PRTN3 and rheumatoid arthritis: When subdividing the subjects according to smoking status, we found that presence of GSTM1 is significantly associated with risk for ACPA-positive RA among never smoking women ≥60 years old (OR: 2.00 95% CI: 1.07–3.74) and we also found a trend for association between presence of GSTM1 and ACPA positive RA among SE-negatives (OR: 2.02 95% CI: 0.98–4.16) (Table 5).