Demographic characteristics of the questionnaire-only sample and the subsample of children with completed questionnaires, stool samples for parasitological tests and skin-prick tests
| Questionnaire only# | Subsample | |
| Subjects n | 1982 | 1011 |
| Male sex | 993 (50.1) | 495 (49.0) |
| Birthweight ≥2500 g | 1736 (90.4) | 865 (88.6) |
| Born before term | 189 (9.9) | 93 (9.6) |
| Breastfeeding ≥6 months | 1705 (86.0) | 852 (84.7) |
| Current maternal smoking | 624 (31.5) | 322 (31.9) |
| Maternal schooling ≥8 yrs | 481 (24.3) | 195 (19.3)+ |
| ≥1 sibling | 1373 (69.3) | 730 (72.2) |
| Humid household | 893 (45.1) | 474 (46.9) |
| Poor neighbourhood | 1777 (99.7) | 956 (94.7)+ |
| Maternal asthma | 149 (7.5) | 78 (7.7) |
| Paternal asthma | 108 (5.5) | 58 (5.8) |
| Wheeze in past 12 months | 510 (25.6) | 273 (27.0) |
| Active asthma | 184 (9.3) | 93 (9.2) |
| Atopy | NA | 131 (13.0) |
| Bronchiolitis aged <2 yrs | 136 (6.9) | 63 (6.3) |
| Severe asthma¶ | 130 (6.6) | 70 (6.9) |
Data are presented as n or n (%). Denominators for the variables may differ slightly due to missing values. NA: not available. #: International Study of Asthma and Allergies in Childhood Phase II questionnaire; ¶: ≥4 attacks; +: p≤0.01.