Table 1. Study population characteristics.
Characteristic | All n = 620 | Urban n = 236 | Suburban n = 128 | Rural n = 256 |
---|---|---|---|---|
Sex, male | 312 (50.3) | 114 (48.3) | 71 (55.5) | 127 (49.6) |
Birth year | 1,986 ± 2.8 | 1,987 ± 2.7 | 1,987 ± 2.5 | 1,986 ± 2.9 |
Zygosity-chorionicity | ||||
Dizygotic-dichorionic | 356 (57.4) | 150 (63.6) | 74 (57.8) | 132 (51.6) |
Monozygotic-dichorionic | 106 (17.1) | 40 (16.9) | 14 (10.9) | 52 (20.3) |
Monozygotic-monochorionic | 158 (25.5) | 46 (19.5) | 40 (31.3) | 72 (28.1) |
Parental education | ||||
Low | 120 (38.7) | 41 (34.8) | 4 (6.3) | 59 (46.1) |
High | 190 (61.3) | 77 (65.2) | 44 (68.8) | 69 (53.9) |
Neighborhood income, euro | 18,831 ± 2,481 | 18,898 ± 2,426 | 19,755 ± 2,848 | 18,308 ± 2,196 |
Intelligence (WISC-R) | n = 620 | n = 236 | n = 128 | n = 256 |
Age at investigation | 11.0 ± 1.8 | 11.0 ± 1.7 | 10.9 ± 1.7 | 11.1 ± 1.9 |
Year of investigation | 1,998 ± 1.6 | 1,998 ± 1.4 | 1,998 ± 1.6 | 1,998 ± 1.7 |
Intelligence score (IQ) | ||||
Total | 105.3± 14.2 | 106.2 ± 13.2 | 104.8 ± 14.2 | 104.8 ± 15.1 |
Verbal | 106.2 ± 13.5 | 107.0 ± 12.9 | 106.1± 13.3 | 105.5 ± 14.2 |
Performance | 103.2 ± 15.2 | 103.9 ± 14.1 | 102.4 ± 15.7 | 103.0 ± 15.9 |
Behavior (CBCL) | n = 442 | n = 168 | n = 92 | n = 182 |
Age at investigation | 8.5 ± 2.2 | 8.4 ± 2.2 | 8.1 ± 2.0 | 8.7 ± 2.3 |
Year of investigation | 1,994 ± 0.5 | 1,994 ± 0.5 | 1,994 ± 0.5 | 1,994 ± 0.5 |
CBCL score | ||||
Total | 46.5 ± 9.9 | 47.0 ± 9.5 | 46.8 ± 9.7 | 45.9 ± 10.3 |
Externalizing | 46.3 ± 9.9 | 47.2 ± 9.6 | 46.2 ± 10.1 | 45.4 ± 10.1 |
Internalizing | 47.7 ± 9.4 | 48.0 ± 9.4 | 48.2 ± 9.4 | 47.0 ± 9.4 |
Data presented are means ± standard deviation or number (percentage).
CLBL, Child Behavior Checklist; WISC-R, Wechsler Intelligence Scale for Children-Revised.