Table 1 Patient characteristics in the whole cohort (non‐participants and participants) and in the extensive smoking questionnaire group.
| All (n = 336) | Dead at the time of the questionnaire (n = 25; 7%) | Non‐participants* (n = 73; 22%) | Participants (n = 238; 71%) | Smoking questionnaire responders (n = 210; 63%) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cases (RN) | 112 | 14 (12%) | 22 (20%) | 76 (68%) | 64 (57%) | |||||
| Controls | 224 | 11 (5%) | 51 (23%) | 162 (72%) | 146 (65%) | |||||
| Men | 174 (52%) | 18 (72%) | 37 (51%) | 119 (50%) | 108 (51%) | |||||
| Women | 162 (48%) | 7 (28%) | 36 (49%) | 119 (50%) | 102 (49%) | |||||
| Age (years) | 56 (14) | 67 (13) | 55 (17) | 56 (13) | 56 (12) | |||||
| RA duration (months) | 6.3 (3.4) | 5.2 (2.8) | 6.1 (3.6) | 6.5 (3.4) | 6.6 (3.3) | |||||
| DAS28 | 5.18 (1.49) | 4.99 (1.04) | 5.14 (1.15) | 5.15 (1.35) | 5.18 (1.34) | |||||
| HAQ | 0.97 (0.64) | 1.19 (0.74) | 1.01 (0.59) | 0.94 (0.64) | 0.94 (0.62) | |||||
| RF+ | 220 (65%) | 14 (56%) | 45 (62%) | 161 (68%) | 143 (68%) | |||||
| Smoking data | ||||||||||
| Ever smoked | 222 (66%) | 18 (72%) | 43 (59%) | 161 (68%) | 141 (67%) | |||||
| Current smokers | 118 (35%) | 10 (40%) | 25 (34%) | 83 (35%) | 70 (33%) | |||||
| Former smokers | 104 (31%) | 8 (32%) | 18 (25%) | 78 (33%) | 71 (34%) | |||||
| Never smoked | 69 (21%) | 0 | 0 | 69 (29%) | 69 (33%) | |||||
| Missing data | 45 (13%) | 7 (28%) | 30 (41%) | 8 (3%) | 0 |
Values are mean (SD) or n (%).
*Includes patients who moved abroad, n = 3, and who refused to participate, n = 2
DAS28, 28 joint disease activity score; HAQ, Health Assessment Questionnaire; RA, rheumatoid arthritis; RF+, rheumatoid factor positive; RN, rheumatoid nodules.