Table 2.
Percentiles 75–90–95, mean and standard deviation for inattention, hyperactivity and ADHD symptoms.
| Inattention | Hyperactivity | ADHD | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Percentiles | Mean | sd | p * | Percentiles | Mean | sd | p * | Percentiles | Mean | sd | p * | ||||||||
| Variables | |||||||||||||||||||
| Child characteristics | |||||||||||||||||||
| Sex | Female | 0 | 1 | 2 | 0.33 | 1.13 | <0.001 | 0 | 1 | 3 | 0.43 | 1.23 | <0.001 | 0 | 2.1 | 5 | 0.76 | 1.97 | <0.001 |
| Male | 1 | 4 | 6 | 0.89 | 1.98 | 1 | 3 | 5 | 0.76 | 1.76 | 2 | 6 | 9 | 1.65 | 3.3 | ||||
| Preterm | No | 0 | 2 | 5 | 0.61 | 1.63 | 0.768 | 0 | 2 | 4 | 0.6 | 1.54 | 0.362 | 1 | 4 | 8 | 1.21 | 2.76 | 0.848 |
| Yes | 1 | 2 | 3 | 0.68 | 1.54 | 1 | 2 | 2 | 0.46 | 0.87 | 2 | 3 | 5 | 1.15 | 1.89 | ||||
| Sibling order | Not first | 0 | 2 | 4.15 | 0.63 | 1.61 | 0.884 | 0 | 2 | 4 | 0.59 | 1.48 | 0.871 | 1 | 4 | 7 | 1.21 | 2.66 | 0.997 |
| First | 0 | 2 | 5 | 0.61 | 1.67 | 0 | 2 | 4 | 0.6 | 1.57 | 1 | 5 | 8 | 1.21 | 2.84 | ||||
| Lives with mother/father | Both | 0 | 2 | 5 | 0.61 | 1.63 | 0.760 | 0 | 2 | 4 | 0.59 | 1.53 | 0.020 | 1 | 4 | 7.4 | 1.2 | 2.75 | 0.342 |
| Only one | 0 | 0 | 2.1 | 0.47 | 1.81 | 0 | 0.6 | 1.3 | 0.2 | 0.56 | 0 | 1.2 | 3.8 | 0.67 | 2.09 | ||||
| Number of people who they live with | ≤2 | 0 | 2 | 4 | 0.56 | 1.55 | 0.318 | 0 | 2 | 3.15 | 0.57 | 1.49 | 0.693 | 1 | 4 | 7.15 | 1.13 | 2.63 | 0.415 |
| > 2 | 0 | 2 | 5 | 0.67 | 1.73 | 0 | 2 | 4 | 0.61 | 1.55 | 1 | 4 | 7.55 | 1.27 | 2.87 | ||||
| Child´s age at the time of the test | ≤4.50 | 0 | 1 | 3 | 0.46 | 1.4 | 0.001 | 0 | 2 | 3 | 0.49 | 1.7 | 0.018 | 1 | 3 | 5 | 0.95 | 2.39 | 0.001 |
| > 4.50 | 0 | 3 | 5.65 | 0.79 | 1.87 | 0 | 3 | 4.65 | 0.72 | 1.37 | 1 | 5 | 9 | 1.51 | 3.11 | ||||
| Breastfeeding (weeks) | No | 1 | 4.7 | 6 | 1.02 | 2.17 | 0.010 | 0 | 3 | 5 | 0.78 | 1.83 | 0.028 | 2 | 8 | 10 | 1.8 | 3.54 | 0.007 |
| 0–16 | 0 | 2 | 5 | 0.67 | 1.67 | 1 | 3 | 5 | 0.79 | 1.91 | 1 | 5 | 8.35 | 1.47 | 3.13 | ||||
| 16–24 | 0 | 2.5 | 5 | 0.66 | 1.79 | 0 | 2 | 4 | 0.57 | 1.4 | 1 | 5 | 6.5 | 1.24 | 2.92 | ||||
| >24 | 0 | 2 | 3.7 | 0.49 | 1.39 | 0 | 2 | 3 | 0.48 | 1.28 | 1 | 4 | 6 | 0.97 | 2.24 | ||||
| Hg (μg/l) in umbilical cord | ≤8,2 | 0 | 2 | 5 | 0.64 | 1.690 | 0.608 | 0 | 2 | 3 | 0.58 | 1.58 | 0.791 | 1 | 4 | 7.75 | 1.22 | 2.87 | 0.653 |
| >8.2 | 0 | 2 | 4 | 0.59 | 1.590 | 0 | 2 | 4 | 0.55 | 1.46 | 1 | 4 | 7 | 1.14 | 2.68 | ||||
| Maternal characteristics | |||||||||||||||||||
| Cohort | Gipuzkoa | 0 | 1 | 3 | 0.42 | 1.29 | 0.012 | 0 | 1 | 2 | 0.35 | 1.18 | 0.004 | 0 | 3 | 5 | 0.77 | 2.22 | 0.002 |
| Sabadell | 0 | 2 | 5 | 0.62 | 1.62 | 1 | 2 | 4 | 0.69 | 1.6 | 1 | 4.8 | 7.9 | 1.31 | 2.8 | ||||
| Valencia | 0 | 3 | 6 | 0.8 | 1.92 | 0 | 3 | 4.1 | 0.7 | 1.69 | 1 | 5 | 9 | 1.5 | 3.1 | ||||
| Ferritin level (log scale) | ≤3.37 | 0 | 2 | 5 | 0.61 | 1.67 | 0.955 | 0 | 2 | 4 | 0.62 | 1.49 | 0.636 | 1 | 4 | 8 | 1.23 | 2.75 | 0.819 |
| >3.37 | 0 | 2 | 4.8 | 0.62 | 1.61 | 0 | 2 | 4 | 0.57 | 1.57 | 1 | 4.6 | 7 | 1.19 | 2.77 | ||||
| Maternal blood collection week | ≤12 | 0 | 2 | 5 | 0.67 | 1.72 | 0.300 | 0 | 2 | 4 | 0.61 | 1.53 | 0.824 | 1 | 5 | 8 | 1.27 | 2.82 | 0.462 |
| >12 | 0 | 2 | 4 | 0.56 | 1.55 | 0 | 2 | 4 | 0.59 | 1.53 | 1 | 4 | 7 | 1.15 | 2.7 | ||||
| Alcohol intake during pregnancy | ≤0.0201 | 0 | 3 | 5.8 | 0.71 | 1.850 | 0.019 | 0 | 2 | 4 | 0.67 | 1.65 | 0.052 | 1 | 5 | 9 | 1.39 | 3.12 | 0.013 |
| >0.0201 | 0 | 2 | 4 | 0.49 | 1.300 | 0 | 2 | 3 | 0.5 | 1.34 | 1 | 4 | 6 | 0.99 | 2.18 | ||||
| Pre-pregnancy BMI | Underweight | 0 | 2 | 2.9 | 0.51 | 1.1 | <0.001 | 0 | 1 | 2.9 | 0.49 | 1.39 | 0.073 | 0.5 | 4 | 4.9 | 1 | 2.01 | <0.001 |
| Normal weight | 0 | 2 | 4 | 0.49 | 1.44 | 0 | 2 | 4 | 0.54 | 1.42 | 1 | 4 | 6 | 1.03 | 2.46 | ||||
| Overweight | 0 | 3 | 6 | 0.78 | 1.92 | 1 | 2 | 3.4 | 0.69 | 1.68 | 1 | 5 | 9.4 | 1.47 | 3.31 | ||||
| Obese | 2 | 6 | 7.2 | 1.42 | 2.44 | 1 | 4 | 5.6 | 0.96 | 2.04 | 4 | 8.2 | 10.6 | 2.37 | 3.76 | ||||
| Age | ≤31 | 0 | 2 | 5 | 0.64 | 1.64 | 0.664 | 0 | 2 | 4 | 0.64 | 1.56 | 0.295 | 1 | 5 | 7 | 1.27 | 2.77 | 0.404 |
| >31 | 0 | 2 | 5 | 0.59 | 1.64 | 0 | 2 | 4 | 0.54 | 1.49 | 1 | 4 | 8 | 1.13 | 2.76 | ||||
| Mental health (14 months after birth) | ≤9 | 0 | 1 | 3 | 0.39 | 1.15 | 0.015 | 0 | 2 | 3 | 0.46 | 1.2 | 0.265 | 1 | 3 | 5 | 0.85 | 2 | 0.040 |
| >9 | 0 | 2 | 5 | 0.68 | 1.8 | 0 | 2 | 3 | 0.58 | 1.55 | 1 | 4 | 8 | 1.26 | 2.98 | ||||
| Parity | 0 | 0 | 2 | 5 | 0.61 | 1.67 | 0.921 | 0 | 2 | 4 | 0.6 | 1.57 | 0.833 | 1 | 5 | 8 | 1.22 | 2.84 | 0.954 |
| ≥1 | 0 | 2 | 4.05 | 0.62 | 1.6 | 0 | 2 | 4 | 0.59 | 1.48 | 1 | 4 | 7 | 1.21 | 2.65 | ||||
| Smoking in pregnancy | No | 0 | 2 | 4 | 0.54 | 1.54 | 0.003 | 0 | 2 | 3.45 | 0.53 | 1.45 | 0.006 | 1 | 4 | 6 | 1.08 | 2.6 | 0.001 |
| Yes | 1 | 4.4 | 6 | 1.06 | 2.11 | 1 | 4 | 5 | 0.97 | 1.93 | 2 | 7 | 10 | 2.03 | 3.51 | ||||
| Country of birth | Spain | 0 | 2 | 5 | 0.6 | 1.61 | 0.305 | 0 | 2 | 4 | 0.59 | 1.51 | 0.430 | 1 | 4 | 7.8 | 1.19 | 2.72 | 0.292 |
| Other | 1 | 2.3 | 6.3 | 0.87 | 2.08 | 1 | 2 | 5 | 0.76 | 1.81 | 2 | 5 | 7.3 | 1.63 | 3.38 | ||||
| Social class | Non-manual | 0 | 1 | 3 | 0.44 | 1.31 | <0.001 | 0 | 2 | 3 | 0.54 | 1.38 | 0.158 | 1 | 3 | 6 | 0.98 | 2.36 | 0.002 |
| Manual | 0 | 3 | 6 | 0.83 | 1.94 | 0 | 2 | 4 | 0.67 | 1.69 | 1 | 5 | 9 | 1.5 | 3.15 | ||||
| Education level | Primary | 0.25 | 5 | 7 | 1.03 | 2.25 | <0.001 | 0.25 | 2 | 4 | 0.7 | 1.68 | 0.283 | 2 | 6.3 | 10 | 1.73 | 3.41 | 0.001 |
| Secondary | 0 | 2 | 4 | 0.61 | 1.52 | 0 | 2 | 4 | 0.62 | 1.54 | 1 | 5 | 6 | 1.23 | 2.64 | ||||
| University | 0 | 1 | 3 | 0.39 | 1.28 | 0 | 2 | 3 | 0.51 | 1.41 | 0 | 3 | 5 | 0.9 | 2.41 | ||||
* t-test for mean comparison (2 samples) or ANOVA (more than two samples).