Bone Abstracts

Peak bone mass, typically reached in the third decade, is the highest bone mass acquired after completion of normal growth. Attaining a higher young adult bone mass may contribute to a lower risk of fragility fractures later in life. Few studies have specifically investigated quantitative ultrasound (QUS) in relation to peak bone mass in young adult women. The study objectives were to describe normative QUS values for 25 year old women and how extremes of body weight relate to QUS.

The QUS variables speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) were measured at the calcaneous in the population based PEAK-25 cohort (n=1061; age 25.5±0.2). Written informed consent was obtained from all participants. Based on the QUS manufacturer supplied reference values, young adult % values (YA%) were calculated. Analyses were performed (i) in the whole cohort and (ii) comparing women in the lowest and highest octiles for weight or body mass index (BMI).

Compared to the reference population, young adult SOS values in the PEAK-25 cohort were higher (108±18%). SOS relates to BMD and mirrors the previous finding of comparatively high BMD in the cohort. BUA values, which relate to bone complexity, were lower (90±14%). Body weight or BMI did not correlate with SOS. In the cohort overall correlations between BUA, weight and BMI were Pearson’s r=0.261; r=0.197 respectively; P<0.001). In the low-weight group, r-coefficients were higher (r=0.313; r=0.268; P<0.05). In contrast, in the high-weight group correlation between BUA, weight and BMI tended to be small, negative and non-significant.

In conclusion, in these 25-year old women, a comparatively high peak bone mass appears to be offset by less complex bone structure. This may have serious implications for osteoporosis assessment and future fracture risk.