Change in Quantitative Ultrasound-assessed Speed of Sound as a Function of Age in Women and Men and Association With the Use of Antiresorptive Agents: The Canadian Multicentre Osteoporosis Study.

INTRODUCTION

Five-year changes in multisite quantitative ultrasound-assessed speed of sound (SOS in m/s) were studied in a cohort of women and men. The impacts of antiresorptive therapies and menopausal status on SOS were also assessed.

METHODOLOGY

Two SOS assessments, clinical assessments, and comprehensive questionnaires were completed 5 years apart on 509 women and 211 men. Age at first assessment was grouped into: <40 yr, 40-49 yr, 50-59 yr, 60-69 yr, 70-79 yr and 80+ yr. Mean rate of change in SOS at the distal radius and tibia were calculated for each age grouping by sex. SOS changes were stratified by antiresorptive use (yes, no) or menopausal status (premenopausal, postmenopausal, or bilateral oophorectomy).

RESULTS

Mean losses in SOS occurred over the 5 years in almost all age groupings. In women, mean losses in SOS for the <40 yr, 40-49 yr, 50-59 yr, 60-69 yr, 70-79 yr, and 80+ yr age groupings were -59, -83, -107, -92, -80 and -66 (p = 0.30; differences among age groupings) at the radius and -18, -16, -54, -1, -9 and 31 at the tibia (p < 0.05), respectively. In men, mean SOS losses were -101, -56, -69, -67, -83 and -127 at the radius (p = 0.61) and -46, -61, 0, -35, -29, and -26 at the tibia (p = 0.23). At the tibia, women prescribed antiresorptives had a mean increase in SOS (8.6 m/s) whereas untreated participants had a mean loss (-23.0; p < 0.001); there was no significant impact at the distal radius. There were no significant differences in change in SOS among menopausal groups (p > 0.26).

CONCLUSIONS

Mean SOS generally declined over 5 years in all age groupings of both sexes. The consistent mean losses in SOS over the age spans investigated are coincident with increasing fracture risk. Women on antiresorptive therapy had increased mean SOS over the 5-year assessment period at the tibia, whereas untreated women had mean losses in SOS.