The effect of vitamin D supplementation on endothelial function: An umbrella review of interventional meta-analyses

There is no consensus in the existing literature regarding the effect of vitamin D supplementation on endothelial function. This umbrella review aimed to assess meta-analyses of randomized controlled trials (RCTs) conducted in this field.

We systematically searched English-language databases, including PubMed, Embase, Scopus, and Web of Science, up to January 2024. Flow-Mediated Dilation (FMD), Pulse Wave Velocity (PWV), and Augmentation Index (AIx) were the primary endpoints evaluated. A total of 16 meta-analyses were included in the review. The results indicated that vitamin D supplementation significantly improved FMD as assessed by Standardized Mean Difference (SMD) (SMD = 0.72, 95 % CI: 0.34, 1.11; p < 0.001; I² = 79.4 %, p < 0.001) and Weighted Mean Difference (WMD) (WMD = 1.91; 95 % CI: 0.66, 3.16; p = 0.003; I² = 94.5 %, p < 0.001). PWV also showed a modest but significant improvement (SMD = -0.06, 95 % CI: -0.12, -0.00; p = 0.03; I² = 0.0 %, p = 0.66). However, vitamin D had no significant impact on AIx based on SMD (SMD = -0.03, 95 % CI: -0.13, 0.06; p = 0.48; I² = 0.0 %, p = 0.49) or WMD (WMD = 0.02, 95 % CI: -2.22, 2.25; p = 0.98; I² = 29.2 %, p = 0.23).

These findings suggest that vitamin D supplementation may be a beneficial intervention for improving endothelial function, particularly in populations with low FMD. The effects on PWV were modest, while AIx remained unaffected.

PROSPERO, CRD42024451215.