Baseline characteristics*
| HUNT 2 | HUNT 3 | |||||
| RA (n=307) | Controls (n=53 258) | RA versus controls, p value | RA (n=41) | Controls (n=7680) | RA versus controls, p value | |
| Female sex, n (%) | 206 (67) | 27 303 (51) | <0.001 | 29 (71) | 4426 (58) | 0.090 |
| Age (years), mean (SD) | 56.3 (12.0) | 47.6 (16.1) | <0.001 | 65.0 (14.2) | 43.7 (17.3) | <0.001 |
| Systolic blood pressure (mm Hg), mean (SD) | 138 (20) | 136 (21) | 0.23 | 142 (20) | 126 (17) | <0.001 |
| Body mass index (kg/m2), mean (SD) | 26.5 (4.1) | 26.2 (4.0) | 0.15 | 29.0 (5.2) | 26.6 (4.6) | 0.041 |
| eCRF-dichotomous | <0.001 | <0.001 | ||||
| Below median, n (%) | 223 (72.6) | 26 385 (49.5) | 34 (82.9) | 3660 (47.7) | ||
| Above median, n (%) | 84 (27.4) | 26 873 (50.5) | 7 (17.1) | 4020 (52.3) | ||
| eCRF-tertiles | <0.001 | <0.001 | ||||
| Lower tertile, n (%) | 181 (59.0) | 17 488 (32.8) | 31 (75.6) | 2449 (31.9) | ||
| Middle tertile, n (%) | 69 (22.5) | 17 851 (33.5) | 6 (14.6) | 2525 (32.9) | ||
| Higher tertile, n (%) | 57 (18.6) | 17 919 (33.7) | 4 (9.8) | 2706 (35.2) | ||
| eCRF-continuous (mL/(min x kg)), mean (SD) | 32.4 (9.2) | 40.2 (9.0) | <0.001 | 24.7 (8.7) | 38.5 (9.1) | <0.001 |
| Creatinine (µmol/L), mean (SD) | 85 (13) | 88 (15) | 0.004 | 85 (22) | 82 (15) | 0.13 |
| Total cholesterol (mmol /L), mean (SD) | 6.0 (1.2) | 5.8 (1.2) | 0.014 | 5.6 (1.0) | 5.2 (1.1) | 0.031 |
| Smoking | <0.001 | 0.42 | ||||
| Never, n (%) | 107 (34.9) | 23 955 (45.3) | 18 (43.9) | 4157 (54.1) | ||
| Previous, n (%) | 107 (34.9) | 12 782 (24.2) | 13 (31.7) | 1977 (25.7) | ||
| Present, n (%) | 93 (30.3) | 16 119 (30.5) | 10 (24.4) | 1546 (20.1) | ||
| Previous cardiovascular disease, n (%) | 30 (9.8) | 3348 (6.3) | 0.010 | 9 (22) | 395 (5.1) | <0.001 |
| Hypertension, n (%) | 155 (50.5) | 21 244 (39.9) | <0.001 | 28 (68.3) | 2015 (26.2) | <0.001 |
| Diabetes, n (%) | 13 (4.2) | 1402 (2.6) | 0.14 | 3 (7.3) | 280 (3.7) | 0.008 |
Hypertension: systolic blood pressure ≥140 mm Hg and/or a diastolic blood pressure ≥90 mm Hg and/or the use of antihypertensive medication. Previous cardiovascular disease: self-reported stroke and/or angina and/or myocardial infarction. Diabetes: self-reported diabetes and/or the use of antidiabetic medication and/or having a non-fasting blood-glucose level>11 mmol/L. eCRF, estimated cardiorespiratory fitness; eCRF-continuous, eCRF as a continuous variable; eCRF-dichotomous, eCRF categorised as above or below the median eCRF for each participant’s sex and age group (<40 years, 40–59 years ≥60 years); eCRF-tertiles, eCRF categorised into higher, middle and lower eCRF tertile for each participant’s sex and age group.
*There were no missing data in patients with RA. Missingness for controls, HUNT2: hypertension 0.03%, smoking 0.08%, body mass index 0.002%, systolic blood pressure 0.01%; HUNT3: systolic blood pressure 0.9%. Comparisons between patients with RA and controls were performed using the χ2 test or t-test.
eCRF, estimated cardiorespiratory fitness; HUNT2 and HUNT3, The second and third wave of the longitudinal population-based Trøndelag Health study; RA, rheumatoid arthritis.