Table 5 |
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|
Odds ratios for developing ACPA-positive RA and ACPA-negative RA in subjects exposed to different combinations of smoking and presence of HLA-DRB1*04:05 or non-HLA-DRB1*04:05 SE alleles, compared with never-smokers without SE alleles in MyEIRA |
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|
No SE alleles |
HLA-DRB1*04:05 SE allelesab |
Any non-HLA-DRB1*04:05 SE allelesc |
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|
|
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|
Ca/Co |
OR (95% CI) |
Ca/Co |
OR (95% CI) |
Ca/Co |
OR (95% CI) |
|
|
|
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|
ACPA-positive RA |
||||||
|
Never-smokers |
266/986 |
1.0 |
102/71 |
5.4 (3.8 to 7.5) |
152/130 |
3.1 (2.4 to 4.0) |
|
Ever-smokers |
30/52 |
3.1 (1.7 to 5.7) |
16/7 |
12.9 (4.7 to 35.3) |
15/1 |
82.4 (10.3 to 656.9) |
|
AP |
0.4 (-0.1 to 0.9) |
0.9 (0.8 to 1.1) |
||||
|
ACPA-negative RA |
||||||
|
Never-smokers |
254/986 |
1.0 |
20/71 |
1.1 (0.7 to 1.8) |
44/130 |
1.3 (0.9 to 1.9) |
|
Ever-smokers |
10/52 |
0.6 (0.2 to 2.0) |
1/7 |
0.6 (0.1 to 4.8) |
2/1 |
8.1 (0.7 to 93.0) |
|
|
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|
ACPA, anti-cyclic citrullinated proteins antibody; AP, attributable proportion due to interaction; Ca/Co, number of exposed cases/number of exposed controls; MyEIRA, Malaysian Epidemiological Investigation of Rheumatoid Arthritis; OR (95% CI), odds ratio and 95% confidence interval, adjusted for ethnicity, formal education, age, sex, residential area, calculated by means of unconditional logistic regression to increase power; RA, rheumatoid arthritis; SE, shared epitope. a HLA-DRB1*04:05 group was defined by the presence of either one or two copies of HLA-DRB1*04:05 allele. bIndividuals with first allele of HLA-DRB1*04:05 and second allele of a non-HLA-DRB1*04:05 SE (that is, HLA-DRB1*04:05/non-HLA-DRB1*04:05 SE) were not included in the interaction analysis (cases, 13; control, 1). cAny non-HLA-DRB1*04:05 SE alleles group was defined by the presence of either one or two copies HLA-DRB1*01:01, *01:02, *01:07, *04:01, *04:04, *04:08, *04:10, *10:01, and *10:03 alleles. |
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|
Too et al. Arthritis Research & Therapy 2012 14:R89 doi:10.1186/ar3813 |
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