Female sex of baby | 49 | 3.3, 1.2 to 8.6 | 2.3, 0.7 to 7.6 | 2.9, 1.1 to 7 | 3.6, 1.3 to 9.8 |
| | 0.01 | 0.1 | 0.01 | 0.01 |
Birth weight <5th centile‡ | 11 | 3.2, 1.1 to 9.4 | 1.9, 0.5 to 6.8 | 2.8, 1.1 to 7.3 | 3.2, 1.1 to 8.9 |
| | 0.03 | 0.2 | 0.02 | 0.02 |
Father completed school | 44 | 2.5, 0.9 to 7.2, | 2, 0.5 to 7.4 | 3.6, 1.4 to 9.4 | 3.8, 1.3 to 10.9 |
| | 0.07 | 0.2 | 0.009 | 0.01 |
Mother completed school | 25 | 3.2, 1.2 to 8.4 | 2.3, 0.7 to 7.3 | 2.7, 1.1 to 6.7 | 3.2, 1.1 to 8.7 |
| | 0.01 | 0.1 | 0.03 | 0.02 |
Exclusively breast fed | 77 | 3.2, 1.2 to 8.4 | 2.1, 0.7 to 7 | 2.7, 1.1 to 6.6 | 3.2, 1.1 to 8.7 |
| | 0.01 | 0.2 | 0.03 | 0.02 |
Baby ill in first 6 weeks | 27 | 3.2, 1.2 to 8.3 | 2.3, 0.7 to 7.5 | 2.9, 1.2 to 7.1 | 3.6, 1.3 to 9.7 |
| | 0.01 | 0.1 | 0.01 | 0.01 |
Prematurity | 3 | 3.1, 1.2 to 8.2 | 2.2, 0.7 to 7.1 | 2.9, 1.2 to 7.2 | 3.6, 1.3 to 9.9 |
| | 0.01 | 0.1 | 0.01 | 0.01 |