Table 1 Distribution of the main epidemiological variables in ALSPAC
From: DNA methylation mediates the association between breastfeeding and early-life growth trajectories
| Â | Boys | Girls | Â | Boys | Girls |
|---|---|---|---|---|---|
N = 358 | N = 374 | With DNA methylation available | |||
EXBF (in months) | Â | Â | Age (years) | Â | Â |
0 | 117 (32.7%) | 116 (31.0%) | 0 | 331 | 337 |
1 | 19 (5.3%) | 24 (6.4%) | 1 | 0 | 0 |
2 | 62 (17.3%) | 45 (12.0%) | 2 | 0 | 0 |
3 | 108 (30.2%) | 125 (33.4%) | 3 | 0 | 0 |
4 | 50 (14.0%) | 47 (12.6%) | 4 | 0 | 0 |
≥ 5 | 2 (0.6%) | 17 (4.5%) | 5 | 0 | 0 |
Family weekly disposable income | Â | Â | 6 | 0 | 2 |
< £100 | 8 (2.2%) | 6 (1.6%) | 7 | 452 | 456 |
£1–199 | 43 (12.0%) | 36 (9.6%) | 8 | 0 | 0 |
£200–299 | 89 (24.9%) | 103 (27.5%) | 9 | 0 | 0 |
£300–399 | 88 (24.6%) | 87 (23.3%) | 10 | 0 | 0 |
> £400 | 116 (32.4%) | 118 (31.1%) | 11 | 0 | 0 |
Missing | 14 (3.9%) | 24 (6.4%) | Â | Â | Â |
Mother's education | Â | Â | 12 | 0 | 0 |
CSE/none | 24 (6.7%) | 27 (7.2%) | 13 | 0 | 0 |
Vocational | 28 (7.8%) | 17 (4.5%) | 14 | 3 | 1 |
O level | 109 (30.4%) | 126 (33.7%) | 15 | 156 | 178 |
A level | 112 (31.3%) | 115 (30.7%) | 16 | 196 | 186 |
University degree | 85 (23.7%) | 89 (23.8%) | 17–18 | 83 | 104 |
Mother's ever smoking status | Â | Â | Â | Â | Â |
No | 319 (89.1%) | 331 (88.5%) | Â | Â | Â |
Yes | 39 (10.9%) | 43 (11.5%) | Â | Â | Â |
Birth weight (in kg) | Â | Â | Â | Â | Â |
Mean (± SD) | 3.5 (± 0.5) | 3.4 (± 0.4) |  |  |  |
Mother's pre-pregnancy BMI | Â | Â | Â | Â | Â |
Mean (± SD) | 22.9 (± 4.0) | 22.8 (± 3.6) |  |  |  |
Gestational age at birth (in weeks) | Â | Â | Â | Â | Â |
Mean (± SD) | 39.6 (± 1.5) | 39.7 (± 1.4) |  |  |  |