Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Brazil.
Programa de Pós-Graduação em Biociências, Universidade do Estado do Rio de Janeiro, Brazil.
J Steroid Biochem Mol Biol. 2024 Oct;243:106582. doi: 10.1016/j.jsbmb.2024.106582. Epub 2024 Jul 9.
Plasma 25-dihydroxyvitamin D levels appear reduced in patients with obesity or type 2 diabetes, as reported in several observational studies. However, the association between these reduced hormone levels and metabolic parameters is unclear. In any case, vitamin D supplementation in patients with Metabolic Syndrome is standard. Still, the impacts of this supplementation on conditions such as glycemia, blood pressure, and lipidemia are debatable. Based on this question, we carried out a systematic review and meta-analysis of randomized clinical trials in Brazil, Europe, and the United States that analyzed the effects of vitamin D supplementation on Metabolic Syndrome parameters in patients with obesity or type 2 diabetes. Our search yielded 519 articles and included 12 randomized controlled trials in the meta-analysis. Vitamin D supplementation had no effect on any of the outcomes analyzed (fasting blood glucose and insulinemia, glycated hemoglobin, HOMA index, systolic and diastolic blood pressure, weight, waist circumference, total cholesterol, LDL and HDL, and triglycerides). However, subgroup analyses indicated that using vitamin D up to 2000 IU daily reduced participants' fasting blood glucose and glycated hemoglobin. Furthermore, the intervention reduced diastolic blood pressure only in participants with vitamin D deficiency. At least two studies showed a high risk of bias using the Rob2 protocol. According to the GRADE protocol, the evidence quality varied from moderate to very low. These results indicate that vitamin D supplementation does not improve patients' metabolic parameters and that the association between plasma 25-dihydroxyvitamin D levels and Metabolic Syndrome may not be causal but caused by other confounding characteristics. However, in any case, the quality of evidence is still low, and more randomized clinical trials are essential to clarify these relationships.
已有多项观察性研究报告称，肥胖症或 2 型糖尿病患者的血浆 25-羟维生素 D 水平似乎较低。然而，这些激素水平降低与代谢参数之间的关联尚不清楚。在任何情况下，代谢综合征患者补充维生素 D 都是标准的。尽管如此，这种补充对血糖、血压和血脂等情况的影响仍存在争议。基于这个问题，我们对巴西、欧洲和美国的随机临床试验进行了系统评价和荟萃分析，这些试验分析了肥胖症或 2 型糖尿病患者补充维生素 D 对代谢综合征参数的影响。我们的检索结果产生了 519 篇文章，并在荟萃分析中纳入了 12 项随机对照试验。维生素 D 补充对任何分析结果（空腹血糖和胰岛素血症、糖化血红蛋白、HOMA 指数、收缩压和舒张压、体重、腰围、总胆固醇、LDL 和 HDL、以及甘油三酯）均无影响。然而，亚组分析表明，每天使用 2000IU 以下的维生素 D 可降低参与者的空腹血糖和糖化血红蛋白。此外，该干预措施仅降低了维生素 D 缺乏症患者的舒张压。至少有两项研究使用 Rob2 方案显示出高偏倚风险。根据 GRADE 方案，证据质量从中等到非常低不等。这些结果表明，维生素 D 补充并不能改善患者的代谢参数，而且血浆 25-羟维生素 D 水平与代谢综合征之间的关联可能不是因果关系，而是由其他混杂特征引起的。然而，在任何情况下，证据质量仍然较低，需要更多的随机临床试验来阐明这些关系。
