Demographic data of study infants
| Sex (M:F) | 34:35 |
| Mean (range) age at test (days) | 37.3 (24–55) |
| Mean (range) length at test (cm) | 56.2 (52–61) |
| Mean (range) weight at test (kg) | 4.6 (3.1–5.8) |
| Maternal smokers | 8 (11.6%) |
| Paternal smokers | 14 (20.3%) |
| Maternal asthma | 32 (46.4%) |
| Paternal asthma | 15 (21.7%) |
| Both parents asthmatic | 4 (5.8%) |