Bone mineral density reference range in Estonia: a comparison with the standard database (NHANES III)

Dual-energy X-ray absorptiometry (DXA) is accepted as a standard for diagnosing osteoporosis. Several databases are available for T-score calculation worldwide. Our aim was to compare hip bone mineral density (BMD) in young Estonian adults with the mean BMD in the National Health and Nutrition Examination Survey (NHANES) femur database and to compare the performance of these 2 databases. A population sample of 304 subjects was analyzed with a Lunar DPX-IQ DXA machine (GE Lunar Co., Madison, WI). Seventy-seven healthy young individuals were selected based on their age (25-39 yr). Their femur neck, trochanter, and total hip mean standardized BMD was compared with the corresponding data from the NHANES III database. Diagnostic agreement was assessed in a population sample of adults and in a clinical convenience sample from the densitometry unit. The BMD in the proximal femur in healthy young Estonian adults did not differ from the mean BMD in the NHANES subjects (p > 0.05). Differences in diagnosing osteoporosis and osteopenia are present if the Estonian reference database is used instead of the US standard database. Prospective studies with fracture data for assessing the predictive capability of these reference databases and the additional benefit of adding the FRAX (World Health Organization Collaborating Centre for Metabolic Bone Diseases, University of Sheffield, UK) tool to fracture prediction and osteoporosis diagnosis are needed in Estonia.