Ultrasound measurements at the calcaneus in men: differences between healthy and fractured persons and the influence of age and anthropometric features on ultrasound parameters.

The aim of this cross-sectional study was to assess the ability of quantitative ultrasound at the calcaneus to discriminate between fractured and unfractured men, fracture probability, and the relationship of ultrasonic parameters to age and body size. The study included 224 men (age range 36-86 years) with no history of diseases or therapy affecting bone metabolism. The subjects were divided into two groups (unfractured, n = 148; fractured, n = 76) matched for age and body size. Bone status was assessed by ultrasound measurements at the calcaneus. Long-term in vitro CV% values were 0.88% for speed of sound (SOS) and 0.54% for broadband ultrasound attenuation (BUA). In vivo CV% values were 0.33% for SOS and 2.48% for BUA, while sCV% values were 4.66% and 6.58%, respectively. The following SOS/BUA values were obtained: in unfractured men, SOS = 1517.5 +/- 35.3 m/s and BUA = 114.0 +/- 13.3 dB/MHz; in fractured men, SOS = 1492.6 +/- 24.6 m/s and BUA = 106.1 +/- 11.6 dB/MHz. The differences were significant (p<0.0001). The odds ratio for BUA for all fractures was 1.05 (95% CI, 0.03-2.07) and for SOS 2.13 (95% CI, 0.77-3.49). Only the age-related decrease in SOS in unfractured men was significant (r = -0.17, p<0.05). In fractured men, weight and body mass index (BMI) were found to correlate significantly with BUA (r = 0.31, p = 0.007, r = 0.31, p = 0.007, respectively). The areas under receiver operating characteristics (ROC) curves were 0.706 for SOS and 0.665 for BUA. Ultrasound measurements at the calcaneus thus enable discrimination between fractured and healthy males. Different patterns of the relationship between age and body size in the two groups suggest the presence of other, unknown factors affecting bone status. Their identification requires further prospective studies.