Serum Vitamin D Levels and Its Relationship With Keloid, Acne or Hypertrophic Scar: A Two‐Sample Mendelian Randomization Study

Background Previous studies reported that patients with keloid, acne, or hypertrophic scar (HS) had lower serum vitamin D levels compared to healthy controls. Whereas, these works failed to verify their causal relationships. Hence, we performed a Mendelian randomization (MR) aimed to investigate the causal relationship between vitamin D and keloid, acne, or HS. Methods Utilizing summary datasets from genome‐wide association studies, we conducted a two‐sample MR analysis to explore the causal relationship between vitamin D and keloid, acne, or HS. The inverse‐variance weighted MR approach served as the primary analysis, with additional support from various sensitivity methods, including MR‐Egger, weighted median, simple mode, weighted mode, and MR‐PRESSO, to enhance the reliability of our findings. Results From our MR analyses, no causal relationships were found between vitamin D level and keloid (OR: 1.15, 95% CI: 0.853–1.16, p = 0.36), acne (OR: 0.94, 95% CI: 0.66–1.30, p = 0.65) or HS (OR: 1.20, 95% CI 0.79–1.82, p = 0.40) formation. After eliminating outliers through MR‐PRESSO, no significant associations were found between serum vitamin D level and keloid, acne, as well as HS. Conclusion Our findings, backed by rigorous IV selection and consistent outcomes across various MR approaches, suggest no causal link between serum 25(OH)D levels and keloid, acne, or HS. While vitamin D is involved in wound healing, its connection to these conditions may not be straightforward, emphasizing the need for further research.