Neurobehavioral and cognitive performances of children exposed to low-dose radiation in the Chernobyl accident: the Israeli Chernobyl Health Effects Study.

Exposure to low levels of ionizing radiation after the Chernobyl accident in the Ukraine could potentially have influenced the neurobehavioral and cognitive performances of exposed children. A cohort study of adolescents who were children at the time of the accident and who subsequently emigrated to Israel was conducted in 1998-2001. A total of 1,629 children (59% of all 2,769 invited) were included in the study (41% from higher contamination areas, 25% from lower contamination areas, 34% from noncontaminated areas). Mean scores of the Raven Standard Progressive Matrices Test were highest in children in all exposure groups whose parents had a high level of education. No overall relation was found between the cognitive function scores of the child and his/her putative radiation exposure level. Conners' test T scores did not differ significantly by level of exposure. Mothers of all exposure groups who were pregnant at the time of the accident gave their children significantly higher Conners' test scores than did those who were not pregnant. Scores for hyperactivity and attention-deficit/hyperactivity disorder were significantly higher among those who were in utero at the time of the accident. These results do not show differences of neurobehavioral or cognitive performance in exposed versus nonexposed children. There is a possible behavioral effect among offspring of pregnant mothers or mothers of very young children in all exposure levels.