Table 1.
Distribution of socioeconomic, maternal and familial indicators in the original ALSPAC cohort of girls and in various sub-samples used in the study
| Risk factor | Total sample of females in ALSPAC (n = 7056) |
Sample with complete data on age at menarche onset (n = 4148) |
Sample with complete responses on SMFQ at 14 years (n = 3073) |
Full sample: complete data on age at menarche + complete SMFQ responses at 14 years + data on father presence/absence 0–10 years (n = 2675) |
Complete sample: complete data on age at menarche + complete SMFQ responses at 14 years + data on father presence/absence 0–10 years + data on antenatal confounders (n = 2057) |
|---|---|---|---|---|---|
| (%) | (%) | (%) | (%) | (%) | |
| Social group | |||||
| Non-manual | 50.8 | 55.7 | 57.4 | 58.6 | 58.6 |
| Manual | 49.2 | 44.3 | 42.6 | 41.4 | 41.4 |
| Sample n | 5618 | 3600 | 2714 | 2455 | 2057 |
| Homeownership status | |||||
| Owned | 73.4 | 81.3 | 83.4 | 84.2 | 85.8 |
| Privately rented | 26.6 | 18.7 | 16.6 | 15.8 | 14.2 |
| Sample n | 6344 | 3793 | 2818 | 2527 | 2057 |
| Car access | |||||
| Yes | 89.3 | 93.8 | 94.9 | 95.3 | 95.8 |
| No | 10.7 | 6.2 | 5.1 | 4.7 | 4.2 |
| Sample n | 6344 | 3786 | 2812 | 2521 | 2057 |
| Major financial problems | |||||
| No | 86.3 | 88.9 | 89.1 | 89.2 | 89.1 |
| Yes | 13.7 | 11.1 | 10.9 | 10.8 | 10.9 |
| Sample n | 5790 | 5183 | 2627 | 2365 | 2057 |
| Mother’s educational qualifications | |||||
| ≥High school | 70.4 | 76.8 | 79.9 | 81.6 | 83.0 |
| No qualifications | 29.6 | 23.2 | 20.1 | 18.4 | 17.0 |
| Sample n | 6031 | 3775 | 2817 | 2541 | 2057 |
| Family size | |||||
| <3 | 94.1 | 95.6 | 95.8 | 96.0 | 96.2 |
| 3+ | 5.9 | 4.4 | 4.2 | 4.0 | 3.8 |
| Sample n | 6306 | 3782 | 2809 | 2517 | 2057 |
| Early parenthood | |||||
| No | 95.2 | 97.7 | 98.3 | 98.5 | 99.0 |
| Yes | 4.8 | 2.3 | 1.7 | 1.5 | 1.0 |
| Sample n | 6756 | 3936 | 2906 | 2586 | 2057 |
ALSPAC Avon Longitudinal Study of Parents and Children; SMFQ Short Mood and Feelings Questionnaire