Table 3 ORs with 95% CI for developing anti-cyclic citrullinated peptide (anti-CCP) antibodies in rheumatoid arthritis for ever-smokers compared with never-smokers by duration of smoking
No. of years of smokingAnti-CCP+Anti-CCP–OR (95% CI)
<1027110.7 (0.3 to 1.6)
10–1929100.8 (0.4 to 2.0)
⩾204233.7 (1.1 to 12.8)
Never smokers93281 (–)

  • Anti-CCP+, presence of anti-CCP antibodies; anti-CCP–, absence of anti-CCP antibodies.