OR with 95% CI of developing RA for subjects categorised by smoking and BMI status stratified by gender
| ACPA-positive RA | ACPA-negative RA | ||||
| Smoking | BMI | Ca/Co* | OR (95% CI)† | Ca/Co* | OR (95% CI)† |
| Women | |||||
| – | 18.5–25 | 327/1089 | 1.0 (reference) | 186/1089 | 1.0 (reference) |
| – | >25 | 227/809 | 1.0 (0.8 to 1.2) | 153/809 | 1.1 (0.9 to 1.4) |
| + | 18.5–25 | 617/1337 | 1.5 (1.2 to 1.7) | 257/1337 | 1.1 (0.9 to 1.3) |
| + | >25 | 521/887 | 2.0 (1.7 to 2.3) | 259/887 | 1.6 (1.3 to 2.0) |
| AP 0.3 (0.1 to 0.4) | AP 0.3 (0.07 to 0.5) | ||||
| Men | |||||
| – | 18.5–25 | 71/288 | 1.0 (reference) | 53/288 | 1.0 (reference) |
| – | >25 | 84/402 | 0.9 (0.6 to 1.2) | 78/402 | 1.0 (0.7 to 1.6) |
| + | 18.5–25 | 216/339 | 2.5 (1.8 to 3.4) | 85/339 | 1.2 (0.8 to 1.8) |
| + | >25 | 276/621 | 1.7 (1.3 to 2.3) | 159/621 | 1.2 (0.9 to 1.8) |
Attributable proportion due to interaction between smoking and overweight/obesity.
*Number of exposed cases and controls.
†Adjusted for age, residential area, ancestry and study.
ACPA, anticitrullinated peptide antibody; BMI, body mass index; RA, rheumatoid arthritis.