Table 1.
Characteristics of NHANES Participants from 2003 to 2016
| Characteristics | Total | Non-Rheumatoid Arthritis | Rheumatoid Arthritis | P value |
|---|---|---|---|---|
| Overall | 14539 | 13,694 (95.6) | 845 (4.4) | |
| Age | <0.001 | |||
| <40 | 5183 (36.6) | 5103 (37.8) | 80 (10.8) | |
| ≥40 | 9356 (63.4) | 8591 (62.2) | 765 (89.2) | |
| Race | <0.001 | |||
| Mexican American | 2356 (7.8) | 2231 (7.9) | 125 (6.0) | |
| Other Hispanic | 1290 (4.8) | 1204 (4.7) | 86 (5.7) | |
| Non-Hispanic White | 6777 (69.8) | 6428 (70.1) | 349 (65.0) | |
| Non-Hispanic Black | 2972 (11.4) | 2722 (11.0) | 250 (18.4) | |
| Other race | 1144 (6.3) | 1109 (6.3) | 35 (4.9) | |
| PIR | <0.001 | |||
| ≤1.3 | 4800 (23.4) | 4415 (22.9) | 385 (35.5) | |
| 1.3–3.5 | 5455 (36.2) | 5154 (36.1) | 301 (39.0) | |
| >3.5 | 4284 (40.4) | 4125 (41.1) | 159 (25.5) | |
| Education | <0.001 | |||
| Did not graduate from high school | 3508 (16.5) | 3216 (16.1) | 292 (26.0) | |
| Graduated from high school | 3372 (22.7) | 3171 (22.6) | 201 (26.3) | |
| College education or above | 7659 (60.8) | 7307 (61.4) | 352 (47.7) | |
| BMI (kg/m2) | <0.001 | |||
| <25 | 4454 (35.0) | 4282 (35.4) | 172 (25.8) | |
| 25–30 | 4157 (28.0) | 3930 (28.1) | 227 (25.8) | |
| ≥30 | 5928 (37.0) | 5482 (36.5) | 446 (48.4) | |
| Smoking | <0.001 | |||
| Never smoking | 9109 (59.7) | 8660 (60.3) | 449 (46.5) | |
| Former smoking | 2861 (21.0) | 2663 (20.9) | 198 (23.3) | |
| Now Smoking | 2569 (19.3) | 2371 (18.8) | 198 (30.2) | |
| Alcohol drinking | 0.002 | |||
| No | 5802 (32.2) | 5412 (31.8) | 390 (39.8) | |
| Yes | 8737 (67.8) | 8282 (68.2) | 455 (60.2) | |
| Diabetes | <0.001 | |||
| No | 12416 (89.1) | 11,818 (89.7) | 598 (76.0) | |
| Yes | 2123 (10.9) | 1876 (10.3) | 247 (24.0) | |
| Hypertension | <0.001 | |||
| No | 7403 (54.6) | 7167 (55.6) | 236 (32.9) | |
| Yes | 7136 (45.4) | 6527 (44.4) | 609 (67.1) | |
| White blood cell (103/μL) | 7.39 (2.30) | 7.39 (2.30) | 7.49 (2.37) | 0.431 |
| Red blood cell (106/μL) | 4.45 (0.40) | 4.45 (0.39) | 4.40 (0.42) | 0.011 |
| MPV (fL) | 8.17 (0.94) | 8.17 (0.94) | 8.17 (0.96) | 0.869 |
| SII | 580.20 (339.20) | 578.22 (333.70) | 622.90 (439.60) | 0.060 |
| Energy (Kcal) | 1789.65 (625.47) | 1796.47 (625.75) | 1642.81 (601.22) | <0.001 |
| Dietary niacin intake (mg/d) | 21.12 (9.32) | 21.22 (9.35) | 18.90 (8.29) | <0.001 |