Table 1.
Demographic Characteristics of the Sample
| Variable | Whole ALSPAC Sample (N = 13,801) | Subsample (n = 5,084) |
|---|---|---|
| Maternal age (y) at birth, mean, SD | 28.0, 4.97 | 29.14, 4.60 |
| Mother's highest educational qualification, n (%) | ||
| CSE | 2,522 (20.2) | 671 (13.2) |
| Vocational | 1,228 (9.8) | 441 (8.7) |
| 0 level | 4,323 (34.6) | 1,800 (35.5) |
| A level | 2,803 (22.5) | 1,324 (26.1) |
| Degree | 1,607 (11.0) | 833 (16.4) |
| Living situation (during pregnancy), n (%) | ||
| Living with partner | 12,426 (84.7) | 4,766 (94.8) |
| Living without partner | 1,160 (8.5) | 262 (5.2) |
| Smoking during pregnancy, n (%) | 2,436 (20) | 741 (16.9) |
| Alcohol during pregnancy, n (%) | 2,200 (31.8) | 1,052 (20.7) |
| Maternal anxiety during pregnancy (18 weeks), mean, SD | 4.93, 3.55 | 4.63, 3.36 |
| Maternal depression during pregnancy (18 weeks), mean, SD | 6.98, 4.86 | 6.45, 4.56 |
| Maternal anxiety during pregnancy (32 weeks), mean, SD | 5.14, 3.60 | 4.87, 3.45 |
| Maternal depression during pregnancy (32 weeks), mean, SD | 7.08, 5.08 | 6.71, 4.86 |
| Maternal postnatal anxiety (8 weeks), mean, SD | 3.42, 3.34 | 3.32, 3.22 |
| Maternal postnatal depression (8 weeks), mean, SD | 6.06, 4.80 | 5.85, 4.59 |
| Gender, n (%) | ||
| Male | 7,318 (51.7) | 2,685 (52.8) |
| Female | 6,825 (48.3) | 2,399 (47.2) |
| Child 5HTTLRP genotype, n (%) | ||
| Low expression | — | 1,187 (23.3) |
| Medium expression | — | 2,595 (51.1) |
| High expression | — | 1,302 (25.6) |
| Child reactivity score at 6 months, mean, SD | ||
| Males | −0.15, 2.69 | −0.26, 2.69 |
| Females | 0.16, 2.76 | 0.07, 2.77 |
Note: ALSPAC = Avon Longitudinal Study of Parents and Children; CSE = Committee on Special Education.