| Race | |
| White | 1.0 (reference) |
| Black | 0.991 (95 to 1.02) |
| Hispanic | 1.333 (1.27 to 1.39) |
| Asian | 1.09 (1.00 to 1.20) |
| Birth weight, grams | |
| <500 | 4.207 (3.21 to 5.12) |
| 500–749 | 63.819 (47.95 to 84.93) |
| 750–999 | 77.255 (59.38 to 100.50) |
| 1000–1249 | 74.37 (57.23 to 96.65) |
| 1250–1499 | 43.847 (33.74 to 56.98) |
| 1500–1749 | 19.737 (15.18 to 25.67) |
| 1750–1999 | 8.222 (6.31 to 10.72) |
| 2000–2499 | 2.111 (1.60 to 2.80) |
| >2500 | 1.0 (reference) |
| Hypoxia | 0.776 (0.70 to 0.86) |
| Respiratory distress | 1.466 (1.42 to 1.51) |
| Perinatal infection | 0.851 (0.82 to 0.87) |
| Necrotising enterocolitis | 0.805 (0.75 to 0.85) |
| Intraventricular haemorrhage | 1.098 (1.05 to 1.14) |