Table 1

Characteristics of patients with and without rheumatoid arthritis on 1 January 2015

RA
(N=1643)
Non-RA
(N=1643)
P value
Age, years, mean (SD)63.1 (14.5)63.1 (14.5)0.98
Female sex1176 (72%)1176 (72%)1.00
Race/ethnicity0.49
Missing08
White1508 (92%)1484 (91%)
Hispanic59 (4%)62 (4%)
Black24 (2%)28 (2%)
Asian36 (2%)34 (2%)
Other/mixed16 (1%)27 (2%)
County of residence1.00
Olmsted, MN907 (55%)907 (55%)
Dodge, MN83 (5%)83 (5%)
Freeborn, MN103 (6%)103 (6%)
Goodhue, MN123 (7%)123 (7%)
Mower, MN212 (13%)212 (13%)
Steele, MN101 (6%)101 (6%)
Wabasha, MN68 (4%)68 (4%)
Waseca, MN46 (3%)46 (3%)
History of smoking0.029
Missing23191
Any history of smoking886 (55%)737 (51%)
Body mass index (kg/m2), mean (SD)29.8 (7.2)29.9 (6.9)0.53
Missing70178
RA disease duration, years, median (IQR)*6.5 (3.1–13.8)------
Missing506
Length of medical history, years35.8 (19.1)33.5 (19.9)0.001
Length of lookback (years)<0.001
Mean (SD)4.9 (0.5)4.8 (0.8)
Range0.04–5.00.01–5.0
Length of lookback<0.001
Less than 5 years71 (4.3%)155 (9.4%)
5 years1572 (95.7%)1488 (90.6%)
  • *RA disease duration was unavailable for those who moved into the geographic area with previously diagnosed RA.

  • RA, rheumatoid arthritis.