OR with 95% CI of developing RA for subjects with different combinations of alcohol consumption, smoking habits and HLA-SE status, compared with HLA-SE negative never smokers who consume alcohol
| Non-drinking | Smoking | HLA-SE | Total | ACPA-positive RA | ACPA-negative RA | |||
| CA/CO* | OR (95% CI)† | CA/CO* | OR (95% CI)† | CA/CO* | OR (95% CI)† | |||
| − | − | − | 214/476 | 1.0 (reference) | 72/476 | 1.0 (reference) | 142/476 | 1.0 (reference) |
| − | + | − | 438/663 | 1.5 (1.2 to 1.9) | 187/663 | 2.0 (1.5 to 2.8) | 251/663 | 1.2 (1.0 to 1.6) |
| + | − | − | 120/116 | 2.1 (1.5 to 2.9) | 44/116 | 2.4 (1.5 to 3.8) | 76/116 | 1.9 (1.3 to 2.7) |
| + | + | − | 121/104 | 2.4 (1.7 to 3.3) | 47/104 | 3.1 (2.0 to 4.8) | 74/104 | 2.0 (1.4 to 2.8) |
| − | − | + | 528/524 | 2.2 (1.8 to 2.7) | 367/524 | 4.7 (3.5 to 6.3) | 161/524 | 1.0 (0.8 to 1.5) |
| − | + | + | 1243/742 | 3.9 (3.2 to 4.7) | 946/742 | 9.3 (7.0 to 12.3) | 297/742 | 1.3 (1.0 to 1.6) |
| + | − | + | 251/108 | 5.0 (3.7 to 6.7) | 171/108 | 11.0 (7.6 to 15.9) | 80/108 | 2.1 (1.4 to 3.0) |
| + | + | + | 438/103 | 9.2 (6.9 to 12.2) | 359/103 | 25.3 (17.7 to 36.2) | 79/103 | 2.1 (1.5 to 3.1) |
| AP 0.6 (0.4 to 0.7)‡ AP 0.3 (0.06 to 0.5)§ EOR 2.8 (0.1 to 5.5)¶ | AP 0.7 (0.6 to 0.8)‡ AP 0.4 (0.2 to 0.6)§ EOR 10.0 (2.6 to 17.5)¶ | AP 0.008 (−0.4 to 0.4)‡ AP 0.003 (−0.5 to 0.5)§ EOR 0.01 (−1.3 to 1.3)¶ | ||||||
*Number of exposed CA and CO.
†Adjusted for age, gender, residential area, ancestry and study.
‡AP due to interaction (95% CI) of the OR due to second-order and third-order interaction between the three risk factors.
§AP due to interaction (95% CI) of the OR due to third-order interaction between the three risk factors.
¶EOR (95% CI) of triple exposed due to third-order interaction between the three risk factors.
ACPA, anticitrullinated protein antibodies; AP, attributable proportion; CA, cases; CO, controls; EOR, excess OR; HLA-SE, human leucocyte antigen-shared epitope; RA, rheumatoid arthritis.