Reference data in a Swiss population -: Discordance in patient classification using T-scores among calcaneum, spine, and femur

For the detection of osteoporosis, a portable, inexpensive, nonirradiating technique of quantitative ultrasound (QUS) was developed. This study aimed at determining reference QUS values for a population of white Swiss women ages 18-90 yr and checking the adequacy of the World Health Organization classification of osteoporosis for QUS. Three hundred thirty-three women were measured at the nondominant calcaneus with the QUS Sahara and a subgroup of 215 on both sides. Women aged 20-35 (n = 78) were selected to form the QUS peak bone mass group (PBM). Twenty-nine women underwent an additional dual X-ray absorptiometry measurement, to validate the choice of the PBM group. Indeed, their spine and hip bone mineral density (BMD) T-scores did not differ from the DXA reference values used in the clinical routine. PBM values of the quantitative ultrasound index (QUI), broadband ultrasound attenuation, and speed of sound were 99.3 +/- 16.0% YA, 69.9 +/- 11.7 dB/MHz, and 1565.0 +/- 29.5 m/s, respectively. No significant differences were found between nondominant and dominant sides for QUI measurements. Since QUS parameters of the normal population, expressed as T-scores, start to decrease at a younger age than the femoral neck BMD assessed by DXA and its ability to discriminate osteoporotic fracture is equivalent to DXA, QUS Sahara could potentially be used to screen women at risk of osteoporosis.