Fu Jia, Sun Junfang, Zhang Chao
Department of Neurology, Chifeng Municipal Hospital, Chifeng, China.
The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, Baotou, China.
Front Neurol. 2022 Aug 18;13:970111. doi: 10.3389/fneur.2022.970111. eCollection 2022.
Previous observational studies have supported the hypothesis that vitamin D supplementation protects against stroke. However, several current intervention studies contradict this observation. Therefore, we conducted a meta-analysis to investigate further the association between vitamin D supplementation and the risk of stroke.
This meta-analysis was conducted in accordance with the PRISMA statement and included all the randomized controlled trials (RCTs) that analyzed the relationship between vitamin D supplementation and the risk of stroke. A literature search strategy was established, and the following Medical Search Terms (MeSH) were used: "vitamin D," "Calcitriol," "Calcifediol," "Cholecalciferol," "25-Hydroxyvitamin D 2," "ergocalciferols," "stroke," and stroke-derived terms. We searched for articles published before January 2022 in several databases, namely, PubMed, Web of Science, EMBASE, and The Cochrane Library. We also reviewed references included in relevant published meta-analyses and searched the http://www.ClinicalTrials.gov website for additional RCTs. The test and were utilized to assess the degree of heterogeneity among the studies. Review Manager 5.3 and STATA16.0 software programs were used to assess the literature quality and perform statistical analyses.
In total, twenty-four RCTs (86,202 participants) were included. There was no statistical heterogeneity among the RCTs ( = 0.0%, = 0.94) included in this meta-analysis. We determined that vitamin D supplementation was not associated with a reduced risk of stroke compared with the placebo (RR = 1.02, 95% CI: 0.93-1.13, = 0.65). In total, 10 studies only included women, and 14 studies included women and men among the 24 RCTs. Therefore, we performed a subgroup analysis based on sex. After the subgroup analysis, the effect remained statistically insignificant (mixed-sex group: RR = 1.06, 95% CI: 0.93-1.22, = 0.37, women group: RR = 0.98, 95% CI: 0.86-1.13, = 0.80). The results were generally comparable, based on age, body mass index (BMI), follow-up period, baseline 25-hydroxyvitamin D (25(OH)D) levels, the designated endpoint, latitude, vitamin D dosage, type of vitamin D administered, and an absence or presence of concurrent calcium supplementation ( > 0.05).
Our study revealed that additional vitamin D supplementation did not reduce the risk of stroke. Therefore, additional RCTs of similar design should not be encouraged to assess any association between vitamin D supplementation and reduced stroke risk.
既往观察性研究支持补充维生素D可预防中风这一假说。然而，当前一些干预性研究与这一观察结果相矛盾。因此，我们进行了一项荟萃分析，以进一步研究补充维生素D与中风风险之间的关联。
本荟萃分析按照PRISMA声明进行，纳入了所有分析补充维生素D与中风风险关系的随机对照试验（RCT）。制定了文献检索策略，并使用了以下医学检索词（MeSH）：“维生素D”、“骨化三醇”、“骨化二醇”、“胆钙化醇”、“25-羟基维生素D2”、“麦角钙化醇”、“中风”以及中风衍生词。我们在多个数据库中检索了2022年1月之前发表的文章，即PubMed、科学网、EMBASE和考克兰图书馆。我们还查阅了相关已发表荟萃分析中包含的参考文献，并在http://www.ClinicalTrials.gov网站上搜索了其他RCT。采用I²检验和τ²评估研究间的异质性程度。使用Review Manager 5.3和STATA16.0软件程序评估文献质量并进行统计分析。
总共纳入了24项RCT（86202名参与者）。本荟萃分析纳入的RCT之间无统计学异质性（I² = 0.0%，τ² = 0.94）。我们确定，与安慰剂相比，补充维生素D与中风风险降低无关（RR = 1.02，可信区间95%：0.93 - 1.13，P = 0.65）。在这24项RCT中，共有10项研究仅纳入女性，14项研究纳入了女性和男性。因此，我们按性别进行了亚组分析。亚组分析后，效应仍无统计学意义（混合性别组：RR = 1.06，可信区间95%：0.93 - 1.22，P = 0.37，女性组：RR = 0.98，可信区间95%：0.86 - 1.13，P = 0.80）。基于年龄、体重指数（BMI）、随访期、基线血清25-羟基维生素D（25(OH)D）水平、指定终点、纬度、维生素D剂量、所给予维生素D的类型以及是否同时补充钙，结果总体具有可比性（P > 0.05）。
我们的研究表明，额外补充维生素D并不能降低中风风险。因此，不应鼓励开展类似设计的额外RCT来评估补充维生素D与降低中风风险之间的任何关联。
