Table 1. Baseline Characteristics of Study Participants.
| Characteristic | Total | RA status | Serologic status of RA | ||||
|---|---|---|---|---|---|---|---|
| No | Yes | P value | SNRA | SPRA | P value | ||
| Participants, No. | 230 922 | 192 435 | 38 487 | NA | 11 645 | 26 842 | NA |
| Age, mean (SD), y | 54.6 (12.1) | 54.6 (12.1) | 54.6 (12.1) | NA | 52.3 (12.8) | 55.6 (11.6) | NA |
| 20-39 | 23 550 (10.2) | 19 625 (10.2) | 3925 (10.2) | >.99 | 1905 (16.4) | 2020 (7.5) | <.001 |
| 40-59 | 127 242 (55.1) | 106 035 (55.1) | 21 207 (55.1) | 6336 (54.4) | 14 871 (55.4) | ||
| ≥60 | 80 130 (34.7) | 66 775 (34.7) | 13 355 (34.7) | 3404 (29.2) | 9951 (37.1) | ||
| Sex | |||||||
| Male | 66 996 (29.0) | 55 830 (29.0) | 11 166 (29.0) | >.99 | 3928 (33.7) | 7238 (27.0) | <.001 |
| Female | 163 926 (71.0) | 136 605 (71.0) | 27 321 (71.0) | 7717 (66.3) | 19 604 (73.0) | ||
| Income | |||||||
| Low ≥25% Medicaid group | 51 583 (22.3) | 43 205 (22.5) | 8378 (21.8) | .003 | 2306 (19.8) | 6072 (22.6) | <.001 |
| Smoking status | |||||||
| Never or former smoking | 201 349 (87.2) | 167 750 (87.2) | 33 599 (87.2) | .50 | NA | NA | .97 |
| Current smoking | 29 573 (12.8) | 24, 685 (12.8) | 4888 (12.7) | 1, 480 (12.7) | 3408 (12.7) | ||
| Alcohol consumption | |||||||
| None | 152 973 (66.2) | 125 642 (65.3) | 27 331 (71.0) | <.001 | NA | NA | <.001 |
| >0 g/d | 77 949 (33.8) | 66 793 (34.7) | 11 156 (29.0) | 3835 (32.9) | 7321 (27.3) | ||
| Physical activity | |||||||
| None | 185 542 (80.3) | 153 906 (80.0) | 31 636 (82.2) | <.001 | NA | NA | .008 |
| Regular | 45 380 (19.7) | 38 529 (20.0) | 6851 (17.8) | 2165 (18.6) | 4686 (17.5) | ||
| BMI | |||||||
| <25 | 158 212 (68.5) | 130 665 (67.9) | 27 547 (71.6) | <.001 | NA | NA | <.001 |
| ≥25 | 72 710 (31.5) | 61 770 (32.1) | 10 940 (28.4) | 3582 (30.8) | 7358 (27.4) | ||
| Diabetes | 25 438 (11.02) | 21 356 (11.1) | 4082 (10.6) | .005 | 1233 (10.6) | 2849 (10.6) | .94 |
| Hypertension | 75 246 (32.6) | 61 785 (32.1) | 13 461 (35.0) | <.001 | 4206 (36.1) | 9255 (34.5) | .002 |
| Dyslipidemia | 63 066 (27.3) | 52 660 (27.4) | 10 406 (27.0) | .19 | 3324 (28.5) | 7082 (26.4) | <.001 |
| Chronic kidney disease | 12 971 (5.6) | 10 270 (5.3) | 2701 (7.0) | <.001 | 895 (7.7) | 1806 (6.7) | .001 |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); NA, not applicable; SNRA, seronegative rheumatoid arthritis; SPRA, seropositive rheumatoid arthritis.