CCL20 and inflammatory bowel disease: Third, we applied rigorous threshold-based univariable and multivariable linear regression modeling approaches to control for potential confounders like IBD diagnosis37,44, sex51, age51,52, BMI52, smoking status53, cholecalciferol supplementation43, disease activity44,45, and CRP levels44,52 that might influence VD status and CCL20 levels.