Antenatal Exposure of Persons from Belarus Following the Chernobyl Accident: Neuropsychiatric Aspects

Ten years follow-up investigation of intellectual development of 250 persons from Belarus exposed in utero following the Chernobyl accident has been conducted. Exposed cohort was compared with a control group of 250 persons in the same age from nonand slightly contaminated regions. For each study subject, individual antenatal doses were reconstructed for the following pathways of exposure: (1) internal doses to thyroid gland arising from the intake of I via inhalation or ingestion; and (2) external doses from radionuclides deposited on the ground. Neuropsychiatry and psychological examinations were performed among persons of both groups at the age 6−7 years, 10−12 years, and 15−16 years. At the age of 6−7 years the persons in the exposed group had a mean full-scale intelligent quotient (IQ) lower than the control group. At the age of 10−12 and 15−16 years there were no statistically significant differences between the two groups. Positive dynamics of intellectual development in persons of both groups has been observed up to age of 15−16 years. No statistically significant correlation was found in exposed group between individual thyroid dose as well as individual antenatal external dose and IQ at the different ages. In both groups we notice a positive moderate correlation between IQ of persons and the educational level of their parents. We conclude that probably a significant role in the genesis of borderline intellectual functioning and emotional disorders in the exposed group of persons was played by unfavorable factors such as a low educational level of parents, the break of micro social contacts and adaptation difficulties, which appear following the evacuation and relocation from the contaminated areas.