ORs of developing RA (overall) for subjects worked in cold indoor by duration, intensity, cumulative dose and cessation
| Duration (number of years) | Cases/controls | OR* (95% CI) | OR† (95% CI) |
| Unexposed | 2783/4815 | 1.0 (ref.) | 1.0 (ref.) |
| <10 | 85/98 | 1.5 (1.1 to 2.0) | 1.3 (0.9 to 1.8) |
| 10–19 | 45/46 | 1.7 (1.1 to 2.5) | 1.5 (0.9 to 2.4) |
| ≥20 | 43/31 | 2.5 (1.5 to 4.0) | 2.0 (1.2 to 3.4) |
| p for trend | <0.001 | <0.001 | |
| Intensity (hours/week) | |||
| Unexposed | 2783/4815 | 1.0 (ref.) | 1.0 (ref.) |
| <10 | 52/74 | 1.2 (0.9 to 1.8) | 1.0 (0.7 to 1.5) |
| 10–19 | 27/25 | 1.9 (1.1 to 3.3) | 1.9 (1.1 to 3.6) |
| ≥20 | 77/64 | 2.1 (1.5 to 2.9) | 1.8 (1.2 to 2.6) |
| p for trend | <0.001 | <0.001 | |
| Cumulative dose (work-years) | |||
| Unexposed | 2783/4815 | 1.0 (ref.) | 1.0 (ref.) |
| <5 | 100/127 | 1.4 (1.0 to 1.8) | 1.2 (0.9 to 1.7) |
| 5–9 | 27/16 | 2.8 (1.5 to 5.3) | 1.9 (1.0 to 3.9) |
| ≥10 | 29/18 | 2.8 (1.5 to 5.1) | 2.4 (1.3 to 4.6) |
| p for trend | <0.001 | <0.001 | |
| Cessation (number of years) | |||
| Unexposed | 2783/4815 | 1.0 (ref.) | 1.0 (ref.) |
| <10 | 53/50 | 1.8 (1.2 to 2.6) | 1.6 (1.1 to 2.5) |
| 10–19 | 33/40 | 1.3 (0.8 to 2.2) | 1.2 (0.7 to 2.0) |
| ≥20 | 27/38 | 1.3 (0.8 to 2.1) | 1.2 (0.7 to 2.0) |
| p for trend | 0.001 | 0.023 | |
*OR adjusted for age (10 strata) sex, residential area and recruitment time period (1996–2006 and 2006–2014).
†OR adjusted for age (10 strata) sex, residential area, recruitment time period (1996–2006 and 2006–2014), cigarette smoking, body mass index, alcohol consumption, university education and silica exposure.
Cumulative dose is the product of duration and intensity.
One work-year is equivalent to 2080 hours.