Table 1.
Baseline characteristics collected from Finnish patients via questionnaire in 1997
| No asthma, n (%) | Asthma, n (%) | Missing (%) | |
| Sex | |||
| Men | 912 (38.0) | 532 (38.2) | |
| Women | 1486 (62.0) | 862 (61.8) | |
| Total | 2398 | 1394 | |
| Age at baseline (in years) | |||
| ≤59 | 1506 (62.8) | 893 (64.1) | |
| 60–69 | 699 (29.1) | 401 (28.8) | |
| 70–79 | 166 (6.9) | 84 (6.0) | |
| ≥80 | 27 (1.1) | 16 (1.1) | |
| Pack-years | 6.7 | ||
| 0 | 1286 (57.1) | 625 (48.6) | |
| ≤19 | 595 (26.4) | 389 (30.2) | |
| ≥20 | 371 (16.5) | 273 (21.2) | |
| BMI (kg x m -2) | 2.4 | ||
| Underweight (<18.5) | 26 (1.1) | 19 (1.4) | |
| Normal (18.5–24.99) | 998 (42.6) | 463 (34.0) | |
| Overweight (25–29.99) | 958 (40.9) | 577 (42.4) | |
| Obese (≥30) | 358 (15.3) | 303 (22.2) | |
| Education level | 2.2 | ||
| Matriculation exam | 435 (18.5) | 187 (13.8) | |
| Secondary school | 560 (23.8) | 322 (23.7) | |
| Primary school or less | 1356 (57.7) | 850 (62.5) | |
Lifetime tobacco exposure was calculated in pack-years (number of cigarettes per day/20×number of years smoked, where 1 pipe=2.5 cigarettes and 1 cigar=4 cigarettes) on which individuals were divided into three groups: 0, ≤19 and ≥20 pack-years.
BMI assessed as weight in kilograms divided by the square of the height in metres, then divided into four categories according to WHO classification.
Level of education was obtained through a questionnaire and categorised based on the Finnish education system: matriculation examination (13 years, reference value), secondary school or equivalent (9 years) and primary school or less (≤6 years).
BMI, body mass index.