HELIX subcohort characteristics
| Total | BiB | EDEN | INMA | KANC | MoBa | RHEA | |
| (n=1301) | (n=205) | (n=198) | (n=223) | (n=204) | (n=272) | (n=199) | |
| Age, years, median (IQR) | 8.1 (6.5; 8.9) | 6.6 (6.4; 6.8) | 11 (10; 11) | 8.8 (8.4; 9.2) | 6.4 (6.1; 6.8) | 8.4 (8.2; 8.8) | 6.5 (6.4; 6.6) |
| Sex, female (%) | 45.4 | 44.9 | 42.9 | 46.2 | 45.6 | 47.8 | 44.2 |
| Ethnicity, Caucasian (%) | 90 | 42.9* | 99.5 | 100 | 100 | 95.6 | 100 |
| Family affluence (%) | |||||||
| Low | 10.7 | 27.8 | 1 | 6.8 | 15.3 | 1.5 | 15.1 |
| Middle | 38.5 | 42.9 | 21.2 | 39.6 | 52.7 | 26.8 | 51.3 |
| High | 50.8 | 29.3 | 77.8 | 53.6 | 32 | 71.7 | 33.7 |
| Maternal smoking during pregnancy, yes (%) | 14.8 | 12.2 | 23.7 | 24.7 | 6 | 3.4 | 21.2 |
| Environmental tobacco smoke, yes (%) | 34.3 | 27.3 | 24.8 | 31.5 | 40.1 | 18.8 | 69.4 |
| Fruit intake, times/week, median (IQR) | 9 (6; 18) | 16 (10; 21) | 6.6 (3.3; 14) | 7.5 (3.6; 12) | 7.3 (3.8; 9.6) | 8.5 (6.2; 14) | 14 (8.6; 21) |
| Vegetable intake, times/week, median (IQR) | 6.5 (4; 10) | 6 (4; 10) | 8.2 (4.4; 11) | 6 (3; 8.5) | 6 (3.5; 8.5) | 6.5 (4; 10) | 8.5 (6; 14) |
| Visits to fast food restaurant, take away times/week, median (IQR) | 0.13 (0.13; 0.5) | 0.5 (0.13; 1) | 0.13 (0.13; 0.5) | 0.13 (0.13; 0.5) | 0.13 (0; 0.13) | 0.5 (0.13; 0.5) | 0.13 (0.13; 0.5) |
| Moderate to vigorous physical activity, min/day, median (IQR) | 36 (22; 55) | 42 (32; 62) | 17 (7.8; 29) | 26 (17; 44) | 42 (35; 57) | 35 (23; 63) | 49 (36; 61) |
| Food allergy, yes (%) | 20.7 | 21 | 16.7 | 35 | 16.2 | 18.8 | 15.6 |
| Asthma, yes (%) | 11.6 | 18.5 | 20.2 | 3.6 | 7.8 | 11.4 | 9.1 |
| Child zBMI (%) | |||||||
| Underweight/normal weight | 71.4 | 77.1 | 73.7 | 57.7 | 70 | 84.1 | 62.8 |
| Overweight | 18.8 | 15.1 | 21.2 | 23.6 | 20.2 | 6.2 | 20.6 |
| Obesity | 9.9 | 7.8 | 5.1 | 18.6 | 9.9 | 2.6 | 16.6 |
| Conners ADHD symptoms, yes (%) | 10.1 | 9.3 | 8.6 | 6.6 | 15.2 | 4.4 | 10.8 |
| CBCL, total problems, median (IQR) | 21 (10; 33) | 15 (8; 28) | 26 (16; 37) | 22 (12; 40) | 27 (17; 42) | 9 (5; 17) | 26 (16; 36) |
*44.9% of the subcohort BiB population is from South Asian ethnic origin and 12.1% of other ethnicity.
ADHD, Attention Deficit Hyperactivity Disorder; BiB, Born in Bradford; CBCL, child behaviour checklist; EDEN, Étude des Déterminants pré et postnatals du développement et de la santé de l’Enfant; HELIX, Human Early Life Exposome; INMA, INfancia y Medio Ambiente; KANC, Kaunus cohort; MoBa, Norwegian Mother and Child Cohort Study; zBMI, age standardized z-score for body mass index.