Table 2.
Descriptive characteristics of the included and excluded sample
| Analysed | Excluded | Analysed vs. excluded χ 2 (df), P | |
|---|---|---|---|
| N | 1078 | 657 | |
| Ethnic group (language), N (%) | |||
| White British | 396 (36.7) | 264 (40.1) | 15.1 (3), 0.002 |
| Pakistani (English) | 329 (30.5) | 184 (28.0) | |
| Other (English) | 123 (11.4) | 105 (16.0) | |
| Any (not English) | 230 (21.3) | 104 (15.8) | |
| Migration history | |||
| Born in the UK | 664 (61.6) | 419 (63.8) | 1.1 (2), 0.57 |
| Migrated to UK before age 16 | 81 (7.5) | 43 (6.5) | |
| Migrated to UK on or after age 16 | 327 (30.3) | 190 (28.9) | |
| Missing | 6 (0.6) | 5 (0.8) | |
| Age at enrolment, mean (SD) | 27.6 (5.7) | 26.5 (5.6) | b t = 3.9, P < 0.001 |
| Relationship status at recruitment N (%) | |||
| Married and living together | 760 (70.5) | 415 (63.2) | 14.1 (2), 0.001 |
| Cohabiting | 181 (16.8) | 120 (18.3) | |
| Not living with a partner | 133 (12.3) | 121 (18.4) | |
| Missing | 4 (0.4) | 1 (0.2) | |
| IMD national rank quintile | |||
| Most deprived | 718 (66.6) | 456 (69.4) | 3.4 (4), 0.49 |
| 2 | 206 (19.1) | 109 (16.6) | |
| 3 | 112 (10.4) | 70 (10.7) | |
| 4 | 27 (2.5) | 11 (1.7) | |
| Least deprived | 15 (1.4) | 11 (1.7) | |
| Number of items lacked on the Family Resources Survey at recruitment | |||
| None | 461 (42.8) | 280 (42.6) | 1.3 (3), 0.74 |
| 1–2 | 298 (27.6) | 170 (25.9) | |
| 3–4 | 165 (15.3) | 98 (14.9) | |
| 5+ | 145 (13.5) | 99 (15.1) | |
| Missing | 9 (0.8) | 10 (1.5) | |
| ≥75th centile of self-reported distress measure, N (%)a,c | |||
| GHQ-28 during pregnancy | 302 (28.1) | 174 (26.8) | 0.35 (1), 0.56 |
| Missing | 4 (0.4) | 8 (1.2) | |
| GHQ-28 at 6 months | 257 (28.7) | 120 (30.8) | 0.57 (1), 0.45 |
| Missing | 182 (16.9) | 267 (40.6) | |
| Kessler-6 at 12 months | 258 (27.4) | 113 (32.5) | 3.2 (1), 0.07 |
| Missing | 136 (12.6) | 309 (47.0) | |
| GHQ-28 at 18 months | 251 (25.8) | 89 (30.4) | 2.3 (1), 0.13 |
| Missing | 107 (9.9) | 364 (55.4) | |
| Kessler-6 at 24 months | 248 (25.2) | 70 (31.3) | 3.4 (1), 0.06 |
| Missing | 94 (8.7) | 433 (65.9) | |
| Has CMD treatment Read codes/prescriptions, N (%) | |||
| N | 1078 | 322 | |
| Pre-birth | 79 (7.3) | 31 (9.7) | 1.8 (1), 0.18 |
| In first postnatal year | 118 (11.0) | 40 (12.5) | 0.54 (1), 0.46 |
| In second postnatal year | 139 (12.9) | 47 (14.6) | 0.62 (1), 0.43 |
| SDQ Perceived Difficulties question, N (%)a | |||
| N | 1078 | 335 | |
| Severe, serious or minor | 137 (12.7) | 20 (16.8) | 1.5 (1), 0.22 |
| Missing | 0 | 216 (64.5) | |
Excluded: did not have linked medical records, moved from Bradford, did not participate in any postnatal sweeps, missing SDQ
IMD index of multiple deprivation, GHQ General Health Questionnaire, SDQ Strengths and Difficulties Questionnaire
aPercentage of non-missing scores
b t test
cCentiles presented in this table were calculated using the whole BiB1000 sample (N = 1735)