Table 1 Baseline characteristics of the study participants in the UK Biobank
Characteristics | Normal (n = 144,350) | Incident RA (n = 675) | P value |
|---|---|---|---|
Age, mean (SD) | 56.47 (7.83) | 59.65 (7.16) | <0.001 |
Sex, n (%) | Â | Â | <0.001 |
 Female | 72,844 (50.5) | 444 (65.8) |  |
 Male | 71,506 (49.5) | 231 (34.2) |  |
BMI, mean (SD) | 26.88 (4.40) | 27.48 (5.08) | <0.001 |
 Missing, n (%) | 281 (0.2) | 2 (0.3) |  |
TDI, mean (SD) | −1.79 (2.81) | −1.51 (2.78) | 0.011 |
 Missing, n (%) | 172 (0.1) | 0 (0.0) |  |
Healthy diet score, median [IQR] | 3.00 [2.00, 4.00] | 3.00 [2.00, 4.00] | 0.622 |
TPA group, n (%) | Â | Â | 0.109 |
 Low | 6,680 (4.6) | 40 (5.9) |  |
 Moderate | 14,725 (10.2) | 63 (9.3) |  |
 High | 98,487 (68.2) | 417 (61.8) |  |
 Missing | 24,458 (16.9) | 155(23.0) |  |
RDW group, n (%) | Â | Â | <0.001 |
 Q1 (10.78–12.89) | 36,013 (24.9) | 105 (15.6) |  |
 Q2 (12.89–13.30) | 35,481 (24.6) | 131 (19.4) |  |
 Q3 (13.30–13.80) | 37,704 (26.1) | 152 (22.5) |  |
 Q4 (>13.80) | 35,152 (24.4) | 287 (42.5) |  |
Alcohol status, n (%) | Â | Â | 0.001 |
 Never | 3,872 (2.7) | 27 (4.0) |  |
 Previous | 3,323 (2.3) | 27 (4.0) |  |
 Current | 137,075 (95.0) | 621 (92.0) |  |
 Missing | 80 (0.0) | 0 (0.0) |  |
Smoking status, n (%) | Â | Â | <0.001 |
 Never | 84,127 (58.3) | 305 (45.2) |  |
 Previous | 46,928 (32.5) | 262 (38.8) |  |
 Current | 12,908 (8.9) | 102 (15.1) |  |
 Missing | 387 (0.0) | 6 (0.9) |  |
Prevalent hypertension, n (%) | Â | Â | <0.001 |
 No | 112,341 (77.8) | 478 (70.8) |  |
 Yes | 32,009 (22.2) | 197 (29.2) |  |
Hb, median [IQR] | 14.29 [13.44, 15.12] | 13.73 [12.96, 14.59] | <0.001 |
 Missing, n (%) | 1 (0.0) | 0 (0.0) |  |
CRP, median [IQR] | 1.17 [0.60, 2.35] | 2.37 [1.18, 5.43] | <0.001 |
 Missing, n (%) | 6061 (4.2) | 26 (3.9) |  |
Genetic risk category, n (%) | Â | Â | <0.001 |
 Low | 28,929 (20.0) | 73 (10.8) |  |
 Intermediate | 86,650 (60.0) | 368 (54.5) |  |
 High | 28,771 (19.9) | 234 (34.7) |  |