Relative risk (RR) with 95% confidence interval (95% CI) of developing seropositive rheumatoid arthritis for 18–70 years old female and male ex-smokers compared with never-smokers by number of years since smoking cessation
| Number of years* | Number of exposed cases | RR† | 95% CI |
|---|---|---|---|
| *Number of years between smoking cessation and index year. | |||
| †Relative risk adjusted for age, residential area, and sex. | |||
| 1–9 | 74 | 2.2 | 1.4 to 3.3 |
| 10–19 | 41 | 1.5 | 0.9 to 2.5 |
| ⩾20 | 25 | 1.0 | 0.5 to 1.9 |