Table 3

 Relative risk of developing rheumatoid factor (RF) positive rheumatoid arthritis, RF negative rheumatoid arthritis, and rheumatoid arthritis overall for subjects who were not higher non-manual employees compared with higher non-manual employees, by sex

Ca/CoRR*95% CIRR**95% CI
RF+ RANot higher non-manual employees298/5291.61.1 to to 2.6
Higher non-manual employees†35/991.01.0
RF− RANot higher non-manual employees155/5290.80.5 to to 1.5
Higher non-manual employees†34/991.01.0
Total RANot higher non-manual employees453/5291.20.8 to to 1.9
Higher non-manual employees†69/991.01.0
Ca/CoRR*95% CIRR**95% CI
RF+ RANot higher non-manual employees120/2071.20.8 to to 2.2
Higher non-manual employees†34/731.01.0
RF− RANot higher non-manual employees53/2071.00.6 to to 1.8
Higher non-manual employees†20/731.01.0
Total RANot higher non-manual employees173/2071.20.8 to to 1.8
Higher non-manual employees†54/731.01.0
Ca/CoRR§95% CIRR§§95% CI
Values are relative risks with 95% confidence intervals.
*RR adjusted for age and residential area.
**RR adjusted for age, residential area, and smoking.
§RR adjusted for age, residential area, and sex.
§§RR adjusted for age, residential area, sex, and smoking.
†Reference group.
Ca/Co, number of exposed cases/number of exposed controls; CI, confidence interval; RF, rheumatoid factor; RR, relative risk.
RF+ RANot higher non-manual employees418/7361.41.0 to to 2.1
Higher non-manual employees†69/1721.01.0
RF− RANot higher non-manual employees208/7360.80.6 to to 1.3
Higher non-manual employees†54/1721.01.0
Total RANot higher non-manual employees626/7361.20.9 to to 1.6
Higher non-manual employees†123/1721.01.0