Background Emerging evidence showed promising effects of vitamin D on headaches characteristics. Thus, it seems there is still a need for more researches to clarify the mechanisms by which this vitamin exerts anti-migraine effects. Methods The present study was conducted as a 16-week randomized double-blind placebo-controlled trial on 80 episodic migraine patients allocated in 2 parallel groups each consisted of 40 patients who received vitamin D 2000 IU/d or placebo. At baseline and after the intervention completion, headache diaries and migraine disability assessment questionnaire (MIDAS) were used to assess migraine related variables in patients. Also, interictal serum concentration of calcitonin gene-related peptide (CGRP) (as the dominant mediator of migraine pain pathogenesis) was evaluated using ELISA method. Results The mean (SD) of age in the vitamin D and placebo groups was 37 (8) and 38 (12) years, respectively. ANCOVA test adjusted for baseline values, and confounders showed vitamin D supplementation resulted in a significant improvement in MIDAS score after 12 weeks in the intervention group (21.49 (16.22–26.77)) compared to placebo (31.16 (25.51–36.82) P value: 0.016). Moreover, after controlling for baseline levels, and other variables using ANCOVA, CGRP level was appeared to be significantly lower following vitamin D supplementation (153.26 (133.03–173.49) ng/L) than the patients in the placebo arm (188.35 (167.15–209.54) ng/L) ( P value = 0.022). Conclusion According to the current findings, vitamin D supplementation in episodic migraineurs, particularly in those with migraine with aura, may potentially improve migraine headache characteristics and disability probably through attenuating CGRP levels. Therefore, these results could provide a new insight into anti-nociceptive effects of vitamin D; however, more studies are required to confirm our findings. Trial registration The trial is registered in the Iranian registry of clinical trials (IRCT) at 11 July 2018, with IRCT code: IRCT20151128025267N6 .

中文翻译：

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补充维生素 D 对发作性偏头痛患者发作间期血清降钙素基因相关肽 (CGRP) 水平的影响：一项随机双盲安慰剂对照试验的事后分析

背景 新出现的证据表明维生素 D 对头痛特征有良好的影响。因此，似乎仍然需要更多的研究来阐明这种维生素发挥抗偏头痛作用的机制。方法 本研究是一项为期 16 周的随机双盲安慰剂对照试验，对 80 名发作性偏头痛患者进行了 2 个平行组，每组由 40 名接受 2000 IU/d 维生素 D 或安慰剂的患者组成。在基线和干预完成后，头痛日记和偏头痛残疾评估问卷 (MIDAS) 用于评估患者的偏头痛相关变量。此外，使用ELISA方法评估了降钙素基因相关肽（CGRP）（作为偏头痛发病机制的主要介质）的发作间期血清浓度。结果维生素 D 和安慰剂组的平均年龄 (SD) 分别为 37 (8) 和 38 (12) 岁。ANCOVA 测试针对基线值进行了调整，混杂因素显示，与安慰剂（31.16（25.51–36.82）P 值：0.016）相比，干预组在 12 周后补充维生素 D 显着改善了 MIDAS 评分（21.49 (16.22–26.77)） ）。此外，在使用 ANCOVA 控制基线水平和其他变量后，补充维生素 D 后的 CGRP 水平（153.26 (133.03–173.49) ng/L）似乎比安慰剂组的患者 (188.35 (167.15–209.54) ) ng/L)（P 值 = 0.022）。结论 根据目前的研究结果，对偶发性偏头痛患者，尤其是先兆偏头痛患者，补充维生素 D，可能通过降低 CGRP 水平来潜在地改善偏头痛特征和残疾。因此，这些结果可以为维生素 D 的抗伤害作用提供新的见解；然而，需要更多的研究来证实我们的发现。试验注册 本试验于 2018 年 7 月 11 日在伊朗临床试验注册中心（IRCT）注册，IRCT 代码：IRCT20151128025267N6。