Institute for Experimental Medical Research and KG Jebsen Center for Cardiac Research, University of Oslo and Oslo University Hospital, Ullevål, 0027, Oslo, Norway.
Bjørknes University College, Oslo, Norway.
Pediatr Rheumatol Online J. 2021 Apr 26;19(1):56. doi: 10.1186/s12969-021-00543-z.
Juvenile dermatomyositis (JDM) is the most common idiopathic inflammatory myopathy in children and adolescents. Both the disease and its treatment with glucocorticoids may negatively impact bone formation. In this study we compare BMD in patients (children/adolescence and adults) with long-standing JDM with matched controls; and in patients, explore how general/disease characteristics and bone turnover markers are associated with BMD.
JDM patients (n = 59) were examined median 16.8y (range 6.6-27.0y) after disease onset and compared with 59 age/sex-matched controls. Dual-energy X-ray absorptiometry (DXA) was used to measure BMD of the whole body and lumbar spine (spine) in all participants, and of ultra-distal radius, forearm and total hip in participants ≥20y only. Markers of bone turnover were analysed, and associations with outcomes explored.
Reduced BMD Z-scores (<-1SD) were found in 19 and 29% of patients and 7 and 9% of controls in whole body and spine, respectively (p-values < 0.05). BMD and BMD Z-scores for whole body and spine were lower in all patients and for < 20y compared with their respective controls. In participants ≥20y, only BMD and BMD Z-score of forearm were lower in the patients versus controls. In patients, BMD Z-scores for whole body and/or spine were found to correlate negatively with prednisolone use at follow-up (yes/no) (age < 20y), inflammatory markers (age ≥ 20y) and levels of interferon gamma-induced protein 10 (IP-10) (both age groups). In all patients, prednisolone use at follow-up (yes/no) and age ≥ 20y were independent correlates of lower BMD Z-scores for whole body and spine, respectively.
In long-term JDM, children have more impairment of BMD than adults in spine and whole-body. Associations with BMD were found for both prednisolone and inflammatory markers, and a novel association was discovered with the biomarker of JDM activity, IP-10.
幼年特发性皮肌炎（JDM）是儿童和青少年中最常见的特发性炎症性肌病。疾病本身及其糖皮质激素治疗都可能对骨形成产生负面影响。在这项研究中，我们比较了长期 JDM 患者（儿童/青少年和成人）与匹配对照者的骨密度；并在患者中，探讨了一般/疾病特征和骨转换标志物与骨密度的关系。
JDM 患者（n=59）在发病后中位数 16.8 年（范围 6.6-27.0 年）进行检查，并与 59 名年龄/性别匹配的对照者进行比较。所有参与者均使用双能 X 线吸收法（DXA）测量全身和腰椎（脊柱）的骨密度，年龄≥20 岁的参与者还测量超远端桡骨、前臂和总髋部的骨密度。分析骨转换标志物，并探讨与结果的相关性。
全身和脊柱的骨密度 Z 评分（<-1SD）分别在 19%和 29%的患者和 7%和 9%的对照者中降低（p 值<0.05）。所有患者和<20 岁的患者全身和脊柱的骨密度和骨密度 Z 评分均低于各自的对照者。在年龄≥20 岁的参与者中，仅患者的前臂骨密度和骨密度 Z 评分低于对照者。在患者中，全身和/或脊柱的骨密度 Z 评分与随访时（是/否）使用泼尼松龙（年龄<20 岁）、炎症标志物（年龄≥20 岁）和干扰素γ诱导蛋白 10（IP-10）水平呈负相关（两个年龄组）。在所有患者中，随访时（是/否）使用泼尼松龙和年龄≥20 岁是全身和脊柱骨密度 Z 评分降低的独立相关因素。
在长期 JDM 中，儿童的脊柱和全身骨密度受损比成人更严重。与骨密度相关的因素包括泼尼松龙和炎症标志物，还发现了与 JDM 活动的生物标志物 IP-10 的新关联。
