Characteristics of the Diet, Cancer and Health cohort (n=53 695) by first asthma hospitalisation status at follow-up for full cohort
| Total n=53 695 | No asthma n=52 698 | Asthma n=997 | HR* (95%CI) | |
| Baseline cohort covariates | ||||
| Mean (SD) age (years) | 56.7 (4.4) | 56.7 (4.4) | 57.3 (4.5) | 1.04 (1.02 to 1.05) |
| Males n (%) | 25 575 (47.6) | 25 190 (47.8) | 385 (38.6) | 0.71 (0.62 to 0.80) |
| Never smoked n (%) | 18 986 (35.4) | 18 677 (35.4) | 309 (31.0) | 1.00 |
| Previously smoked n (%) | 15 362 (28.6) | 15 044 (28.5) | 318 (31.9) | 1.30 (1.11 to 1.52) |
| Currently smoke n (%) | 19 347 (36.0) | 18 977 (36.0) | 370 (37.1) | 1.19 (1.02 to 1.38) |
| Mean (SD) smoking duration (years) | 19.0 (17.2) | 19.0 (17.2) | 21.3 (17.4) | 1.08 (1.05 to 1.12) |
| Mean (SD) smoking intensity (g/day) | 6.3 (10.4) | 6.3 (10.4) | 6.0 (9.6) | 1.00 (0.99 to 1.00) |
| Environmental tobacco smoke n (%) | 34 527 (64.3) | 33 841 (64.2) | 686 (68.8) | 1.21 (1.06 to 1.38) |
| Occupational exposure n (%) | 19 502 (36.3) | 19 105 (36.2) | 397 (39.8) | 1.15 (1.01 to 1.32) |
| Obese (BMI ≥30 kg/m2) n (%) | 7808 (14.5) | 7627 (14.5) | 181 (18.1) | 1.31 (1.11 to 1.53) |
| <8 years of education n (%) | 17 763 (33.1) | 17 393 (33.0) | 370 (37.1) | 1.00 |
| 8–10 years of education n (%) | 24 768 (46.1) | 24 325 (46.2) | 443 (44.4) | 0.86 (0.75 to 0.99) |
| ≥10 years of education n (%) | 11 164 (20.8) | 10 980 (20.8) | 184 (18.5) | 0.80 (0.67 to 0.95) |
| Mean (SD) fruit intake (g/day) | 182 (149) | 181 (149) | 184 (145) | 1.00 (0.99 to 1.01) |
| Asthma before baseline n (%) | 552 (1.0) | 376 (0.7) | 176 (17.6) | 25.6 (21.7 to 30.2) |
| Comorbid conditions (ICD-10 code†) | ||||
| COPD (J40–44) n (%) | 2135 (4.0%) | 1920 (3.6%) | 215 (21.5%) | 6.96 (6.00 to 8.09) |
| Ischaemic heart disease (I20–25) n (%) | 5457 (10.2%) | 5362 (10.2%) | 95 (9.5%) | 0.94 (0.76 to 1.16) |
| Stroke (I60–I63) n (%) | 2542 (4.7%) | 2520 (4.8%) | 22 (2.2%) | 0.46 (0.30 to 0.69) |
| Diabetes‡ n (%) | 5340 (9.9%) | 5213 (9.9%) | 127 (12.7%) | 1.30 (1.08 to 1.57) |
* Cox proportional hazards model univariate effect of each covariate/comorbid condition in ‘Asthma’ versus ‘No asthma’ columns.
† For comorbid conditions identified in the Danish Hospital Discharge register as hospitalisations prior to asthma hospitalisation.
‡ Identified in the Danish Diabetes Register.
BMI, body mass index; COPD, chronic obstructive pulmonary disease.