Table 1.
Characteristics of a nested case-control study of preschool ADHD in MoBa, 2004–2007.
| Preschool ADHD group | Controlsa | |
|---|---|---|
| Mean (SD) or N (%) | Mean (SD) or N (%) | |
|
| ||
| Total N | 260 | 549 |
| Maternal age at delivery (years) | 30.0 (4.05) | 30.9 (4.23) |
| Missing | 0 (0.0) | 2 (0.4) |
| Child sex, N | ||
| Male | 145 (55.8) | 275 (50.1) |
| Female | 115 (44.2) | 274 (49.9) |
| Missing | 0 (0.0) | 0 (0.0) |
| Maternal education, N (%) | ||
| Not a college graduate | 92 (35.4) | 121 (22.0) |
| College graduate | 108 (41.5) | 237 (43.2) |
| Post-college education | 56 (21.5) | 168 (30.6) |
| Missing | 4 (1.5) | 23 (4.2) |
| Marital status | ||
| Single/Co-inhabiting | 146 (56.2) | 257 (46.8) |
| Married | 113 (43.5) | 287 (52.3) |
| Missing | 1 (0.4) | 5 (0.9) |
| Parity | ||
| Nulliparous | 156 (60.0) | 270 (49.2) |
| Parous | 104 (40.0) | 277 (50.5) |
| Missing | 0 (0.0) | 2 (0.4) |
| Maternal ADHD symptoms | 33 (12.7) | 21 (3.8) |
| Missing | 2 (0.8) | 12 (2.2) |
| Maternal fish intake (g/day) | 26.2 (18.33) | 27.4 (19.05) |
| Missing | 4 (1.5) | 7 (1.3) |
| Any smoking in 1st or 2nd trimester | 62 (23.8) | 76 (13.8) |
| Missing | 1 (0.4) | 6 (1.1) |
| Any alcohol consumption in | 32 (12.3) | 65 (11.8) |
| 1st or 2nd trimester | ||
| Missing | 21 (8.1) | 44 (8.0) |
| Experienced financial difficulty in the past yearb | 67 (25.8) | 75 (13.7) |
| Missing | 1 (0.4) | 2 (0.4) |
| Birth year | ||
| 2004 | 26 (10.0) | 55 (10.0) |
| 2005 | 62 (23.9) | 131 (23.9) |
| 2006 | 90 (34.6) | 190 (34.6) |
| 2007 | 82 (31.5) | 173 (31.5) |
| Missing | 0 (0.0) | 0 (0.0) |
a
Controls are birth-year-stratified to account for changes in exposure or outcome frequency attributable to birth year.
b
Past year refers to the year before enrollment (around 17 weeks’ gestation).