This investigation prospectively described the change in speed of sound (SOS in m/s), as measured by multisite quantitative ultrasound (mQUS), over a five-year period in randomly selected community-based individuals from the Canadian Multicentre Osteoporosis Study (CaMOS). SOS was assessed by Beam-Med Omnisense mQUS at the distal radius (DR) and tibia (TIB). Participants receiving antiresorptive therapy or glucocorticoid therapy were excluded. Participants were grouped by age (<40, 40-49, 50-59, 60-69, 70-79, and 80+ years) to assess age-related differences in the rate of change in SOS. Differences among groups were assessed by analysis of variance. Pearson product-moment correlations were performed between change in SOS and baseline SOS, age, height and mass. In this subset of CaMOS data, there were 321 women (30-87.7 years old) and 201 men (30.2-88.8 years old). The mean (standard deviation) loss of SOS over the five-year follow-up was 94.5 (113.9) and 74.6 (114.8) m/s at the DR and 18.7 (116.3) and 28.1 (100.0) m/s at the TIB in women and men, respectively (between sexes differences: DR p=0.06; TIB p=0.35). For both women and men there were no significant differences in the rate of loss among age groupings, although there was a trend for women to have a greater rate of change at the 50-59 yr group, coincident with the average age of menopause. While there were small, yet significant (p<0.05), correlations between the rate of change in TIB SOS and height (r=-0.10) and mass (r=0.11), the strongest predictor of rate of change in SOS was baseline SOS: DR r=-0.45 and TIB r=-0.47 (both p<0.001). In conclusion, consistent losses in SOS were observed in all age groups over a five-year follow-up. As the strongest predictor of five-year SOS loss was low baseline SOS, individuals with low SOS may have the greatest risk for fracture.
Disclosure: The authors declared no competing interests.