MUC5B and rheumatoid arthritis: Among the risk factors associated with the development of ILD in RA, some are also shared with IPF, such as male gender, older age, a history of smoking, and MUC5B variants, whereas others are disease-specific, such as Rheumatoid Factor and Anti-Citrullinated Protein Antibody (ACPA) positivity, older age at diagnosis, and higher disease activity [24,25].