MUC1 and interstitial lung disease: In terms of study design type, subgroup analysis revealed that the risk factors of AAV-ILD in the case-control study studies within age, KL-6, ESR, and BVAS were (WMDs = 11.18, 95 % CI: 6.59‒15.78), (WMDs = 540.94, 95 % CI: 355.27‒726.60), (WMDs = 27.79, 95 % CI: 15.12‒40.45), and (WMDs = −5.40, 95 % CI: −9.56‒−1.24), respectively.