Baseline characteristics at screening in females in different body mass index(BMI) groups and in those who were and were not incident asthma cases
| <20 | 20–24.9 | 25–29.9 | 30–34.9 | ≥35 | ptrend# | Incident asthma¶ | ||
| No | Yes | |||||||
| Subjects n | 3493 | 34688 | 18559 | 4688 | 1355 | 60181 | 2602 | |
| ΔBMI kg·m−2 | 1.5 | 2.1 | 3.2 | 4.7 | 6.5 | <0.001 | 2.6 | 3.3 |
| ΔBMI % | 8.0 | 9.2 | 11.9 | 14.8 | 16.9 | <0.001 | 10.4 | 12.5 |
| Year of birth | 1955.5 | 1955.6 | 1955.6 | 1955.8 | 1955.9 | <0.001 | 1955.6 | 1955.5 |
| Never-smokers | 35.9 | 36.9 | 38.1 | 40.1 | 43.6 | <0.001 | 38.0 | 27.4 |
| Ex-smokers | 13.8 | 24.1 | 26.3 | 26.0 | 26.7 | <0.001 | 24.5 | 20.4 |
| Current smokers | 50.3 | 39.0 | 35.6 | 33.9 | 29.7 | <0.001 | 37.5 | 52.2 |
| High education+ | 33.3 | 33.6 | 27.7 | 22.1 | 19.6 | <0.001 | 30.9 | 24.8 |
| Physically active§ | 9.0 | 10.7 | 9.3 | 7.6 | 4.7 | <0.001 | 9.8 | 9.7 |
| Disability pension | 5.4 | 3.5 | 4.9 | 7.1 | 11.4 | <0.001 | 4.2 | 9.3 |
| Urban residence | 19.9 | 18.2 | 15.7 | 14.2 | 12.3 | <0.001 | 17.2 | 15.1 |
Data are presented as means for continuous variables and percentages for dichotomous variables; BMI group ranges are shown in kilogrammes per metre squared. ptrend: p-value for trend; Δ: change. #: calculated for subjects with a BMI of ≥20 kg·m−2; ¶: received at least two prescriptions of reimbursed inhaled anti-asthmatic drugs during 2004–2007, with the last one being dispensed ≥6 months after the first one; +: university/college or higher (level 4 or 5); §: ≥3 h·week−1 with hard activity (level 3).