Table 1

Demographic and clinical characteristics of the study sample

CharacteristicTotal valid observations (n = 776)Mean ± SD*
Child characteristics
 Male sex, %77652.4
 Nationality, %776
  Dutch70.8
  Other Western6.8
  Non-Western22.4
 Age, yr
  NEPSY-II-NL assessment7767.98 ± 0.98
  Brain imaging7767.97 ± 0.99
  CBCL assessment7766.03 ± 0.40
 CBCL attention-deficit/ hyperactivity problems score7763.77 ± 2.90
 Nonverbal IQ score710102.81 ± 14.34
 Gestational age at birth, wk77539.97 ± 1.77
 Birth weight, g7763470.41 ± 546.56
 Psychostimulant use, % yes7532.9
Maternal characteristics
 Education level, %764
  High57.2
  Medium31.0
  Low11.8
 Alcohol use during pregnancy, %722
  Never34.6
  Until pregnancy was known14.3
  Continued occasionally during pregnancy40.4
  Continued frequently during pregnancy†10.7
 Smoking during pregnancy, %749
  Never78.6
  Until pregnancy was known6.3
  Continued during pregnancy15.1
 Household income, %743
  > €200077.1
  €1200–200017.0
  < €12005.9

  • CBCL = Child Behavior Checklist; NEPSY = Developmental Neuropsychological Assessment; SD = standard deviation.

  • ↵* Unless otherwise indicated.

  • ↵† Frequent continued use was defined as ≥ 1 drink per week during at least 2 trimesters of pregnancy.