Table 1.
Participant information and cohort breakdown
| Total included | Monozygotic pairs | Dizygotic pairs | Unrelated test | Unrelated train | |
|---|---|---|---|---|---|
| Total | 1,115 | 170 | 219 | 526 | 200 |
| Site 20 | 387 | 75 | 86 | 184 | 60 |
| Site 21 | 371 | 34 | 81 | 166 | 90 |
| Site 22 | 357 | 75 | 68 | 176 | 50 |
| Age (mos, interview_age) | 121.6 | 122.5 | 122.0 | 121.6 | 120.7 |
| % female (gender) | 50 | 52 | 50 | 50 | 50 |
| % Ancestry: African (AFR) | 12.7 | 9.2 | 11.8 | 11.3 | 20.4 |
| % Ancestry: European (EUR) | 80.5 | 82.5 | 82.6 | 81.4 | 73.3 |
| % Ancestry: American (AMR) | 4.9 | 6.7 | 4.0 | 5.2 | 3.8 |
| % Ancestry: East Asian (EAS) | 2.0 | 1.6 | 1.6 | 2.1 | 2.5 |
| Ethnicity (race_ethnicity) | 1.667 | 1.658 | 1.63 | 1.73 | 1.58 |
Data were acquired from the publicly available ABCD data release 2.0.1. Participants were divided into cohorts to balance unrelated participants with the demographics of the twin participants, while respecting the demographic diversity of individual ABCD sites. Percent ancestry values reflect the percentage of a participant's genetic makeup attributed to a given ancestry, then averaged across participants. Ethnicity values represent a 4-level race/ethnicity model, where participants self-identified as White, Black, Hispanic, Asian, or other, and these coded values were averaged across participants.