| Children aged 7-8 | Children aged 13-14 | ||||
---|---|---|---|---|---|---|
Participant characteristics | G/C | T/C | p†| G/C | T/C | p†|
(expressed as percentages) | (n = 2216) | (n = 2353) | (n = 2452) | (n = 3135) | ||
Female gender (%) | 49.5 | 50.6 | Â | 48.2 | 51.7 | Â |
Parental education (%) | Â | Â | Â | Â | Â | Â |
  Only one secondary education | 5.3 | 49.9 |  | 13.0 | 43.0 |  |
  Both secondary education | 40.9 | 30.3 |  | 46.7 | 36.8 |  |
  Only one tertiary education | 24.1 | 12.8 |  | 21.2 | 11.6 |  |
  Both tertiary education | 29.8 | 7.1 | * | 19.0 | 8.6 | * |
Area of residence (%) | Â | Â | Â | Â | Â | Â |
  Urban | 66.5 | 40.9 |  | 65.9 | 46.5 |  |
  Sub-rural | 21.0 | 24.3 |  | 18.2 | 22.1 |  |
  Rural | 12.5 | 34.8 | * | 15.9 | 31.4 | * |
Family history of allergies (%) | 37.0 | 19.5 | * | 16.5 | 10.9 | * |
Older siblings (%) | Â | Â | Â | Â | Â | Â |
  None | 38.7 | 50.8 |  | 26.3 | 44.4 |  |
  1 | 34.3 | 34.3 |  | 37.8 | 34.4 |  |
  ≥2 | 27.0 | 14.9 | * | 35.9 | 21.2 | * |
Passive smoking (%) | Â | Â | Â | Â | Â | Â |
  Not at all | 60.1 | 46.7 |  | 49.7 | 43.1 |  |
  Up to 20 cigarettes/day | 25.3 | 40.3 |  | 35.5 | 48.3 |  |
  More than 20 cigarettes/day | 14.7 | 13.0 | * | 14.8 | 8.6 |  |
Animals at home/yard (%) | 42.6 | 32.4 | * | 56.2 | 48.0 | * |
Farm animal at home/yard (%) | 0.6 | 4.7 | * | 0.5 | 4.2 | * |
Caesarian delivery (%)‡ | 31.7 | 39.0 | * | - - - | - - - |  |
Birth weight <2500gr (%)‡ | 13.9 | 18.0 | * | - - - | - - - |  |
Duration of breastfeeding (%)‡ |  |  |  |  |  |  |
  Not at all | 46.8 | 21.8 |  | - - - | - - - |  |
  <4 months | 32.5 | 24.2 |  | - - - | - - - |  |
  ≥4 months | 20.6 | 54.0 | * | - - - | - - - |  |
Bedroom sharing (%)‡ | 37.4 | 52.3 | * | - - - | - - - |  |
Nursery in first year of life (%)‡ | 9.3 | 4.7 | * | - - - | - - - |  |
Maternal smoking during pregnancy (%)‡ | 2.9 | 10.8 | * | - - - | - - - |  |
Active smoking (%)‡ | - - - | - - - |  | 1.7 | 1.3 |  |