Quantitative ultrasound of the calcaneus in greek women: normative data are different from the manufacturers normal range.
Quantitative ultrasound (QUS) is considered a useful method in evaluating bone status. The aim of the present study was to establish the reference data for the QUS measurements of the calcaneus in a Greek population. We measured a QUS parameter, stiffness index (SI), at the right calcaneus in 1500 women using the Achilles express Ultrasonometer (GE Lunar, Madison, WI). Participants were divided into 7 groups according to their age with a 10-yr span in each group. A progressive decline was found in the SI values after the age of 39 yr in the current study. When the SI values were compared between the age groups, high statistically significant differences were obvious, especially between 20-29 and 50- to 59-yr age groups and 60-69 and 70- to 79-yr age groups (p < 0.0005). Additionally, in the Greek normal range (GNR), the SI values of those aged 60-69 and 70-79 yr were significantly higher (81.84+/-16.14 and 77.45+/-17.65, respectively) than those in the manufacturers normal range (MNR; 75.84+/-16.14 and 69.10+/-17.65, p < 0.005, respectively). Using the manufacturers values, significantly fewer women were classified as normal (48% vs 67.3%), although those with T-score < or =-2.5 were more (15.7%) compared with our Greek value (1.5%), and classification of subjects into risk-of-fracture categories was significantly different (kappa: 0.459, 66.2%, p < 0.0005). Multiple regression analysis showed that weight was the most significant predictor for SI in the age groups 30-39 (beta = 0.280, p < 0.05), 40-49, 60-69, and 70-79 yr (beta = 0.185, p < 0.005; beta = 0.329, p < 0.0005; beta = 0.494, p<0.0005, respectively). Using conventional categories of risk, we report a different classification of our subjects from those proposed by the manufacturer, supporting the concept that data specific to the Greek population are necessary.