| Outcome | Combined, adjusted OR (95% CI) | p Value from test for between-country heterogeneity |
| Wheeze | 1.43 (1.36 to 1.49) | 0.16 |
| Asthma | 1.35 (1.20 to 1.51) | <0.01 |
| Bronchitis | 1.38 (1.29 to 1.47) | 0.01 |
| Nocturnal dry cough | 1.30 (1.22 to 1.39) | 0.41 |
| Morning cough | 1.50 (1.31 to 1.73) | <0.01 |
| Sensitivity to inhaled allergens | 1.33 (1.23 to 1.44) | 0.17 |
| Hay fever | 1.35 (1.18 to 1.53) | 0.20 |
| Woken by wheeze | 1.49 (1.28 to 1.74) | <0.01 |
ORs are adjusted for area and individual risk factors: age, sex, parental education, nationality, household crowding, gas for cooking, unvented heater, post- and prenatal exposure to tobacco smoke, birth order, and “ever had a pet”.