Inappropriate reference range for peak bone mineral density in dual-energy X-ray absorptiometry: implications for the interpretation of T-scores.
An inappropriate reference range for peak bone mineral density (BMD) may result in identification of an incorrect proportion of subjects with osteopenia and osteoporosis at dual-energy X-ray absorptiometry (DXA). In this study, we assessed the prevalence of low BMD in Turkish young adults with respect to local population reference range T-scores and the US reference range T-scores. The BMD values of lumbar spine (L1-L4) and proximal femur (femoral neck, intertrochanter, trochanter, Ward's triangle and total) were measured by DXA in 323 healthy young adults (171 women, 152 men) aged 19-25 years. The World Health Organization criteria for the diagnosis of osteopenia (-2.5 < T-score < -1) and osteoporosis (T-score < or = -2.5) were applied. In women, the means of the US reference range T-scores were significantly lower than zero at the spine and proximal femoral sites (p < 0.0001). In men, the means of the US reference range T-scores were significantly lower than zero at the spine, femoral neck, intertrochanter, total femur (p < 0.0001) and trochanter (p < 0.05), but not at Ward's triangle (p = 0.92). When the diagnoses were based on local population reference range T-scores instead of the US reference range T-scores, the prevalence of low BMD (T-score < -1) in women fell from 50.3% to 14.0% at the lumbar spine and from 60.8% to 14.6% at the femoral neck, and in men from 42.8% to 15.8% at the lumbar spine and from 30.9% to 17.1% at the femoral neck. Our data suggest that individual populations should use their own reference range T-scores to avoid misdiagnoses of osteopenia and osteoporosis by DXA.
Gürlek
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A
Department of Medicine, Division of Endocrinology, Hacettepe University School of Medicine, Ankara, Turkey. agurlek@hacettepe.edu.tr
Bayraktar
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M
Ariyürek
M
M
D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density; D005260:Female; D006801:Humans; D008297:Male; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000208:ethnology / Q000503:physiopathology*; D012016:Reference Values; D014421:Turkey; D014481:United States