Table 2.
Behavioral characteristics of study population in nested case–cohort study of preschool attention-deficit hyperactivity disorder in the Norwegian Mother, Father and Child Cohort (MoBa), birth years 2004–2008.
| Preschool ADHD Cases (n = 259) | Sub-Cohort (n = 547) | |||
|---|---|---|---|---|
| n | % | n | % | |
| (Mean, SD) | (Mean, SD) | |||
| Any maternal smoking during pregnancy up until the ~17th week of gestation | ||||
| Yes | 61 | 23.6 | 75 | 13.9 |
| No | 197 | 76.4 | 466 | 86.1 |
| Missing (n) | 1 | 6 | ||
| Any maternal alcohol use during pregnancy up until the ~17th week of gestation | ||||
| Yes | 32 | 13.4 | 65 | 12.9 |
| No | 207 | 86.6 | 438 | 87.1 |
| Missing (n) | 20 | 44 | ||
| Fresh fruit consumption during pregnancy up until ~22 weeks gestation (servings per day) | (2.0, 1.4) | (2.1, 1.3) | ||
| Missing (n) | 4 | 7 | ||
| Raw vegetable consumption during pregnancy up until ~22 weeks gestation (servings per day) | (1.4, 0.8) | (1.4, 0.9) | ||
| Missing (n) | 8 | 21 | ||
| Self-reported pesticide exposure * | ||||
| Yes | 15 | 6.1 | 25 | 4.8 |
| No | 230 | 93.9 | 495 | 95.2 |
| Missing(n) | 14 | 27 | ||
| Season of prenatal urine collection | ||||
| Winter | 70 | 27.3 | 156 | 28.5 |
| Fall | 56 | 21.6 | 119 | 21.8 |
| Spring | 66 | 25.5 | 135 | 24.7 |
| Summer | 67 | 25.9 | 137 | 25.1 |
| Missing (n) | 0 | 0 | ||
Note: ADHD, attention-deficit hyperactivity disorder; SD, standard deviation, * Maternal self-report of contact with weed killers, insecticides, or fungicides either at work or in leisure time during the six months prior to 17th week of gestation.