Table 3.
Sample characteristics and the prevalence of asthma by early life events and parental health.
| Characteristics | No. (%) of children | Prevalence of asthma (%) | P* |
|---|---|---|---|
| Threatening preterm labor: | 0.041 | ||
| no | 1333 (91.1) | 6.9 | |
| yes | 131 (8.9) | 12.2 | |
| Preterm birth | 1.000 | ||
| no | 1411 (96.4) | 7.4 | |
| yes | 53 (3.6) | 7.5 | |
| Cesarean section: | 1.000 | ||
| no | 1383 (94.5) | 7.4 | |
| yes | 81 (5.5) | 7.4 | |
| Parity: | 0.670 | ||
| 1 | 1114 (76.1) | 7.5 | |
| ≥2 | 350 (23.9) | 6.9 | |
| Birth weight (g): | 0.027 | ||
| ≤2500 | 51 (3.5) | 3.9 | |
| 2501-3000 | 212 (14.5) | 7.1 | |
| 3001-3500 | 740 (50.5) | 6.4 | |
| 3501-4000 | 308 (21.0) | 9.1 | |
| >4000 | 89 (6.1) | 12.4 | |
| unknown | 64 (4.4) | 7.8 | |
| History of breastfeeding: | <0.001 | ||
| never breastfed | 151 (10.3) | 14.6 | |
| ever breastfed | 1313 (89.7) | 6.5 | |
| Allergies in infancy: | <0.001 | ||
| no | 765 (52.3) | 5.0 | |
| yes | 699 (47.7) | 10.0 | |
| Bronchitis and/or pneumonia in infancy: | <0.001 | ||
| no | 1099 (74.4) | 1.9 | |
| yes | 365 (25.6) | 23.1 | |
| Self-reported parental allergies: | <0.001 | ||
| none | 1149 (78.5) | 4.2 | |
| one parent | 272 (18.6) | 17.3 | |
| both parents | 43 (2.9) | 30.2 | |
| Asthma in at least one parent: | 0.571 | ||
| no | 1453 (99.2) | 7.4 | |
| yes | 11 (0.8) | 9.1 |
*Pearson χ2 test or Fisher exact test.