Table 6

Relative risk for developing rheumatoid arthritis in patients, stratified for anti-cyclic citrullinated peptide (anti-CCP) antibodies


Nonsmoking
Smoking



Cases/controls
Relative risk (95% confidence interval)
Cases/controls
Relative risk (95% confidence interval)

Anti-CCP antibody-positive
     HLA-shared epitope-positive
33/41
1.00
71/49
1.67 (0.95–2.94)
     HLA-shared epitope-negative
62/33
2.05 (1.12–3.75)
143/21
7.61 (4.05–14.30)
Anti-CCP antibody-negative
     HLA-shared epitope-positive
40/41
1.00
52/49
1.11 (0.63–1.95)
     HLA-shared epitope-negative
23/33
0.71 (0.37–1.38)
31/21
1.92 (0.98–3.77)

The combination of carriage of HLA-shared epitope alleles or not, and ever or never smoking were compared for groups stratified for anti-CCP antibodies.

Kokkonen et al. Arthritis Research & Therapy 2007 9:R56   doi:10.1186/ar2214