Frequency of each allele (%) of TNF-α and IL-1Ra in the combined patient and control groups and the relative risk (RR)
| Allele | Subjects | Controls | RR |
| G/TNF1 | 82.5 | 80.2 | 1.03 |
| A/TNF2 | 17.5 | 19.8 | 0.88 |
| IL-1Ra*1 | 82.5 | 78.3 | 1.06 |
| IL-1Ra*2 | 15 | 20 | 0.79 |
| IL-1Ra*3 | 2.5 | 1.5 | 1.67 |
| IL-1Ra*4 | — | 0.2 | — |
| IL-1Ra*5 | — | — | — |