In individuals with sufficient VD status [25-hydroxyvitamin D concentrations ≥ 20 ng/mL], a higher calcitriol/25-hydroxyvitamin D activation ratio showed a negative association with systemic CCL20 levels in HCs [β (95% CI) =  − 0.073 (− 0.117, − 0.028), p = 0.0020] and patients with ulcerative colitis [β (95% CI) =  − 0.020 (− 0.036, − 0.004), p = 0.017] in the univariable models. Here, CCL20 is linked to ulcerative colitis.