Serum 25-hydroxyvitamin D levels in infants with retinopathy of prematurity: a systematic review and meta-analysis

Purpose To evaluate the association between serum vitamin D levels and retinopathy of prematurity (ROP) through a systematic review and meta-analysis. Methods A systematic search was conducted in PubMed, Embase, The Cochrane Library, Web of Science, and Scopus up to August 2026. All observational studies measuring vitamin D levels in infants with ROP were included. The standardized mean difference (SMD) was calculated using a random-effects model to assess differences in vitamin D levels between patients with ROP and healthy controls. The log odds ratio (OR) was computed to assess the association between vitamin D deficiency and the incidence of ROP. Results Ten relevant studies evaluating the relationship between vitamin D and ROP were included. Six studies, including 281 ROP infants, compared serum vitamin D levels between ROP and control groups. Five studies compared the risk of ROP development in the vitamin D-sufficient vs. deficient infants. Meta-analysis results revealed a significantly lower vitamin D level in ROP infants vs. control (SMD: -0.94, 95% CI: -1.21 to -0.67; I² = 48.26%, p-value < 0.001). Additionally, vitamin D levels were significantly lower in infants requiring ROP treatment than in the monitoring group. Furthermore, infants with vitamin D deficiency had a higher risk of ROP development (OR: 6.69, 95% CI: 1.65 to 27.4, p = 0.01). Conclusion The findings of the current study suggest that vitamin D status may be associated with the risk and severity of ROP in preterm infants. Further well-designed prospective studies are needed to determine whether vitamin D status has an independent role in ROP and whether supplementation provides clinical benefit.