Table 1 Demographic data for cases with rheumatoid arthritis and controls.

Characteristic	Cases [n]	Controls [n]
Median (IQR) age of disease onset* (years)	44 (32, 57) [1418]	48 (48, 48) [2440]
Proportion of females (%)	67 [977/1455]	52 [1360/2636]
Proportion seropositive for RF (%)	79 [1101/1394]	–
Proportion with erosive disease (%)	68 [767/1135]	–
Proportion positive for SE (1 and/or 2 copies) (%)	80 [862/1082]	46 [798/1722]
Total subjects available	1469	2760

IQR, interquartile range; RF, rheumatoid factor; SE, shared epitope.

*For non‐1958 birth cohort controls, age when bled was used.