Bone Abstracts

Individuals with Down syndrome (DS) have a number of phenotypic features, including a short stature. It has been reported that people with DS have lower areal BMD than the general population, but this may be a biased result due to the smaller size of the skeleton, and it is unclear if individuals with DS have fragile bones. Thus, the objective of this study was to explore the skeleton of DS using two techniques, TBS and calcaneal ultrasound, which are not influenced by bone size.

We included 76 persons with Down syndrome and 77 age- and sex-matched controls in the study. The quality of bone was assessed by calcaneal ultrasonography with a Sahara device (Hologic Waltham, MA). TBS was calculated from DXA scans obtained with a Hologic QDR 4500 densitometer.

The average age was 33 years (18–34). 53% were men. The parameters measured by calcaneal ultrasonography were better in people with DS than in control (QUI: 108 vs 93, P=0.001; BUA: 79 vs 70 dB/MHz, P=0.048 and SOS 1578 vs 1549 m/s, P=2.1×10⁻⁵). In the analysis stratified by sex, we found that these parameters also were higher in women with DS than in control women, while in men the differences were only significant for SOS (Table 1). TBS was similar in SD and controls (1456 vs 1474, P=0.19). In the sex-stratified analysis, differences were not found in men (1455 vs 1464, P=0.68), nor in women (1458 vs 1485, P=0.13), with more than 90% individuals having normal TBS in either group.

In conclusion, despite previous reports showing a low areal BMD in DS, this study shows that individuals with DS have a normal skeletal quality at the central and peripheral regions, as assessed by TBS and calcaneal ultrasound.