Table 1.
Sample characteristics and stratification by participants’ rheumatoid arthritis status.
| Rheumatoid arthritis | |||
|---|---|---|---|
| No (N = 3 956, 95.4%) | Yes (N = 236, 4.6%) | p-value | |
| Age (mean years, 95% CI) | 43.40 (41.57, 45.23) | 56.53 (54.42, 58.64) | < 0.001 |
| Men (n, %) | 2080 (50.8) | 93 (39.2) | 0.015 |
| Race/ethnicity (n, %) | 0.008 | ||
| Non-Hispanic White | 1329 (63.7) | 78 (66.7) | |
| Mexican American | 423 (8.7) | 22 (6.7) | |
| Other Hispanic | 402 (7.0) | 23 (5.5) | |
| Non-Hispanic Black | 1012 (11.8) | 91 (16.4) | |
| Other race | 790 (8.8) | 22 (4.8) | |
| Missing data | 0 (0.0) | 0 (0.0) | |
| Education (n, %) | 0.001 | ||
| <9th grade | 309 (4.8) | 36 (11.3) | |
| 9–11th grade | 529 (10.2) | 39 (14.1) | |
| High school graduate/GED | 820 (19.6) | 53 (25.1) | |
| Some college or AA degree | 1189 (32.0) | 80 (35.5) | |
| College graduate or above | 1108 (33.4) | 26 (14.1) | |
| Missing data | 0 (0.0) | 0 (0.0) | |
| Annual family income (n, %) | 0.043 | ||
| < $35 000 | 1715 (34.4) | 139 (49.2) | |
| $35 000–$75 000 | 1011 (28.8) | 45 (25.7) | |
| > $75 000 | 940 (31.7) | 32 (19.9) | |
| Missing data | 290 (5.1) | 20 (5.2) | |
| Smoking (n, %) | 0.099 | ||
| Never smoker | 2407 (59.6) | 117 (45.5) | |
| Former smoker | 755 (20.9) | 66 (26.7) | |
| Current smoker | 788 (19.4) | 53 (27.9) | |
| Missing data | 6 (0.1) | 0 (0.0) | |
| Alcohol drinking (n, %) | 0.111 | ||
| Lifetime abstainer | 493 (9.0) | 39 (10.4) | |
| Former drinker | 384 (7.8) | 35 (11.5) | |
| Current drinker | 2571 (72.9) | 145 (72.8) | |
| Missing data | 508 (10.4) | 17 (5.3) | |
| BMI (mean kg/m2, 95% CI) | 28.23 (27.82, 28.65) | 29.97 (28.69, 31.24) | 0.005 |
| Very loud noise exposure (n, %) | < 0.001 | ||
| Never | 2903 (74.1) | 119 (52.7) | |
| < 5 years | 381 (11.1) | 19 (7.9) | |
| 5–9 years | 104 (2.7) | 9 (2.6) | |
| 10–14 years | 76 (1.8) | 5 (2.2) | |
| ≥ 15 years | 140 (3.5) | 18 (14.4) | |
| Missing data | 352 (6.7) | 66 (20.2) | |
| Mineral dust exposure (n, %) | 0.116 | ||
| Never | 2683 (69.0) | 145 (64.0) | |
| ≤ 5 years | 453 (12.31) | 24 (9.7) | |
| 6–10 years | 185 (1.2) | 11 (3.3) | |
| 11–15 years | 116 (3.0) | 5 (2.8) | |
| > 15 years | 203 (6.0) | 17 (10.5) | |
| Missing data | 316 (5.4) | 34 (9.7) | |
| Organic dust exposure (n, %) | 0.002 | ||
| Never | 2987 (76.4) | 145 (60.7) | |
| ≤ 5 years | 338 (9.3) | 22 (12.3) | |
| 6–10 years | 113 (3.0) | 14 (6.7) | |
| 11–15 years | 65 (1.9) | 5 (1.8) | |
| > 15 years | 142 (4.1) | 17 (9.1) | |
| Missing data | 311 (5.3) | 33 (9.5) | |
| Exhaust fumes exposure (n, %) | < 0.001 | ||
| Never | 2892 (74.9) | 145 (58.8) | |
| ≤ 5 years | 346 (9.5) | 18 (9.8) | |
| 6–10 years | 157 (3.9) | 14 (4.2) | |
| 11–15 years | 84 (2.21) | 5 (3.3) | |
| > 15 years | 166 (4.2) | 21 (14.4) | |
| Missing data | 311 (5.2) | 33 (9.5) | |
| Other fumes exposure (n, %) | 0.013 | ||
| Never | 2683 (69.4) | 130 (59.5) | |
| ≤ 5 years | 481 (12.9) | 23 (10.4) | |
| 6–10 years | 195 (4.7) | 9 (3.6) | |
| 11–15 years | 91 (2.4) | 10 (3.6) | |
| > 15 years | 196 (5.3) | 31 (13.3) | |
| Missing data | 310 (5.2) | 33 (9.5) | |
Data source: CDC/NCHS – NHANES, 2011 – 2012.
Reported coefficients (except raw number of cases) are weighted to obtain nationally representative estimates. The “Interview weight” is applied to all univariate tests except for that involving body mass index (BMI), for which the “Interview and MEC Exam weight” is used.
Percentages are reported within columns.
p-values are associated with Pearson chi-square test, ANOVA, or t-test.