Review of 3,530 referrals for bone density measurements of spine and femur: Evidence that radiographic osteopenia predicts low bone mass

PURPOSE: To determine the relationship between bone mineral density (BMD) measurements and the initial reason for referral to a BMD screening service. MATERIALS AND METHODS: Referral letters for 3,479 of the 3,530 women referred for BMD screening were classified according to the indication for screening. Mean age-matched standard deviation scores (Z scores) were derived for each of the 10 most common indications. Mean BMD between each group was compared with the age-matched value from the local normal range by means of a one-sample Student t test. Mean young normal standard deviation scores (T scores) were derived, and the percentages of women with osteopenia or osteoporosis from each referral group were calculated on the basis of the World Health Organization criteria. RESULTS: The most common reason for referral was to aid in a decision regarding hormone replacement therapy (n = 700). The highest proportion of women with osteoporosis in any group was in the radiographic osteopenia group (n = 269). CONCLUSION: Radiographic evidence of osteopenia is a strong predictor of osteoporosis. Screening for osteopenia appears justified in this and other high-risk groups and those seeking a rationale for preventive therapy.