Table 2

Association of PADI4 haplotypes, HLA-DRB1 SE alleles and smoking with susceptibility to anti-CCP-positive and -negative RA*

Controls, No

All RA cases

anti-CCP-positive RA

anti-CCP-negative RA

Subgroup

No.

OR (95% CI)

No.

OR (95% CI)

No.

OR (95% CI)

GTG-negative†

378

366

1

218

1

39

1

GTG-positive

625

945

1.64 (1.31 to 2.05)

602

1.73 (1.34 to 2.23)

106

1.75 (1.15 to 2.68)

SE-negative

644

429

1

226

1

71

1

SE-positive

359

882

4.31 (3.49 to 5.32)

594

5.18 (4.54 to 7.45)

74

2.31 (1.57 to 3.41)

Non-smoking

856

1,089

1

692

1

119

1

Smoking

134

197

2.28 (1.47 to 3.52)

119

2.17 (1.29 to 3.63)

26

2.77 (1.30 to 5.90)

* Values are the number of subjects. OR and 95% CI for GTG carriage versus non-carriage were adjusted for age, sex, SE alleles and smoking. OR and 95% CI for SE carriage versus non-carriage were adjusted for age, sex, GTG carriage and smoking. OR and 95% CI for smoking versus non-smoking were adjusted for age, sex, GTG carriage and SE alleles. RA, rheumatoid arthritis; anti-CCP, anti-cyclic citrullinated peptide autoantibody; OR, odds ratios; CI, confidence intervals.

† The letters in PADI4 haplotypes represent nucleotides in padi4_89, padi4_90, and padi4_92 SNPs, respectively. Extremely rare haplotypes ACG (n = 4), and GCC (n = 1) were excluded from analysis. Three subjects (two RA patients and one control) who carried ACC and a rare haplotype were excluded from the analysis and hence the GTG-negative subjects carried only ACC/ACC.

Bang et al. Arthritis Research & Therapy 2010 12:R115   doi:10.1186/ar3051