Baseline characteristics of the study sample from the BRASS cohort by smoking status. Total sample size was 659 after 3 patients were excluded for lack of smoking status.
| Smoking Status | ||||
|---|---|---|---|---|
| Characteristics | Never, n = 353 | Past, n = 250 | Current, n = 56 | p |
| Age, yrs, mean ± SD | 54.6 ± 14.3 | 61.2 ± 11.0 | 54.5 ± 11.4 | < 0.001 |
| Sex (female), % | 83.0 | 82.4 | 78.6 | 0.72 |
| Race (white), % | 93.1 | 97.2 | 89.1 | 0.02 |
| Education (high school graduate or higher), % | 67.3 | 57.3 | 55.4 | 0.02 |
| Smoking pack-yrs | 0 | 19.2 ± 21.4 | 29.6 ± 22.1 | < 0.001 |
| Alcohol consumption, g/day | 4.8 ± 10.1 | 7.7 ± 14.9 | 6.2 ± 11.1 | 0.02 |
| DAS28-CRP3 | 3.97 ± 1.56 | 4.07 ± 1.50 | 4.45 ± 1.48 | 0.06 |
| MHAQ | 0.41 ± 0.45 | 0.40 ± 0.46 | 0.56 ± 0.53 | 0.13 |
| Disease duration, yrs | 14.8 ± 12.2 | 15.7 ± 12.2 | 14.9 ± 12.3 | 0.63 |
| HLA-SE carrier, % | 61.5 | 66.0 | 67.9 | 0.42 |
| BMI, kg/m2, mean ± SD | 26.2 ± 5.6 | 27.3 ± 5.2 | 26.9 ± 6.1 | 0.004 |
| Anti-CCP–positive, % | 64.4 | 71.8 | 71.7 | 0.13 |
| Prednisone, % | 29.7 | 30.0 | 30.4 | 0.99 |
| Methotrexate, % | 47.0 | 52.0 | 42.9 | 0.33 |
| Antimalarial, % | 17.6 | 14.0 | 16.1 | 0.50 |
| Other DMARD, % | 17.6 | 19.2 | 19.6 | 0.85 |
| Biologic DMARD, % | 37.7 | 40.8 | 35.7 | 0.66 |
| NSAID, % | 63.5 | 63.2 | 66.1 | 0.92 |
Some measurements were missing at baseline (race, n = 653; education, n = 656; and anti-CCP, n = 649). P values were based on Kruskal-Wallis test for continuous variables or chi-squared test for categorical variables. DAS28-CRP3: Disease Activity Score using 28 joints with high-sensitivity C-reactive protein; MHAQ: Modified Health Assessment Questionnaire; BMI: body mass index; DMARD: disease-modifying antirheumatic drug (biologic DMARD refers to all kinds of anti-tumor necrosis factor, anti-interleukin 1, or anti-B cell agents); NSAID: nonsteroidal antiinflammatory drug; anti-CCP: anticyclic citrullinated peptide.