Table 1

Relative risk of developing rheumatoid factor (RF) positive rheumatoid arthritis, RF negative rheumatoid arthritis, and rheumatoid arthritis overall for subjects without a university degree compared with those with a university degree, by sex

		Ca/Co	RR*	95% CI	RR**	95% CI
Women
RF+ RA	No university degree	340/584	1.5	1.1 to 2.0	1.6	1.1 to 2.2
RF+ RA	University degree†	82/204	1.0	–	1.0	–

RF− RA	No university degree	170/584	0.9	0.7 to 1.3	0.8	0.6 to 1.3
RF− RA	University degree†	61/204	1.0	–	1.0	–

Total RA	No university degree	510/584	1.3	1.0 to 1.6	1.3	1.0 to 1.7
	University degree†	143/204	1.0	–	1.0	–


		Ca/Co	RR*	95% CI	RR**	95% CI
Men
RF+ RA	No university degree	162/260	2.1	1.3 to 3.6	2.0	1.1 to 3.6
RF+ RA	University degree†	22/75	1.0	–	1.0	–

RF to RA	No university degree	80/260	2.3	1.1 to 4.7	2.6	1.2 to 5.5
RF to RA	University degree†	12/75	1.0	–	1.0	–

Total RA	No university degree	242/260	2.2	1.4 to 3.4	2.2	1.3 to 3.6
	University degree†	34/75	1.0	–	1.0	to


		Ca/Co	RR§	95% CI	RR§§	95% CI
Values are relative risks with 95% confidence intervals.
*Relative risk adjusted for age and residential area.
**Relative risk adjusted for age, residential area, and smoking.
§Relative risk adjusted for age, residential area, and sex.
§§Relative risk 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.
All
RF+ RA	No university degree	502/844	1.6	1.3 to 2.1	1.7	1.2 to 2.2
RF+ RA	University degree†	104/279	1.0	–	1.0	–

RF− RA	No university degree	250/844	1.2	0.8 to 1.6	1.1	0.8 to 1.6
RF− RA	University degree†	73/279	1.0	–	1.0	–

Total RA	No university degree	752/844	1.4	1.2 to 1.8	1.5	1.1 to 1.9
Total RA	University degree†	177/279	1.0	–	1.0	–