Vitamin D Supplementation Reduces CRP Levels in Postmenopausal Women: Study
Vitamin D supplementation has been suggested to have potential benefits in reducing inflammation and blood pressure, particularly in postmenopausal women. However, the evidence from randomized controlled trials (RCTs) on the relationship between vitamin D supplementation and inflammatory markers such as C-reactive protein (CRP), as well as blood pressure, remains inconclusive. A recent systematic review and meta-analysis aimed to provide more robust evidence on the effects of vitamin D supplementation on CRP, systolic blood pressure (SBP), and diastolic blood pressure (DBP) in postmenopausal women.
Previous observational studies have indicated an inverse relationship between vitamin D supplementation and CRP levels, suggesting a potential anti-inflammatory effect. However, RCTs have not consistently confirmed this association. This study was published in the Journal of the Academy of Nutrition and Dietetics by Jiang Q. and colleagues.
A systematic search of four databases (PubMed, Web of Science, Embase, and Scopus) was conducted to identify relevant RCTs published in international scientific journals up to January 2023. Changes in CRP, SBP, and DBP from baseline were compared between postmenopausal women who received vitamin D supplementation and those who did not (controls). The meta-analysis utilized the random-effects model to compute overall effect sizes, summarized as mean difference (MD) with 95% confidence intervals (CIs). Heterogeneity among studies was assessed using Cochrane's Q test and I² statistic, while publication bias was evaluated using funnel plots and Egger's test.
Key Findings:
• Seven studies were included in the meta-analysis, comprising 6 arms each for CRP, SBP, and DBP.
• Vitamin D supplementation significantly reduced CRP concentrations in postmenopausal women (MD = -0.65 mg/L; 95% CI -0.93 to -0.37 mg/L; P < .001).
• Studies with a duration of more than 3 months and those involving doses of ≤1,000 IU/d showed greater reductions in CRP levels after vitamin D supplementation.
• However, vitamin D supplementation did not significantly reduce SBP (MD = -1.06 mm Hg; 95% CI -2.43 to 0.30 mm Hg; P = .127) or DBP (MD = 0.003 mm Hg; 95% CI -0.86 to 0.86 mm Hg; P = .994) compared with control groups.
This meta-analysis suggests that vitamin D supplementation is associated with reduced CRP concentrations in postmenopausal women. However, no significant effects were observed on systolic or diastolic blood pressure levels. These findings provide valuable insights into the potential anti-inflammatory effects of vitamin D supplementation in this population. Further research is needed to elucidate the mechanisms underlying these effects and to explore the clinical implications for cardiovascular health in postmenopausal women.
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