Interaction between smoking, the shared epitope, and anti–cyclic citrullinated peptide: A mixed picture in three large North American rheumatoid arthritis cohorts

Abstract

Unlike the EIRA data, we could not confirm a major gene-environment interaction for anti-CCP formation between shared epitope alleles and smoking in 3 North American RA cohorts. Our data indicate a need for further studies to address the full range of environmental factors other than smoking that may be associated with citrullination and RA.