Dual x ray absorptiometry is the reference method to measure bone mineral density (BMD) accurately and reproducibly. The World Health Organization defines osteoporosis on the basis of the T score (which is the difference between the measured BMD and the mean value of young adults, expressed in standard deviations for a normative population of the same ethnicity).¹ Although the BMD at different anatomical regions is correlated, the agreement between sites is low when it comes to classifying individual subjects as having osteoporosis.² Various studies have analysed the prevalence and effect of T score discordance on the management of osteoporosis.^3–,⁷ However, most of these studies did not evaluate risk factors for this phenomenon. …