Analysis of volumetric BMD in people with Down syndrome using DXA-based 3D modeling.
We analyzed volumetric bone mineral density, by 3D analysis, in 76 people with Down syndrome and 76 controls. People with Down syndrome, particularly men, have a lower hip volumetric bone mineral density than the general population. Besides, volumetric bone mineral density declines more rapidly in Down syndrome.


INTRODUCTION
People with Down syndrome (DS) have a lower areal bone mineral density (aBMD) estimated by dual-energy X-ray absorptiometry (DXA). However, they have smaller-sized bones, which could influence the measurements. Therefore, our objective was to determine volumetric BMD in these patients.


MATERIALS AND METHODS
We included 76 outpatients with DS and 76 control healthy volunteers matched for age and sex distribution. Clinical data were obtained with a standardized interview and physical exam, including age, sex, height, weight, and body mass index (BMI). aBMD was measured by dual-energy X-ray at the femoral neck (FN) and total hip (TH). The 3D-SHAPER® software (version 2.8, Galgo Medical, Barcelona, Spain) was used to derive 3D analysis from participants' hip DXA scans.


RESULTS
DS femurs had a similar 3D geometry, compared with the femurs of controls. However, 3D analysis showed that participants with DS had smaller cortical thickness (1.84 mm ± 0.17 vs. 2.02 ± 0.20 mm; p < 0.0001), cortical vBMD (777 ± 49 mg/cm3 vs. 809 ± 43 mg/cm3; p < 0.0001), and cortical sBMD (143 ± 19 mg/cm2 vs. 164 ± 22 mg/cm2; p < 0.0001). After adjustment for age and BMI, all 3D measurements remained lower in DS than in controls. These differences were more marked in men than in women. vBMD decreased with age in controls and DS, but the decline was greater in DS for all 3D parameters.


CONCLUSION
People with DS, particularly men, have a lower hip vBMD than the general population. Besides, vBMD declines more rapidly in DS.
['García Hoyos|Marta|M|', 'Humbert|Ludovic|L|', 'Salmón|Zaida|Z|', 'Riancho|José A|JA|', 'Valero|Carmen|C|']
D015502:Absorptiometry, Photon D000328:Adult D015992:Body Mass Index D001835:Body Weight D015519:Bone Density D016022:Case-Control Studies D004314:Down Syndrome D005260:Female D005269:Femur D005272:Femur Neck D006801:Humans D008297:Male D013030:Spain D055815:Young Adult
Volumetric Down 3D modeling Bone mineral density Osteoporosis