Table 3.
Association between the history of infections and RA
| Variables | Controls | Cases | OR (95% CI) | Adjusted OR* (95% CI) | ||
|---|---|---|---|---|---|---|
| N | % | N | % | |||
| Infection ever before diagnosis | ||||||
| Lower respiratory tract | 31,400 | 34.9 | 10,050 | 44.3 | 1.56 (1.51–1.61) | 1.37 (1.32–1.41) |
| Upper respiratory tract | 41,786 | 46.4 | 12,258 | 54.1 | 1.42 (1.38–1.47) | 1.26 (1.22–1.31) |
| Gastrointestinal | 8352 | 9.3 | 2699 | 11.9 | 1.33 (1.27–1.40) | 1.19 (1.13–1.25) |
| Urinary tract | 11,037 | 12.3 | 3179 | 14 | 1.19 (1.13–1.24) | 1.07 (1.02–1.12) |
| Infection episodes | ||||||
| 0 | 34,899 | 38.8 | 6835 | 30.1 | Reference | Reference |
| 1 | 18,503 | 20.6 | 4366 | 19.3 | 1.26 (1.21–1.32) | 1.22 (1.72–1.28) |
| 2 | 11,041 | 12.3 | 2990 | 13.2 | 1.48 (1.41–1.56) | 1.42 (1.35–1.49) |
| 3 | 7091 | 7.9 | 2066 | 9.1 | 1.63 (1.54–1.73) | 1.54 (1.46–1.64) |
| ≥ 4 | 18,479 | 20.5 | 6420 | 28.3 | 2.02 (1.93–2.11) | 1.86 (1.78–1.94) |
| No. of treated URT | ||||||
| 0 | 8466 | 20.3 | 2078 | 17.0 | Reference | Reference |
| 1 | 16,536 | 39.6 | 4510 | 36.8 | 1.11 (1.05–1.18) | 1.10 (1.04–1.17) |
| 2 | 7052 | 16.9 | 2236 | 18.2 | 1.29 (1.21–1.38) | 1.27 (1.19–1.50) |
| 3 | 3554 | 8.5 | 1233 | 10.1 | 1.41 (1.30–1.53) | 1.39 (1.28–1.51) |
| ≥ 4 | 6178 | 14.8 | 2201 | 18.0 | 1.45 (1.36–1.55) | 1.42 (1.32–1.52) |
| No. of untreated URT | ||||||
| 0 | 21,981 | 52.6 | 6510 | 53.1 | Reference | Reference |
| 1 | 13,893 | 33.2 | 3908 | 31.9 | 0.95 (0.91–0.99) | 0.95 (0.91–1.00) |
| 2 | 3714 | 8.9 | 1132 | 9.2 | 1.03 (0.96–1.11) | 1.02 (0.95–1.07) |
| 3 | 1274 | 3 | 385 | 3.1 | 1.02 (0.91–1.15) | 1.00 (0.89–1.13) |
| ≥ 4 | 924 | 2.2 | 323 | 2.6 | 1.18 (1.04–1.34) | 1.14 (1.00–1.29) |
*Adjusted for age, BMI, smoking status, Charlson comorbidity index, alcohol, and presence/absence of LRT, URT, GII, and UTI