Objectives Boys with Duchenne Muscular Dystrophy (DMD) are at increased risk for compromised bone health, manifesting as low-impact trauma long bone fractures and vertebral compression fractures. Methods In a prospective observational study, we studied bone health parameters in North Indian boys with DMD. We consecutively enrolled ambulatory boys with DMD on glucocorticoid therapy. Bone health was evaluated with X-ray spine, Dual-energy X-ray absorptiometry (DXA), serum calcium, vitamin D3 (25[OH]D), 1,25-dihyroxyvitamin D3 (1,25[OH] 2 D 3 ), serum osteocalcin, osteopontin, and N terminal telopeptide of type 1 collagen (Ntx) levels. Results A total of 76 boys with DMD were enrolled. The median age was 8.5 (interquartile range [IQR] 7.04–10.77) years. Among these, seven (9.2%) boys had long bone fractures, and four (5.3%) had vertebral compression fractures. Fifty-four (71%) boys underwent DXA scan, and among these 31 (57%) had low bone mineral density (BMD, ≤−2 z-score) at the lumbar spine. The mean BMD z-score at the lumbar spine was −2.3 (95% confidence interval [CI] = −1.8, −2.8), and at the femoral neck was −2.5 (95% CI = −2, −2.9). 25(OH)D levels were deficient in 68 (89.5%, n=76) boys, and 1,25(OH) 2 D 3 levels were deficient in all. Mean serum osteocalcin levels were 0.68 ± 0.38 ng/mL (n=54), serum osteopontin levels were 8.6 ± 4.6 pg/mL (n=54) and serum Ntx levels were 891 ± 476 nmol/L (n=54). Boys with low BMD received glucocorticoids for longer duration, in comparison to those with normal BMD (median, IQR [16.9 (6–34) months vs. 7.8 (4.8–13.4) months]; p=0.04). Conclusions Bone health is compromised in North Indian boys with DMD. BMD at the lumbar spine is reduced in more than half of boys with DMD and nearly all had vitamin D deficiency on regular vitamin D supplements. Longer duration of glucocorticoid therapy is a risk factor for low BMD in our cohort.

中文翻译：

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杜氏肌营养不良症男孩的骨密度和骨骼健康改变：一项前瞻性观察研究

目的 患有杜氏肌营养不良症 (DMD) 的男孩骨骼健康受损的风险增加，表现为低冲击外伤性长骨骨折和椎体压缩性骨折。方法 在一项前瞻性观察研究中，我们研究了北印度 DMD 男孩的骨骼健康参数。我们连续招募了接受糖皮质激素治疗的 DMD 门诊男孩。骨骼健康通过 X 射线脊柱、双能 X 射线吸收测定法 (DXA)、血清钙、维生素 D3 (25[OH]D)、1,25-二羟基维生素 D3 (1,25[OH] 2 D 3 )、血清骨钙素、骨桥蛋白和 1 型胶原 (Ntx) 水平的 N 末端端肽。结果共纳入76名DMD男孩。中位年龄为 8.5（四分位距 [IQR] 7.04-10.77）岁。其中，七名 (9.2%) 男孩患有长骨骨折，四名 (5. 3%) 有椎体压缩性骨折。54 名 (71%) 男孩接受了 DXA 扫描，其中 31 名 (57%) 的腰椎骨密度（BMD，≤-2 z 值）较低。腰椎的平均 BMD z 值为 -2.3（95% 置信区间 [CI] = -1.8, -2.8），股骨颈的平均 BMD z 值为 -2.5（95% CI = -2, -2.9）。68 名（89.5%，n=76）男孩的 25(OH)D 水平不足，所有男孩都缺乏 1,25(OH) 2 D 3 水平。平均血清骨钙素水平为 0.68 ± 0.38 ng/mL (n=54)，血清骨桥蛋白水平为 8.6 ± 4.6 pg/mL (n=54)，血清 Ntx 水平为 891 ± 476 nmol/L (n=54)。与 BMD 正常的男孩相比，低 BMD 的男孩接受糖皮质激素治疗的时间更长（中位数，IQR [16.9 (6-34) 个月 vs. 7.8 (4.8-13.4) 个月]；p=0.04）。结论 患有 DMD 的北印度男孩的骨骼健康受到损害。超过一半的 DMD 男孩的腰椎 BMD 降低，并且几乎所有人都因定期补充维生素 D 而缺乏维生素 D。在我们的队列中，较长时间的糖皮质激素治疗是低 BMD 的危险因素。