Background Evidence from the literature suggests that vitamin D has indirect antimicrobial effects and may be associated with a reduced risk of infections. This study aimed to systematically evaluate the association between vitamin D deficiency and the risk of developing surgical site infections (SSIs). Methods All types of studies will be included in the systematic review. Up to December 2025, Medline, Embase, Cochrane, Web of Science, CINAHL, Google Scholar, ClinicalTrials.gov, WHO-ICTRP, Cochrane Central Register of Controlled Trials, and relevant citations will be searched. The primary outcome will be the development of SSIs. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Meta-analysis will be performed using bias-adjusted inverse variance heterogeneity methods. The risk of bias will be assessed using the MASTER scale, and the certainty of evidence will be determined using the GRADE framework. Discussion Although many risk factors for SSIs have been identified, the role of vitamin D remains unclear. SSIs impose a significant burden on patients and healthcare systems. This systematic review and meta-analysis aims to comprehensively evaluate the impact of vitamin D on SSI risk by including all relevant studies without language restrictions, using rigorous methodology in accordance with the Cochrane Handbook and PRISMA guidelines. If an association is established, preoperative screening and optimization of vitamin D levels could help reduce the burden of SSIs. Systematic review registration PROSPERO registration number 427175.
Farsakoury et al. (Wed,) studied this question.