Baseline characteristics of the three cohorts
| Demographics | Cohort 1 (n = 374) | Cohort 2 (n = 363) | Cohort 3 (n = 377) |
|---|---|---|---|
| Differences in the cohorts at baseline are accounted for using regression analyses for the comparisons of interest. | |||
| Age (in years, mean) | 6.1 | 6.0 | 5.9 |
| % | % | % | |
| Sex (male) | 63.1 | 62.8 | 61.0 |
| Asthma severity | |||
| Persistent asthma | 49.7 | 44.2 | 38.9 |
| Frequent episodic asthma | 15.8 | 13.0 | 12.0 |
| Infrequent episodic asthma | 34.5 | 42.8 | 49.1 |
| Attacks in past 12 months | |||
| No attacks | 21.8 | 19.7 | 30.8 |
| 1–3 attacks | 37.6 | 45.5 | 40.5 |
| 4–12 attacks | 32.5 | 27.2 | 23.6 |
| >12 attacks | 8.1 | 7.6 | 5.1 |
| Admissions to hospital in past 12 months | |||
| No admissions | 71.1 | 72.0 | 80.8 |
| 1–3 admissions | 27.0 | 26.3 | 17.8 |
| 4–12 admissions | 1.9 | 1.7 | 1.4 |