Table 3.
Matching criteria effectively minimized pairwise discordance in PAE and other prenatal and postnatal risk factors.
| Prenatal and Postnatal Risks | Monozygotic | Dizygotic | Full-siblings | Half-siblings | ||||
|---|---|---|---|---|---|---|---|---|
| N = 18 (9 pairs) | N = 78 (39 pairs) | N = 54 (27 pairs) | N = 18 (9 pairs) | |||||
| N Pairs | valid% | N Pairs | valid% | N Pairs | valid% | N Pairs | valid% | |
| Prenatal Alcohol Exposure (PAE): 4-Digit Code Rank | ||||||||
| Concordant Ranks between sibling pairs | ||||||||
| Overall | 9 | 100.0 | 39 | 100.0 | 27 | 100.0 | 9 | 100.0 |
| Rank 1: Confirmed absence of PAE | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 |
| Rank 2: PAE unknown | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 |
| Rank 3a: PAE confirmed, amount unknown | 4 | 44.5 | 15 | 38.5 | 13 | 48.1 | 3 | 33.3 |
| Rank 3b: PAE confirmed, amount low to moderate | 2 | 22.2 | 0 | 0.0 | 2 | 7.3 | 0 | 0.0 |
| Rank 4: PAE confirmed, amount high | 3 | 33.3 | 24 | 61.5 | 12 | 48.6 | 6 | 66.7 |
| Discordant Ranks between sibling pairs | ||||||||
| Overall | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 |
| Other Prenatal Risks: 4-Digit Code Rank | ||||||||
| Concordant Ranks between sibling pairs | ||||||||
| Overall | 9/9 | 100.0 | 39/39 | 100.0 | 27/27 | 100.0 | 8/9 | 88.9 |
| Valid Overall (excluding pairs with unknown risk) | 8/8 | 100.0 | 35/35 | 100.0 | 27/27 | 100.0 | 7/8 | 87.5 |
| Rank 1: no risk | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 |
| Rank 2: unknown risk | 1 | 11.1 | 4 | 10.3 | 0 | 0.0 | 1 | 11.1 |
| Rank 3: some risk | 8 | 88.9 | 35 | 89.7 | 27 | 100.0 | 7 | 77.8 |
| Rank 4: high risk | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 |
| Discordant Ranks between sibling pairs | ||||||||
| Overall | 0/9 | 0.0 | 0/39 | 0.0 | 0/27 | 0.0 | 1/9 | 11.1 |
| Valid Overall (excluding pairs with unknown risk) | 0/9 | 0.0 | 0/39 | 0.0 | 0/27 | 0.0 | 1/8 | 12.5 |
| Rank 4: high risk – Rank 3: some risk | 0 | 0.0 | 0 | 0.0 | 0 | 0.0 | 1 | 11.1 |
| Postnatal Risks: 4-Digit Code Rank | ||||||||
| Concordant Ranks between sibling pairs | ||||||||
| Overall | 9/9 | 100.0 | 34/39 | 87.2 | 21/27 | 77.8 | 6/9 | 66.7 |
| Valid Overall (excluding pairs with unknown risk) | 8/8 | 100.0 | 34/39 | 87.2 | 20/23 | 91.3 | 6/8 | 75.0 |
| Rank 1: no risk | 0 | 0.0 | 1 | 2.6 | 0 | 0.0 | 0 | 0.0 |
| Rank 2: unknown risk | 1 | 11.1 | 0 | 0.0 | 1 | 3.7 | 0 | 0.0 |
| Rank 3: some risk | 3 | 33.3 | 16 | 41.0 | 13 | 48.1 | 0 | 0.0 |
| Rank 4: high risk | 5 | 55.6 | 17 | 43.6 | 7 | 26.0 | 6 | 66.7 |
| Discordant Ranks between sibling pairs | ||||||||
| Overall | 0/9 | 0.0 | 5/39 | 12.8 | 6/27 | 22.2 | 3/9 | 33.3 |
| Valid Overall (excluding pairs with unknown risk) | 0/8 | 0.0 | 5/39 | 12.8 | 3/23 | 13.0 | 3/8 | 25.0 |
| Rank 3: some risk – Rank 2: unknown risk | 0 | 0.0 | 0 | 0.0 | 2 | 7.4 | 1 | 11.1 |
| Rank 3: some risk – Rank 1: no risk | 0 | 0.0 | 0 | 0.0 | 1 | 3.7 | 0 | 0.0 |
| Rank 3: some risk – Rank 4: high risk | 0 | 0.0 | 5 | 12.8 | 2 | 7.4 | 2 | 22.2 |
| Rank 4: high risk – Rank 2: unknown risk | 0 | 0.0 | 0 | 0.0 | 1 | 3.7 | 0 | 0.0 |
Abbreviations: PAE: prenatal alcohol exposure