Calcaneal ultrasound attenuation in an elderly population: Measurement position and relationships with body size and past fractures

This study demonstrates the relationship between past fracture, body size a nd broadband ultrasound attenuation (BUA) and investigates two sites of BUA measurement in a representative elderly population of men and women (n = 2 106). We measured BUA at a fixed position and at a consistent anatomic posi tion within the calcaneus. We found fixed BUA was less closely correlated w ith stature and age than anatomic BUA. Both correlations were substantially weaker in men than in women. Mean BUA was significantly lower in women wit h a past fracture compared with nonfracturers (fixed BUA 63.3 vs 69.4 dB/MH z, p = 0.0004; anatomic BUA 77.6 vs 81.7 dB/MHz, p = 0.013). However, in wo men, the fixed BUA was better than the anatomic BUA at discriminating betwe en fracturers and nonfracturers (OR 1.38/SD (95% CI 1.12-1.68) and OR 1.22/ SD (0.99-1.52), respectively) when adjusted for body size and age. There wa s no significant difference in either BUA in men with or without a past fra cture. In conclusion, currently the fixed position for BUA measurement is p referable and, whilst we have demonstrated that it is possible to locate an anatomically consistent point in the calcaneus, the position chosen by thi s study did not provide a measurement with more discriminatory capability t han the fixed position. In women, BUA behaves similarly to bone mineral den sity in relation to stature and in its strength of association with past fr acture, while the lack of association in men may reflect differing contribu tions by bone strength to fracture risk in the sexes.