ARD：特发性炎症性肌病患者血清维生素D水平低

既往研究发现，较低的维生素D水平与1型糖尿病、炎性肠病、系统性红斑狼疮、类风湿关节炎等多种自身免疫性疾病相关。为评估特发性炎性肌病（IIM）【包括多肌炎（PM）、皮肌炎（DM）、包涵体肌炎（IBM）、儿童DM（JDM）】患者对比健康对照组，其血清25（OH）维生素D的水平是否降低，来自瑞典卡罗林斯卡学院风湿病学系的Payam Azali等人进行了一项研究。研究结果发表于2013年4月的《风湿病学年鉴》（Ann Rheum Dis）杂志上。研究发现，特发性炎性肌病患者血清维生素D水平低。
研究纳入了149例IIM患者，以及290例在性别和血液样本采集月份方面相匹配的健康对照组人群，评估研究对象的血清25（OH）维生素D水平。维生素D水平在95%可信区间的OR值通过匹配（条件）逻辑回归模型进行确定。使用克鲁斯卡尔-瓦利斯二氏检验进行组间比较，P值＜0.05被认为有意义。
IIM患者血清25（OH）维生素D水平较健康对照组人群明显降低【平均值39（10-168）nmol/l vs 68（19-197）nmol/l；P=0.0001】。肌炎各亚组之间的维生素D水平无显著差别。如将维生素D水平分为缺乏（＜50nmol/l）、不足（50-74nmol/l）和正常（≥75nmol/l）三种等级，那么绝大部分肌炎患者处于缺乏组（PM68%、DMA65%、IBM53%），相比之下，健康对照组中只有60例（21%）处于缺乏组。IIM患者维生素D水平缺乏相比于正常的OR值为17.7（95%CI 8.1-38.6），维生素D水平不足相比于正常的OR值为2.4（95%CI 1.2-4.7）。
研究发现，如同其他一些自身免疫性疾病一样，大部分IIM患者的血清维生素D水平降低，其可被视为成年肌炎发病的危险因素。
与肌病相关的拓展阅读：

• 病例报告：氟哌啶醇致药物性心肌病一例
• JAMA：心肌纤维化是扩张型心肌病患者发生心源性猝死的独立预测因素
• JAMA：增强心脏MR可改善扩张性心肌病风险评估水平
• EUR HEART J：NT-proBNP有效预测肥厚型心肌病患者预后
• HEART RHYTHM :致心律失常性心肌病患者或存在心肌信号传导紊乱
• Circulation：肥厚性心肌病遗传外显率调查
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Low serum levels of vitamin D in idiopathic inflammatory myopathies.
OBJECTIVES
To evaluate serum levels of 25(OH) vitamin D in patients with idiopathic inflammatory myopathies (IIM) (polymyositis (PM), dermatomyosistis (DM), inclusion body myositis (IBM) and juvenile DM (JDM)) and to compare these with healthy controls.
METHODS
Serum samples from 149 patients with IIM and 290 healthy controls matched for gender and the month of blood sampling were analysed for 25(OH) vitamin D. ORs for vitamin D classes with 95% CI were calculated using a matched (conditional) logistic regression model. Groups were compared by the Kruskal-Wallis test and p values <0.05 were considered significant.
RESULTS
Patients with IIM had significantly lower serum levels of 25(OH) vitamin D than healthy controls (median 39 (10-168) nmol/l vs 68 (19-197) nmol/l; p=0.0001). There was no significant difference in vitamin D levels between the myositis subgroups. When vitamin D levels were subclassified into deficient (<50 nmol/l), insufficient (50-74 nmol/l) and normal (≥75 nmol/l), most of the patients with PM (68%), DM (65%) and IBM (53%) had deficient levels compared with only 60 (21%) healthy individuals. In patients with IIM the OR for deficient versus normal was 17.7 (95% CI 8.1 to 38.6) and the OR for insufficient versus normal was 2.4 (95% CI 1.2 to 4.7).
CONCLUSIONS
Low serum levels of vitamin D were found in most patients with IIM and may confer a risk factor for developing adult myositis, similar to some other autoimmune diseases.