Characteristics of the study sample stratified by sex
| Boys (n=5460) N (%)*/mean (SD) | Girls (n=5480) N (%)*/mean (SD) | p Value for sex difference | |
|---|---|---|---|
| Parental absence (0–7 years) | |||
| No | 4145 (71.4) | 4160 (72.5) | 0.33 |
| Yes | 1315 (28.6) | 1320 (27.5) | |
| Age at parental absence† | |||
| Birth to 9 months | 92 (6.3) | 91 (5.9) | 0.30 |
| 9 months–3 years | 620 (50.7) | 606 (48.4) | |
| 3–5 years | 360 (26.0) | 378 (29.7) | |
| 5–7 years | 243 (17.1) | 245 (16.0) | |
| Which parent absent† | |||
| Father | 1254 (95.2) | 1245 (93.2) | 0.32 |
| Mother | 35 (2.6) | 38 (3.9) | |
| Mother and father | 26 (2.2) | 37 (3.0) | |
| Reason for absence† | |||
| Death | 30 (1.8) | 25 (1.4) | 0.41 |
| Other reason | 1285 (98.2) | 1295 (98.6) | |
| Ever smoked (11 years) | |||
| No | 5295 (96.4) | 5390 (98.1) | <0.001 |
| Yes | 165 (3.6) | 90 (1.9) | |
| Ever drank (11 years) | |||
| No | 4719 (85.3) | 7998 (89.4) | <0.001 |
| Yes | 741 (14.7) | 482 (10.6) | |
| Ever got drunk (11 years)‡ | |||
| No | 662 (88.1) | 452 (93.4) | <0.001 |
| Yes | 79 (11.9) | 30 (6.6) | |
| Mother smoked during pregnancy | |||
| No | 4057 (71.6) | 4131 (72.0) | 0.74 |
| Yes | 1403 (28.4) | 1349 (28.0) | |
| Maternal age at birth (0 years) | 28.5 (5.8) | 28.6 (5.8) | 0.42 |
| Highest parental education (9 months) | |||
| None | 357 (7.6) | 389 (8.0) | 0.99 |
| Overseas qualification | 98 (1.7) | 99 (1.7) | |
| NVQ1 | 257 (5.5) | 277 (5.8) | |
| NVQ2 | 1300 (26.1) | 1297 (25.9) | |
| NVQ3 | 928 (16.8) | 911 (16.5) | |
| NVQ4 | 2100 (35.7) | 2065 (35.2) | |
| NVQ5 | 420 (6.7) | 442 (6.9) | |
| Gestational age,§ weeks (0 years) | 40.0 (38.6, 40.9) | 40.0 (39.0, 40.9) | 0.11 |
| Birth weight, kg (0 years) | 3.4 (0.6) | 3.3 (0.6) | <0.001 |
| Mother's ethnicity (0 years) | |||
| White | 4708 (87.7) | 4665 (87.3) | 0.16 |
| Indian | 155 (2.5) | 139 (2.0) | |
| Pakistani/Bangladeshi | 331 (4.5) | 393 (5.5) | |
| Black | 134 (2.7) | 141 (2.6) | |
| Other/mixed | 132 (0.3) | 142 (2.6) | |
| Child's age at age 11 survey, years | 11.2 (0.34) | 11.2 (0.33) | 0.27 |
*Weighted percentages shown.
†Of those who had experienced parental absence (n=2635).
‡Of those who had ever drunk (n=1223).
§Median and IQR reported as gestational age was negatively-skewed. NVQ, National Vocational Qualification.