Global Environmental & Occupational Health
BELARUS:
In-Utero Exposure to Chornobyl Radiation
Through
our ITREOH program, we are continuing a cohort morbidity
study of children with in utero exposure to Chornobyl
radiation in Belarus and Russia. The Principal Investigator
of this study is Dr. Irina Dardynskaia, who began this
work in 1988 in Belarus. This study follows 1620 children
exposed in utero and born between April 26, 1986, and
December 31, 1987. During pregnancy, mothers of these
children lived in Belarus territories with varying degrees
of radionuclide contamination. The main goal of this
study is to assess the clinical and functional health
consequences of in utero radiation exposure in different
dose ranges, with particular attention to trends in sexual
and psychological growth and development, immune related
disorders and their relationship to estimated doses received
from radioiodine and radiocesium.
Our ITREOH program
supported the collaborative efforts between U.S. and
Belarussian scientists in:
- establishment of a computer database the 1620 participants;
- updating health examination data through 2,000;
- confirmation of data accuracy through validation
of a sample; and
- in utero dose reconstruction for a sample of
185 full-term children.
The
methodology for in utero dose reconstruction was developed
through collaborative efforts between scientists of three
countries ( Belarus, Russia and US). The results on utero
dose reconstruction are presented in a draft of our paper
submitted to Radiation Research13. Three Visiting Scientists
were trained in principles of radiation risk assessment,
and three scientists participated in in-country training
on in utero dose reconstruction.
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Chornobyl Nuclear
Power Plant
The
Belarussian physicians assigned
to special "Chornobyl" teams
continue to collect data from
annual mandatory examinations
of these children using the same surveillance
protocol. The hard copy files
of the annual examination results
of these children from 1988 to
1991 and data obtained in part
on follow-up examination from
1992-1997 are currently being
analyzed at UIC. These children are now 15
years of age. An additional and
more intensive clinical and endocrinologic examination during
this pubertal period will yield valuable information on effects
of in utero irradiation at low to medium doses on the growth,
development, and health of the exposed children. |
The study participants included 1260 children who were identified
who were born between April 26, 1986, and December 31, 1987 (Study
Groups 1 and 2) from lists of children undergoing mandatory surveillance
in the Minsk Chernobyl Dispensary. During pregnancy mothers of these
children lived in highly contaminated territories in several raions
of three Belarussian Oblasts, Gomel, Mogilev, and Brest. The locations
of these regions are shown in Figure 1. The mothers of 670 children
(Study Group 1) were exposed both to radiocesiums and radioiodines.
The mothers of 590 children (Study Group 2) were exposed mainly to radiocesiums.
The Control Group (Study Group 3) consists of 360 children born between April
26, 1986, and December 31, 1987, to mothers living throughout pregnancy in
the uncontaminated Braslav Raion of Vitebsk Oblast. These control children
were randomly selected from medical records of family-practice clinics and
were matched to Study Groups 1 and 2 by age and sex. Groups 1, 2, and 3 underwent
similar protocol-based examinations which included child's growth and development
data, neurological and ophthalmologic exams; thyroid-function tests; clinical,
and in some cases, ultrasound examination of the thyroid; and complete blood
counts. In utero dose reconstruction has been completed on a sample of 185
children from this cohort. Data, obtained from the dose reconstruction show
that more than one fourth of them received doses higher than 100 mGy from
131I.
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