Response to: ‘Corresponence on ‘Shared epitope defines distinct associations of cigarette smoking with levels of anticitrullinated protein antibody and rheumatoid factor’ by Ishikawa et al’ by Regueiro and Gonzalez

Abstract

Correspondence response Figure 1 Cigarette smoking affects ACPA levels only in patients with SE alleles while cigarette smoking per se affects high RF levels regardless of SE allele status. (A) The association of smoking at the time of disease onset (SaO) with high ACPA or RF levels were evaluated conditioning on presence of SE alleles and high levels of RF or ACPA. ORs are indicated by dots and numbers, and 95% CIs are indicated by two-sided lines. (B, C) The associations of SaO with high ACPA or RF levels with or without SE alleles were evaluated referring never-smokers without SE alleles. Patients were stratified according to levels of autoantibodies (B; high ACPA without high RF or high RF without high ACPA) or serotypes (C; ACPA+RF or ACPA-RF+). ORs are indicated by dots and numbers, and 95% CIs are indicated by two-sided lines. The numbers of patients (case/total) are also indicated. High ACPA or RF: top quartile of ACPA or RF positive patients. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. ACPA, anticitrullinated cyclic peptide/ protein antibody; RF, rheumatoid factor; SaO, smokers at the time of onset; SE, shared epitope.