Inborn |
No | 46/673 | 6.8 | Ref | | |
Yes | 116/1579 | 7.4 | 1.1 | 0.8 to 1.5 | 0.7 |
Gender |
Female | 65/1027 | 6.3 | Ref | | |
Male | 98/1229 | 8.0 | 1.3 | 0.9 to 1.8 | 0.1 |
Pregnancy |
Multiple | 47/720 | 6.5 | Ref | | |
Singleton | 116/1536 | 7.6 | 1.2 | 0.8 to 1.7 | 0.4 |
Gestational age |
31–32 weeks | 79/1220 | 6.5 | Ref | | |
Less than 31 weeks | 84/1036 | 8.1 | 1.3 | 0.9 to 1.8 | 0.1 |
Birth weight |
More than 1500 g | 63/967 | 6.5 | Ref | | |
1000–1500 g | 73/1003 | 7.3 | 1.1 | 0.8 to 1.5 | |
Less than 1000 g | 27/286 | 9.4 | 1.6 | 1.0 to 2.5 | 0.1 |
Intrauterine growth restriction |
No | 146/2083 | 7.0 | Ref | | |
Yes | 17/169 | 10.1 | 1.5 | 0.9 to 2.5 | 0.1 |
BPD at 28 days |
No | 145/1992 | 7.3 | Ref | | |
Yes | 18/264 | 6.8 | 0.9 | 0.6 to 1.5 | 0.8 |
Siblings at home |
No | 62/1054 | 5.9 | Ref | | |
Yes | 100/1090 | 8.4 | 1.5 | 1.1 to 2.0 | 0.02 |
Maternal smoking |
No | 125/1802 | 6.9 | Ref | | |
Yes | 38/454 | 8.4 | 1.2 | 0.8 to 1.8 | 0.3 |
Paternal smoking |
No | 129/1737 | 7.4 | Ref | | |
Yes | 34/519 | 6.6 | 0.9 | 0.6 to 1.3 | 0.5 |
Monoparental (mother) family |
No | 139/2028 | 6.9 | Ref | | |
Yes | 17/129 | 13.2 | 2.1 | 1.2 to 3.5 | <0.01 |
Date of discharge |
After December 2000 | 15/427 | 3.5 | Ref | | |
Before October 2000 | 75/1080 | 6.9 | 2.0 | 1.2 to 3.6 | |
October–December 2000 | 73/749 | 9.7 | 3.0 | 1.7 to 5.2 | <0.001 |
Age at onset of exposure |
More than 3 months | 33/607 | 5.4 | Ref | | |
3 months or less | 130/1649 | 7.9 | 1.5 | 1.0 to 2.2 | <0.05 |