Predicting clinical discordance of bone mineral density

To identify clinical and lifestyle factors that may predict clinical discordance of bone mineral density (BMD) in otherwise healthy perimenopausal and postmenopausal women referred for bone densitometry.

Data from 304 white women referred for bone densitometry were retrospectively reviewed in order to determine predictors of BMD status at the lumbar spine, femoral neck, and distal radius. In addition, a cross-validation study in a further independent sample of 50 patients was undertaken. Dual-energy x-ray absorptiometry of all three sites was performed, and T-scores were determined with use of standard criteria established by the World Health Organization. Covariables including age, postmenopausal status, years since menopause, use of alcohol and cigarettes, family history of osteoporosis, exercise, height, weight, and body mass index were analyzed by canonical discriminant functions.

Seventy-six patients (25%) had normal BMD at all three sites (group A); 55 patients (18%) had osteopenia or osteoporosis at all sites (group B); and 173 patients (57%) showed regional discordance of BMD (group C). Menopausal status, years since menopause, use of alcohol and cigarettes, exercise levels, and weight allowed distinct separation of these three groups by using the plot of one canonical discriminant function against the other. When tested, this method of assignment correctly predicted the regional BMD status in 38 of 50 women (76%) in the independent sample.

Thus, the combination of certain clinical and lifestyle factors may be helpful in predicting variations in the clinical classification of BMD in an ambulatory healthy perimenopausal or postmenopausal woman.