Table 1.
Characteristics of women with full reproductive histories compared to those with incomplete reproductive histories as determined from five questionnaires
| Women with incomplete data n=10262 | Women with complete data n=3451 | p Value | |
|---|---|---|---|
| Categorical variables—n (%) | |||
| Ethnicity | n=8653 | n=3417 | |
| White | 8381 (96.9) | 3370 (98.6) | <0.001 |
| Social class | n=7927 | n=3335 | |
| I | 842 (10.6) | 664 (19.9) | <0.001 |
| II | 3099 (39.1) | 1601 (48.0) | |
| III (non-manual) | 2135 (26.9) | 738 (22.1) | |
| III (manual) | 1261 (15.9) | 258 (7.7) | |
| IV and V | 590 (7.4) | 74 (2.2) | |
| Education | n=8739 | n=3425 | |
| University level or above | 826 (9.5) | 742 (21.7) | <0.001 |
| Single parent household | n=9136 | n=3403 | |
| Yes | 616 (6.7) | 102 (3.0) | <0.001 |
| Ever smoked | n=9365 | n=3441 | |
| Yes | 5124 (54.7) | 1369 (39.8) | <0.001 |
| Continuous variables—mean (SD*) | |||
| Age at birth of the ALSPAC index child | n=10258 | n=3451 | <0.001 |
| 27.4 (5.0) | 29.8 (4.4) | ||
*T test for normally distributed data.
ALSPAC, Avon Longitudinal Study of Parents and Children.