Department of Growth and Pediatric Endocrinology, Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune, India.
Department of Growth and Pediatric Endocrinology, Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune, India.
Bone. 2021 Feb;143:115730. doi: 10.1016/j.bone.2020.115730. Epub 2020 Oct 31.
Children with beta thalassemia major (BTM) are known to have reduced bone mass which increases incidence of non-traumatic fractures. Few studies have assessed prevalence of fractures and bone health in underprivileged children with BTM. Our objectives were to 1) determine prevalence of fractures in underprivileged Indian children with BTM, 2) assess size corrected bone density and bone geometry using Dual x-ray absorptiometry (DXA) and peripheral quantitative computerized tomography (pQCT) in these children and healthy controls 3) determine predictors of fractures in children with BTM 4) compare differences in bone density between children with BMT with and without fractures. Bone mineral content and areal bone mineral density (aBMD) of lumbar spine and whole body and vertebral fracture assessment (VFA) was performed by DXA in 334 children (3-18 years, 167 BTM + 167 controls). Volumetric BMD (vBMD) and bone geometry were assessed by pQCT (subset, 70 BTM, 70 healthy) at distal radius. Children with BTM had higher prevalence of vertebral and long bone fractures (p < 0.05). DXA aBMD was lower in children with BTM (p < 0.05), whereas, lumbar spine bone mineral apparent density (LSBMAD) was higher (p > 0.05). Children with BTM had lower total distal radial vBMD, cortical vBMD and strength strain index (SSI) at 66% site whereas, distal radial trabecular vBMD at 4% was higher (p < 0.05). On height adjustment, children with BTM had lower muscle area and cortical thickness and higher marrow area (p < 0.05) at 66% site. Age, body size, total body less head (TBLH) aBMD and strength strain index (SSI) were important predictors of fractures in children with BTM. Thus, children with BTM had higher prevalence of non-traumatic fractures. Despite lower areal and volumetric densities, they had higher LSBMAD and trabecular densities which may be attributed to erythroid hyperplasia and iron deposition due to inadequate transfusion and chelation. As LSBMAD is raised in these children, it is unlikely to identify BTM subjects at risk of fracture; VFA thus maybe useful in identifying asymptomatic vertebral fractures.
患有重型β地中海贫血症（BTM）的儿童骨质减少，这增加了非外伤性骨折的发生率。很少有研究评估贫困儿童 BTM 骨折和骨骼健康的患病率。我们的目的是：1）确定贫困印度儿童 BTM 骨折的患病率，2）使用双能 X 射线吸收法（DXA）和外周定量计算机断层扫描（pQCT）评估这些儿童和健康对照者的骨密度和骨几何结构，3）确定 BTM 患儿骨折的预测因素，4）比较伴或不伴骨折的 BMT 患儿的骨密度差异。通过 DXA 对 334 名儿童（3-18 岁，167 名 BTM + 167 名对照者）的腰椎、全身体和椎体骨折评估（VFA）进行骨矿物质含量和面积骨矿物质密度（aBMD）检测。通过 pQCT（子集中的 70 名 BTM 和 70 名健康儿童）对桡骨远端的体积骨密度（vBMD）和骨几何结构进行评估。患有 BTM 的儿童的椎体和长骨骨折发生率更高（p<0.05）。患有 BTM 的儿童的 DXA aBMD 较低（p<0.05），而腰椎骨矿物质表观密度（LSBMAD）较高（p>0.05）。66%部位的 BTM 患儿总桡骨远端 vBMD、皮质 vBMD 和强度应变指数（SSI）较低，而 4%部位的桡骨远端小梁 vBMD 较高（p<0.05）。在身高调整后，66%部位的 BTM 患儿的肌肉面积和皮质厚度较低，骨髓面积较大（p<0.05）。年龄、体型、全身体积减去头部（TBLH）aBMD 和强度应变指数（SSI）是 BTM 患儿骨折的重要预测因素。因此，患有 BTM 的儿童非外伤性骨折发生率更高。尽管面积和体积密度较低，但他们的 LSBMAD 和小梁密度较高，这可能归因于由于输血和螯合不足而导致的红系增生和铁沉积。由于这些儿童的 LSBMAD 升高，因此不太可能识别出有骨折风险的 BTM 患者；因此，VFA 可能有助于识别无症状的椎体骨折。
