample of community-dwelling postmenopausal women in Rancho Bernardo, Calif (mean age, 72.5 years), with osteoporosis prevalence of 67% as defined by BMD T score of −2.0 or less at the femoral neck,32 the sensitivity was 98% and the specificity was only 12.5%. Cadarette et al33 applied the SCORE to a sample of 398 postmenopausal women participating in the large population-based Canadian Multicenter Osteoporosis Study. Those authors reported a sensitivity of 90% and a specificity of 32% in their population of postmenopausal women (mean age, 64.5 years) with an osteoporosis prevalence of 50% (using BMD T score of −2.0 or less at the femoral neck as the definition of osteoporosis). More recently, Cadarette et al38 applied the SCORE to an even larger (N = 2365) sample of the same study population (mean age, 66.4 years) and reported a sensitivity of 99.6% and a specificity of 17.9% (using BMD T score of −2.0 or less as the definition of osteoporosis, this sample had a prevalence of 25.4%; using a BMD T score of −2.5 or less, the prevalence was only 10%). Two other studies have also reported sensitivities and specificities for the SCORE; however, these sample populations consisted of postmenopausal women who were referred for BMD testing and thus were not representative of a true situation for which this tool would be used.34,35 These inconsistencies can best be explained by the spectrum of patients to whom the SCORE was applied. The Rancho Bernardo study was a sample of community-dwelling women; however, there must have been patient selection bias because the prevalence of osteoporosis was so high and the average age was 10 years older than those in the original study by Lydick et al.20 As patient age increases, the more likely the SCORE will produce false-positive results, because age is a major point contributor in the SCORE calculation, thus explaining why the specificity reported from the Rancho Bernardo study was so much lower than that reported by Lydick et al.20 The 2 studies by Cadarette et al33,38 nicely illustrate this point as well. The first study33 with 398 women had an average age similar to the cohorts studied by Lydick et al.20 However, in the larger study of 2365 women,38 the mean age was older and the specificity was lower. In our study, because the cohort was stratified by age, there was overrepresentation of the older women compared with that of the normal population, and therefore the mean age was 69.2 years. When the data were directly age adjusted, the sensitivity and specificity were 100% and 27%, respectively. It is difficult, however, to compare our results directly with those of the other studies because the BMD T score cutoff used to define osteoporosis is −2.0 or less in most of those studies, and we used the more conservative value of T score of −2.5 or less. In our study sample, the age-adjusted prevalence of osteoporosis as defined by BMD T score of −2.5 or less at the femoral neck was 25%, compared to a similar 22% figure for white women from the Third National Health and Nutrition Examination Survey data.44 The Third National Health and Nutrition Examination Survey reports only prevalence of osteoporosis (BMD T score of −2.5 or less) and osteopenia (BMD T score of −1 or less to −2.5); it does not report a prevalence for a BMD T score of −2.0 or less to compare with those of the other SCORE studies.