Increasing risk of SIDS with parity in the US 1995–1999, hypothesised to represent an infection vector from siblings during the school session25
| Live birth order of a SIDS* | Black infants—SIDS/1000 | White infants—SIDS/1000 |
|---|---|---|
| *Siblings may not all be alive or living at home. | ||
| 1 | 0.91 | 0.51 |
| 2 | 1.52 | 0.69 |
| 3 | 1.78 | 0.75 |
| 4 | 2.45 | 0.88 |
| 5 | 2.80 | 1.05 |
| 6 or more | 3.17 | 0.94 |