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.

Salud ósea en el síndrome de Down / Bone health in Down syndrome

Las personas con síndrome de Down podrían tener un mayor riesgo de osteoporosis debido a un envejecimiento precoz, alteraciones en el desarrollo o la presencia de factores de riesgo como baja actividad física, menor exposición solar, elevada comorbilidad o el uso de tratamientos que afectan al metabolismo óseo. Además, tienen peculiaridades antropométricas y de composición corporal que podrían influir en su masa ósea. Los estudios en adultos vienen a decir que tienen una densidad mineral ósea en g/cm2 inferior a la de la población general, pero la mayoría no tienen en cuenta el menor tamaño de sus huesos, de tal manera que cuando se ajusta por el mismo (densidad mineral ósea volumétrica g/cm3), estas diferencias se reducen o desaparecen. Los estudios sobre niveles de 25(OH)D, parámetros de remodelación ósea o prevalencia de fracturas no son concluyentes (AU)

Patients with Down syndrome have a number of risk factors that theoretically could predispose them to osteoporosis, such as early aging, development disorders, reduced physical activity, limited sun exposure, frequent comorbidities and use of drug therapies which could affect bone metabolism. In addition, the bone mass of these people may be affected by their anthropometric and body composition peculiarities. In general terms, studies in adults with Down syndrome reported that these people have lower areal bone mineral density (g/cm2) than the general population. However, most of them have not taken the smaller bone size of people with Down syndrome into account. In fact, when body mineral density is adjusted by bone size and we obtain volumetric body mineral density (g/cm3), the difference between both populations disappears. On the other hand, although people with Down syndrome have risk factor of hypovitaminosis D, the results of studies regarding 25(OH)D in this population are not clear. Likewise, the studies about biochemical bone markers or the prevalence of fractures are not conclusive (AU)

Bone health in Down syndrome. / Salud ósea en el síndrome de Down.

Patients with Down syndrome have a number of risk factors that theoretically could predispose them to osteoporosis, such as early aging, development disorders, reduced physical activity, limited sun exposure, frequent comorbidities and use of drug therapies which could affect bone metabolism. In addition, the bone mass of these people may be affected by their anthropometric and body composition peculiarities. In general terms, studies in adults with Down syndrome reported that these people have lower areal bone mineral density (g/cm2) than the general population. However, most of them have not taken the smaller bone size of people with Down syndrome into account. In fact, when body mineral density is adjusted by bone size and we obtain volumetric body mineral density (g/cm3), the difference between both populations disappears. On the other hand, although people with Down syndrome have risk factor of hypovitaminosis D, the results of studies regarding 25(OH)D in this population are not clear. Likewise, the studies about biochemical bone markers or the prevalence of fractures are not conclusive.