GSTM1 and rheumatoid arthritis: We also compared individuals with no copies of GSTM1 with individuals with ≥2 copies and found similar results; GSTM1 CNV and development of RA OR: 0.95 95% CI: 0.74–1.24, smoking (ORever smoker: 0.94 95% CI: 0.66–1.36) (ORnever smoker: 1.02 95% CI: 0.64–1.65) and SE (ORno SE: 1.06 95% CI: 0.68–1.65) (ORyes SE: 0.84 95% CI: 0.60–1.17).