Bone Abstracts

The aim of the study is to evaluate, across time, if a bone microarchitectural texture modification exists or not and to evaluate its associations with other bone and body composition parameters.

16 Spanish children suffering from DMD with a mean age 9.7±3.0 years and height and weight z-score of −0.76 and 0.16 SD were included in the study. Spine DXA scans and body composition scans were obtained using a GE Lunar Prodigy at baseline, 12 and 24 months of follow-up. Lumbar spine TBS was determined using Med-Imaps custom software to calculate raw values that were subsequently adjusted for tissue thickness based on a normative population of healthy Spanish boys and girls (n=4127). z-score TBS were evaluated using the same normative population. Variations of mean BMD and TBS during the follow-up were express in SD. z-scores variations of BMD, TBS, height and weight were also assessed

At baseline, BMD and TBS z-scores were −1.1SD and −0.2 S.D. respectively. Both TBS and BMD increased significantly during the follow-up with more marked increase for TBS as express in S.D.. A weak correlation between TBS and BMD variations has been observed (r=0.51). BMD and TBS z-score decreased along the follow-up as well as height and weight. This z-score decreases seems to be more marked on TBS (Δz-score=−0.78 S.D.), Height (Δz-score=−1.04 S.D.) and Weight (Δz-score=−1.39 S.D.) than on Spine BMD (Δz-score=−0.34 S.D.) after 24 months of follow-up. At baseline and 12 months, TBS was associated positively with total fat mass (r²=0.46, P=0.01 and r²=0.64, P<0.001) while lean mass, BMD at spine, age, BMI, height were excluded from the model. No association was calculated at 24 months due to a small number of patients.

As expected, both BMD and TBS increase during growth with a weak correlation between BMD and TBS changes (r²=26%). Although these physiological increases, these values remained below normal values for age. Interestingly, TBS seemed to be associated with the total fat mass while BMD was not. These results suggests that a bone texture impairment exists in DMD and that this impairment varies with growth. Further studies are needed to confirm these preliminary results.

Disclosure: Renaud Winzenrieth is senior scientist at Med-Imaps.