Table 5

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


Non-T carrier (CC)
T carrier (CT, TT)



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

Anti-CCP antibody-positive
     Smoking-negative
59/511
1.00
37/146
2.17 (1.41–3.35)
     Smoking-positive
142/192
6.29 (4.51–8.77)
73/50
12.54 (8.11–19.40)
Anti-CCP antibody-negative
     Smoking-negative
47/511
1.00
17/146
1.36 (0.80–2.33)
     Smoking-positive
60/192
3.71 (2.51–5.46)
23/50
5.87 (3.46–9.95)

The combination of carriage or not of the 1858T variant of the PTPN22 gene 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