Characteristics of study population
| Characteristics | Number of positivity, n (%) |
|---|---|
| *Positive skin test responses to one or more common aeroallergens. | |
| Mean (range) age (years) | 14.6 (10–18) |
| Male | 1004 (48.9) |
| Atopy* | 767 (37.3) |
| History of passive smoking | 1342 (65.3) |
| Family history of allergic disease | 376 (18.3) |
| Vaccination history | 1552 (75.5) |