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1 ANTENATAL EXPOSURE FOLLOWING THE CHERNOBYL ACCIDENT: NEUROPSYCHIATRIC ASPECTS ﾁ ﾁ : ﾁ S.A. Igumnov 1, V.V. Drozdovitch 2 1 Belarusian State Pedagogical University,Department of Psychology,Minsk,Belarus 2 Joint Institute of Power and Nuclear Research - "Sosny",Branch "Institute of Power Engineering Problems", Minsk, Republic of Belarus ｨｮｨｬｨｪ0609 1, ｨｨ ﾂ ｨｮ0909ｨｺｨｨｨｦ ｨｮ01ｨ 0809ｨｰ0902ｨｪｨｪ04ｨｦ ｨ ｨｨ ﾂ0209ｨｺｨｨｨｦ ｨｮｨｪｨｨ ｨｨｨｰ02ｨｰ,ｨｺｨ ｨ 0709ｨｨ ｨｨｨｨ,00ｨｨｨｪ09ｨｺ,090205ｨ 08ｨｮ09ｨｹ 2 02ｨ ｨｲ0201ｨｨｨｪ02ｨｪｨｪ04ｨｦ ｨｨｨｪ09ｨｰｨｨｨｰｨｮｨｰ 05ｨｪ ｨｰｨｨ ﾂ0209ｨｺｨｨ01 ｨｨ ｨｪ0401 ｨｨ ｨ ｨｪｨｨｨｦ - "050609ｨｪ04", 06ｨｰ ｨｪｨｨ02 "06ｨｪ09ｨｰｨｨｨｰｨｮｨｰ ｨ 0502ｨｬ 05ｨｪ ｨｰｨｨｨｺｨｨ", 00ｨｨｨｪ09ｨｺ, ｨｮｨ 05ｨｨｨｺｨ ｨ 08ｨｮ09ｨｹ Abstract Ten years follow-up investigation of intellectual development of 250 persons from Belarus exposed in utero following the Chernobyl accident and a control group of 250 persons from non- and slightly contaminated regions has been conducted. Neuropsychiatry and psychological examinations were performed among persons of both groups at the age of 6-7, 10-12, and years. Mean antenatal internal dose to thyroid arising from the intake of 131I among persons of exposed group is 390 ﾀ550 mgy (maximal dose mgy), in control group - 35 ﾀ65 mgy. Mean antenatal external dose among persons of exposed group is 10 ﾀ13 mgy,maximal dose - 91 mgy. At the age of 6-7 years the persons in the exposed group had a mean Full Scale IQ lower than the control group (89.6 ﾀ10.2 vs 92.1 ﾀ10.5,p=0.007). At the age of years there was no statistically significant difference between the two groups (94.3 ﾀ10.4 vs 95.8 ﾀ10.9,p=0.117). Positive dynamics of intellectual development in persons of both groups has been observed up to age of years (98.7 ﾀ10.2 ｨｨ 99.5 ﾀ10.5,p=0.171). 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 social-psychological and social-cultural factors. Keywords: Chernobyl accident, exposure in utero, intellectual development, borderline intellectual functioning,emotional disorders INTRODUCTION Antenatal exposure of the thyroid gland to ionizing radiation is one of the factors that might unfavorably influence on the intellectual development. Radiation affecting of the thyroid gland leads to involvement of other endocrine glands in the pathological process through the thyroid-hypophysis-hypothalamus system (Lyaginskaya A.M. et al.,1992). Among the unfavorable psychosocial factors capable to affect the mental health of children there are to be taken into account the effects of forced relocation or adaptation to new conditions of living in areas exposed after the contamination. These factors lead to psycho-emotional stress in parents,and affected family relations (Kolominsky Ya.I., Igumnov S.A., 1995). Thus in estimating the influence of the Chernobyl nuclear power plant accident on the psychological development of persons,it is necessary to take into account both ante- and postnatal irradiation,nonradiation burdening exogenous and psychosocial factors (Nyagu A.I. et al., 1996). The present study was concerning the clinical- 08ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ02 ｨｴｨｨｨｰ0609ｨｨ01ｨｪ06ｨｦ (0204) ｨｰ ｨ ｨｺｨｰ060806ｨｬ, ｨ ｨｪ04ｨｬ 06ｨｺｨ 04ｨ ｨｰｨｹ ｨｪ0200ｨ ｨｰｨｨ09ｨｪ ｨｨ07ｨｪｨｨ02 ｨｪｨ ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ ｨｦ09ｨｰ09ｨｨ02 ｨｪｨ ｨ 01ｨｨ06ｨｨ0406ｨｰ ｨｦ0601ｨ ｨｬ060302ｨｰ 0709ｨｨｨｰｨｹ0907 ｨｪｨ ﾂｨ 05ｨｹｨｪ04ｨｬ ｨｪ06ｨｬ ﾂ02ｨｪｨｨ ｨ ｨｰ ｨｨ- ﾂ0209ｨｺｨｨｨｦ ｨｨ 0108ｨｮ00ｨｨ01 05ｨｪ0106ｨｺ08ｨｨｨｪｨｪ ﾂ ｨｨ09ｨｰ02ｨｬｨｮ ｨｨ070600ｨｨ04-00ｨｨ0706ｨｰｨ 05ｨ ｨｬｨｮ09 (090700ｨｨｨｪ09ｨｺｨ ｨｨ 0906ｨ 09ｨｰ.,1992) ｨｨ ｨｪ02ｨ 05ｨ ｨｨ07ｨｰｨｪ ｨｨ ｨｨｨ 05ｨｹｨｪ ｨ ｨｺｨｰ , ｨ ｨｪ ｨｺｨ 04ｨ ｨｰｨｹ 0905ｨｨ07ｨｪｨｨ02 ｨｪｨ 0709ｨｨ01ｨｨ ﾂ0209ｨｺ ｨｹ ｨｰ02ｨｦ, ｨｪ0205ｨｹ0407 ｨｪ02 ｨｮ ﾂｨｨｨｰ0409ｨ ｨｰｨｹ ｨｺｨｰ ｨｪｨｮ030102ｨｪｨｪ06ｨｦ ｨｬｨｨ0008ｨ 02ｨｨｨｨ ｨｨ05ｨｨ 0708ｨｨ ｨ 0502ｨｪｨｨ07 ｨｺ ｨｪ060904ｨｬ ｨｮ ｨｨ07ｨｬ 03ｨｨ04ｨｪｨｨ ｨｪｨ ｨｰ08ｨ 01ｨ 0903ｨｨ01 ｨｰ020808ｨｨｨｰ0608ｨｨ ｨｰｨｨ 00ｨ ｨｺｨｰ ｨｨ ｨｰ ｨｺ 0709ｨｨ010605ｨｬ0602ｨｨ06ｨｪｨ 05ｨｹｨｪ06ｨｬｨｮ 09ｨｰ ｨｮ ｨｮ ｨｨｨｰ020502ｨｦ ｨｨ ｨｪｨ 08ｨｮ0302ｨｪｨｨ ｨｬ02ｨｦｨｪ ｨ ｨｨｨｬ0606ｨｰｨｪ060302ｨｪｨｨｨｦ ( ｨｬｨｨｨｪ09ｨｺｨｨｨｦ ,0600ｨｮｨｬｨｪ ,1995). 0308ｨｨ ｨｪｨｺ ｨｨ07ｨｪｨｨ07 ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ ｨ 09ｨ 08ｨｨｨｨ ｨｪｨ 0709ｨｨ ｨｨ ﾂ0209ｨｺ ｨ 0409ｨｨｨｰｨｨ02 05ｨｨ02, ｨｨ ｨｦ09ｨｰ09ｨｨ06 09 ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ06ｨｬ ｨｨ060102, ｨｪ0206ｨ ｨｨｨｬ06 ｨｮ ﾂｨｨｨｰ0409ｨ ｨｰｨｹ ｨｪ02 ｨｰ0605ｨｹｨｺ06 ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ0602 ｨｨ ｨｰｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ02 ｨｨ ｨｪ0208ｨ 01ｨｨｨ 02ｨｨ06ｨｪｨｪ ｨｰ070006ｨｴｨ 06ｨｴｨｨ02 00ｨ ｨｺｨｰ060804, ｨｪ06 ｨｨ 0709ｨｨ ｨｨｨ 05ｨｹｨｪ ｨ ｨｺｨｰ (010700ｨｮ ｨｨ 0906ｨ 09ｨｰ.,1996). 108

2 13psychological estimation if intellectual progress in children exposed to antenatal exposure to ionizing radiation after the Chernobyl NPP accident. Reconstruction of individual radiation doses of antenatal exposure on thyroid and whole body external irradiation was held under study conduction with application within further clinicaldosimetry analysis. Igumnov, Drozdovitch / International Journal of Radiation Medicine 2004, 6(1-4): ｨ 09ｨｰ0607ｨｴ0202 ｨｨ ｨ ｨｪｨｨ ｨｴ02ｨｪ06 ｨｺ05ｨｨｨｪｨｨｨｺ ｨｨ ｨｨ ﾂ0209ｨｺ06ｨｦ ｨｪｨｺ02 ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ ｨｰ02ｨｦ, ｨｨ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ06ｨｬｨｮ 06ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｰ09ｨｨ02 ｨ 09ｨ 08ｨｨｨｨ ｨｪｨ ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ ｨｨ ｨ ｨｪｨｨ ｨｮｨｴ0209ｨｰ090502ｨｪｨ 0802ｨｺ06ｨｪ09ｨｰ08ｨｮｨｺ02ｨｨ07 ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｨ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ07,ｨｺ06ｨｰ ｨ 0405ｨｨ ｨｨ ｨｹ040609ｨ ｨｪ ｨｺ05ｨｨｨｪｨｨｨｺ ｨｨｨｬ02ｨｰ08ｨｨ ﾂ0209ｨｺ ｨ ｨｪｨ 05ｨｨ04ｨ. OBJECTIVE OF THE STUDY * prospective investigation of the intellectual development at the age of 6-7 years till age years among persons exposed in utero following the Chernobyl accident; * comparative analysis of the data obtained as a result of the clinical and psychological investigation and dosimetry data; * investigation of the role of unfavorable socialpsychological and social-cultural factors stipulated by the Chernobyl accident and its consequences in the genesis of the disturbances of intellectual development of exposed children. MATERIALS AND METHODS Participants ﾁ * ｨｺｨｰｨｨ09ｨｪ0602 ｨｨ ｨ ｨｪｨｨ02 ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ07 05ｨｨ02, ｨｨ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ06ｨｬｨｮ 06ｨ 05ｨｮ- ﾂ02ｨｪｨｨ ｨｮ05ｨｹｨｰｨ ｨｰ02 ｨ 09ｨ 08ｨｨｨｨ ｨｪｨ ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ , ｨ 09ｨｰ02 06ｨｰ ｨｰ; * 0908ｨ 09ｨｪｨｨｨｰ0205ｨｹｨｪ04ｨｦ ｨ ｨｪｨ 05ｨｨ04 01ｨ ｨｪｨｪ0401, ｨｮ ﾂ02ｨｪｨｪ ｨｺ05ｨｨｨｪｨｨｨｺ ｨｨ ｨｨ ﾂ0209ｨｺ ｨｨ ｨ ｨｪｨｨ07, ｨｨ ｨｨｨｬ02ｨｰ08ｨｨ ﾂ0209ｨｺｨｨ01 01ｨ ｨｪｨｪ0401; * ｨｪｨｺｨ ｨｨ ｨｪ02ｨ 05ｨ ｨｨ07ｨｰｨｪ ｨｨ ｨｨ ﾂ0209ｨｺｨｨ01 ｨｨ ｨｨｨ 05ｨｹｨｪ ｨｬ060008ｨ 00ｨｨ ﾂ0209ｨｺｨｨ01 00ｨ ｨｺｨｰ , 06ｨ ｨｮ ｨｪｨｪ0401 ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ ｨ 09ｨ 08ｨｨ02ｨｦ ｨｨ ｨｰ09ｨｨ07ｨｬｨｨ, ｨｨ ｨｪｨｨｨｨ ｨｪｨ 08ｨｮ0302ｨｪｨｨｨｦ ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ07 ｨｮ 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ ｨｰ02ｨｦ ﾂｨ 09ｨｰｨｪｨｨｨｺｨｨ ｨｨ ｨ ｨｪｨｨ07 The exposed group was of 250 persons, born between May 1986 and February During the Chernobyl accident their pregnant mothers lived in the highly contaminated settlements where 137 Cs soil deposition densities ranged from 555 to 18,500 kbq m -2. The control group was formed by random selection and consisted of 250 persons had been born between May 1986 and February Their mothers had constantly lived in settlements with low and mild contamination (from 2 to 200 kbq m -2 of 137 Cs). The distribution of persons according to sex and the period of gestation at the time of the Chernobyl accident is given in table 1. Also there were no relevant distinctions of social status of parents of persons belonging to the exposed and control group. 02ｨ 05ｨｮ ﾂ02ｨｪｨｪｨ ｨｮ0707ｨ ｨｰ060705ｨ ｨｨ ｨｨ02, ｨｪｨｪ ｨｨ ｨｬｨ ｨ 05ｨｹ ｨ 06ｨｰ ｨｬｨ ｨｰ020802ｨｦ, ｨｺ06ｨｰ ｨｪｨ ｨｬ06ｨｬ02ｨｪｨｰ ｨ 09ｨ 08ｨｨｨｨ ｨｪｨ ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ ｨｨ09ｨ 05ｨｨ ｨｪｨ ｨｺ06ｨｪｨｰ080605ｨｨ08ｨｮ02ｨｬ0401 ｨｰ020808ｨｨｨｰ0608ｨｨ ｨｮ080609ｨｪ02ｨｬ ｨ ｨｪ02ｨｪｨｨ ﾂ09 Cs ｨｺ09ｨｺ ｨｬ ｨｪｨｰ080605ｨｹｨｪｨ ｨｮ0707ｨ ｨ 0405ｨ ｨｬｨｨ080609ｨ ｨｪｨ ｨｬ02ｨｰ060106ｨｬ 0905ｨｮ ﾂｨ ｨｦｨｪ06ｨｦ 0904ｨ 0608ｨｺｨｨ ｨｨ ｨｰ060705ｨ ｨｨ ｨｰ02ｨｦ, ｨｪｨｪ ｨｨ ｨｬｨ ｨ 05ｨｹ ｨ ｨｬｨ ｨｰ0208ｨｨ ｨｰ0607ｨｪｨｪ ｨｨ09ｨ 05ｨｨ 09 08ｨ ｨｦ06ｨｪｨ ｨｪｨｨ04ｨｺｨｨｨｬ ｨｮ080609ｨｪ02ｨｬ 08ｨ 01ｨｨ06ｨ ｨｺｨｰｨｨ09ｨｪ ｨ ｨｪ02ｨｪｨｨ07 (2-200 ｨｺ09ｨｺ ｨｬ Cs). 04ｨ ｨｪｨｨ ｨｰ02ｨｦ 09 04ｨ 09ｨｨ09ｨｨｨｬ0609ｨｰｨｨ 06ｨｰ ｨ ｨｨ ｨｺｨ ｨｰｨ 02ｨｨｨｨ 09 ｨｬ06ｨｬ02ｨｪｨｰ ｨ 09ｨ 08ｨｨｨｨ ｨｪｨ ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ ｨｰｨ ｨｪ06 09 ｨｰｨ ｨ 05ｨｨ ｨｰ09ｨｮｨｰ09ｨｰ090609ｨ 05ｨｨ ｨｰｨ ｨｺ ｨｰ ｨｪ ｨ 0405ｨｨ ﾂｨｨ ｨｨｨ 05ｨｹｨｪ06ｨｬ 09ｨｰｨ ｨｰｨｮ ｨｨｨｰ020502ｨｦ 0102ｨｰ02ｨｦ 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ0707. AGE AND SEX DISTRIBUTIONS OF PERSONS OF EXPOSED AND CONTROL GROUPS Gestation Number of persons in Comparison between period, exposed group control group groups, p weeks male female total male female total in gender total 0ｨC ｨC ｨC > Total ﾓ1 TABLE

3 Estimation of the period of gestation at the time of the Chernobyl accident was based upon the inferred first day of the last menstrual period and has been calculated with the modified formula of Schull et al. (1988). The mean duration of gestation was assumed as 280 days (assayed since the last menstrual cycle onset). The day of birth was obtained by interview with the mothers of the persons. To obtain the age after fertilization, 14 days have been subtracted from the term of gestation at the time of the Chernobyl accident ｨｺ ｨｰｨ 02ｨｨｨｨ 09 ｨｬ06ｨｬ02ｨｪｨｰ ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ ｨｺｨ ｨｰｨ 09ｨｰ ﾂｨｨ ｨｨ 0706 ｨｬ0601ｨｨ00ｨｨ02ｨｨ080609ｨ ｨｪｨｪ06ｨｦ ｨｬｨｮ0502, ｨｪｨｪ06ｨｦ W. Schull et al. (1989), 07ｨｮｨｰ02ｨｬ 0904 ﾂｨｨｨｰｨ ｨｪｨｨ07 ｨｨ ｨｮｨｰ06ｨｺ ( ｨｪ ｨｨｨｰ0205ｨｹｨｪ0609ｨｰｨｹ ｨ ｨｬ02ｨｪｨｪ0609ｨｰｨｨ, ｨｨ04ｨｬ020802ｨｪｨｪｨ ｨｪ07 ｨｪｨ 09ｨｰｨｮ070502ｨｪｨｨ ｨｪ ｨｬ02ｨｪ09ｨｰ08ｨｮｨ 05ｨｹｨｪ ｨｨｨｺ05ｨ ) ｨｨ0601ｨ ｨｬ02ｨｪｨｨ ｨｬ020301ｨｮ ｨｬ06ｨｬ02ｨｪｨｰ06ｨｬ ｨｺｨ ｨｰｨ 09ｨｰ ｨｨ 01ｨ ｨｰ06ｨｦ ｨｪｨｨ ｨ 02ｨｪｨｺｨ ｨｺｨ ｨ ｨｬ02ｨｪｨｪ0609ｨｰｨｨ 09 ｨｬ06ｨｬ02ｨｪｨｰ ｨ 09ｨ 08ｨｨｨｨ 04ｨ ｨｰ02ｨｬ 0904 ﾂｨｨｨｰｨ 05ｨｨ 14 01ｨｪ02ｨｦ ｨｪ020902ｨｪｨｨ ｨ 09ｨｺｨｨ ｨｪｨ ｨｬ07 ｨｬ020301ｨｮ ｨｪｨ 09ｨｰｨｮ070502ｨｪｨｨ02ｨｬ ｨｪ ｨｬ02ｨｪ09ｨｰ08ｨｮｨ 05ｨｹｨｪ ｨｨｨｺ05ｨ ｨｨ 0609ｨｮ050702ｨｨ02ｨｦ ｨｰ ｨｪｨｨ02ｨｬ 07ｨｦ0202ｨｺ0502ｨｰｨｺｨｨ. Dosimetry Thyroid doses from iodine intake were reconstructed on the basis of results of 131 I activity direct measurements in thyroid (if such data were available from measurements held in mothers of children included in the study),or from an 131 I environmental transfer model adapted to the local Belarusian conditions (Drozdovitch V.V. et al., 1997). The regional-specific values were received for the following radio-ecological parameters according to the respective local conditions: (a) ratio between activities of 131 I and 137 Cs in ground deposition; (b) initial interception of 131 I by vegetation; (c) elimination rate of 131 I from grass and milk due to airing and growth; and (d) transfer factor for 131I from grass to cow's milk. Model was validated with the received results validity estimation for 292 settlements where average thyroid radiation doses calculated according to the model were compared to the values of direct 131 I activity measurements in thyroid gland (Gavrilin Yu.I. et al.,1999). For 95% of these settlements the results of the radio-ecological model and the measurements agree within a factor of 2.5 (Drozdovitch V.V.,1999). Thyroid doses for persons exposed in utero were estimated from results of individual thyroid radiation dose estimates for the mother, and from a transfer coefficient from maternal radiation dose to the fetal one with taking into account the period of gestation at the time of exposure (Zvonova I.A., Balonov M.I., 1993). To estimate the individual thyroid doses the following information about the life-style of the mother during the iodine period was obtained by personal interview: (a) consumption rates of fresh milk and diary products; (b) origin of consumed foodstuffs; (c) cessation of consumption of locally produced foodstuffs; (d) place of residence at the time of accident; (e) migration during April-May 1986; (f) stable iodine prophylaxis, etc. Antenatal external doses from radionuclides deposited onto ground were reconstructed also for persons of the exposed and control group. Reconstruction has been performed based on the values of dose rate in uterus per unit of radionuclide deposition density (Jacob P. et al., 1988), radionuclide composition in fallout measured in different ｨｨｨｬ02ｨｰ08ｨｨ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｰ ｨｰｨｮ070502ｨｪｨｨ07 ｨｦ0601ｨ ｨ 0405ｨｨ 0802ｨｺ06ｨｪ09ｨｰ08ｨｮｨｨ080609ｨ ｨｪ04 ｨｪｨ 0609ｨｪ ｨｮ05ｨｹｨｰｨ ｨｰ ｨｬ0401 ｨｨ04ｨｬ020802ｨｪｨｨｨｦ ｨ ｨｺｨｰｨｨ09ｨｪ0609ｨｰｨｨ (020905ｨｨ 05ｨｰｨｨ ｨｨ04ｨｬ020802ｨｪｨｨ07 ｨ 0405ｨｨ ｨｪ ｨｬｨ ｨｰ020802ｨｦ 05ｨｨ02, 09ｨｺ0506 ﾂ02ｨｪｨｪ ｨｨ ｨ ｨｪｨｨ02) ｨｨ05ｨｨ ｨｨ ｨｹ04ｨｮ07 ｨｬ ｨｹ ｨｪ0609ｨ 131 I 09 06ｨｺ08ｨｮ03ｨ 06ｨｴ02ｨｦ , ｨ 01ｨ 07ｨｰｨｨ080609ｨ ｨｪｨｪｨｮ06 ｨｺ ｨｬ0209ｨｰｨｪ04ｨｬ ｨｮ ｨｨ07ｨｬ (Drozdovitch V.V. et al.,1997) ｨｨ06ｨｪｨ 05ｨｹｨｪ ｨｨ00ｨｨ ﾂ0209ｨｺｨｨ02 04ｨｪｨ ﾂ02ｨｪｨｨ07 ｨ 0405ｨｨ ｨｮ ﾂ02ｨｪ ｨｮ06ｨｴｨｨ01 08ｨ 01ｨｨ0605ｨｺ ｨｨ ﾂ0209ｨｺｨｨ01 07ｨ 08ｨ ｨｬ02ｨｰ ｨｬ ｨｨ: 1) 06ｨｰｨｪ060302ｨｪｨｨ02 ｨ ｨｺｨｰｨｨ09ｨｪ0609ｨｰ02ｨｦ 131 I ｨｺ 137 Cs ｨ 0102ｨｪｨｨ0701; 2) 00ｨ ｨｺｨｰ0608 ｨｪｨ ﾂｨ 05ｨｹｨｪ ｨｮ ｨ ｨｪｨｨ I 08ｨ 09ｨｰｨｨｨｰ0205ｨｹｨｪ0609ｨｰｨｹ06; 3) 09ｨｺ ｨｰｨｹ 06 ﾂｨｨ09ｨｰｨｺｨｨ 08ｨ 09ｨｰｨｨｨｰ0205ｨｹｨｪ0609ｨｰｨｨ 06ｨｰ 131 I ｨｨ04-04ｨ ｨｰ08ｨｨ09ｨ ｨｪｨｨ07 ｨｨ ｨｰｨ ; 4) ｨｺ ｨｨ02ｨｨ02ｨｪｨｰ ｨ 131 I 09 ｨｬ060506ｨｺ06 ｨｺ ｨｨ00ｨｨｨｺｨ 02ｨｨｨｨ ｨｬ ｨｨ ｨｨ ｨｪｨｺｨｨ ｨｰ ｨｪ0609ｨｰｨｨ ｨｮ ﾂｨ 02ｨｬ ｨｮ05ｨｹｨｰｨ ｨｰ ｨｪｨ ｨｪｨｪ ｨｮｨｪｨｺｨｰ ｨｪ ｨ 09ｨｪ02ｨｪｨｨ ｨｪｨｨ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ,08ｨ 0909 ﾂｨｨｨｰｨ ｨｪｨｪ ｨｬ ｨｨ, ｨｨ ｨｪ02ｨｪｨｪ ｨｮ05ｨｹｨｰｨ ｨｰｨ ｨｬ ｨｬ0401 ｨｨ04ｨｬ020802ｨｪｨｨｨｦ ｨ ｨｺｨｰｨｨ09ｨｪ0609ｨｰｨｨ 131 I (Gavrilin Yu.I. et al., 1999) % ｨｪｨ ｨｪｨｪ ｨｮｨｪｨｺｨｰ ｨｮ05ｨｹｨｰｨ ｨｰ04 08ｨ 09 ﾂ02ｨｰｨ 0706 ｨｬ ｨｨ ｨｨ ｨｬ04ｨｬ ｨｨ04ｨｬ020802ｨｪｨｨ07ｨｬ ｨ 09ｨｮ06ｨｰ ｨ 01 00ｨ ｨｺｨｰ0608ｨ 2,5 (Drozdovitch, V.V. 1998) ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ06 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ ｨｨ ｨｪｨｨ09ｨ 05ｨｨ09ｨｹ ｨｪｨ 0609ｨｪ ｨｮ05ｨｹｨｰｨ ｨｰ ｨｺ06ｨｪ09ｨｰ08ｨｮｨｺ02ｨｨｨｨ ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｬｨ ｨｰ020802ｨｦ ｨｨ ｨｺ ｨｨ02ｨｨ02ｨｪｨｰ ｨ 06ｨｰ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｬｨ ｨｰ0208ｨｨ ｨｺ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨ 09 ｨｮ ﾂ02ｨｰ06ｨｬ ｨｺｨ ｨ ｨｬ02ｨｪｨｪ0609ｨｰｨｨ 09 ｨｬ06ｨｬ02ｨｪｨｰ 06ｨ 05ｨｮ ﾂ02ｨｪｨｨ07 (Zvonova I.A., Balonov M.I., 1993) ｨｪｨｺｨｮ ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｨ05ｨｨ ｨｪｨ 0609ｨｪ0609ｨ ｨｪｨｨｨｨ 01ｨ ｨｪｨｪ ｨ 08ｨ 04ｨ 03ｨｨ04ｨｪｨｨ ｨｬｨ ｨｰ0208ｨｨ 09 ｨｰ02 ﾂ02ｨｪｨｨ02 ｨｦ0601ｨｪ ｨｨ0601ｨ,070605ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 07ｨｮｨｰ02ｨｬ ｨｪｨ 05ｨｹｨｪ : 1) ｨｺ0605ｨｨ ﾂ0209ｨｰ ｨｰ0802ｨ ｨｬ ｨｬ060506ｨｺｨ ｨｨ ｨｬ ﾂｨｪ ｨｮｨｺｨｰ0609 2) ｨｨ09ｨｰ06 ﾂｨｪｨｨｨｺｨｨ 0706ｨｰ0802ｨ ｨｬ ｨｮｨｺｨｰ0609; 3) 01ｨ ｨｰｨ ｨｺ08ｨ ｨｴ02ｨｪｨｨ07 ｨｮ0706ｨｰ0802ｨ 0502ｨｪｨｨ ｨｮｨｺｨｰ ｨｨｨｰｨ ｨｪｨｨ07 ｨｬ0209ｨｰｨｪ ｨｨ ｨｰ09ｨ ; 4) ｨｬ0209ｨｰ06 03ｨｨｨｰ0205ｨｹ09ｨｰ09ｨ 09 ｨｬ06ｨｬ02ｨｪｨｰ ｨ 09ｨ 08ｨｨｨｨ; 5) ｨｰ02 ﾂ02ｨｪｨｨ02 ｨ ｨｬｨ ; 6) ｨｦ0601ｨｪｨ ｨｨ05ｨ ｨｺｨｰｨｨｨｺｨ ｨｨ ｨｨ ｨｪ0609ｨｪ06ｨｦ ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ0707 ｨ 0405ｨｨ ｨｰｨ ｨｺ ｨｺ06ｨｪ09ｨｰ08ｨｮｨｨ080609ｨ ｨｪ04 ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ07 06ｨｰ 08ｨ 01ｨｨ06ｨｪｨｮｨｺ05ｨｨ010609, ｨ 0903ｨｨ01 ｨｪｨ ｨｪ0609ｨｰｨｹ 0706 ﾂ0904, 09 ｨｨ ｨｹ040609ｨ ｨｪｨｨ02ｨｬ 04ｨｪｨ ﾂ02ｨｪｨｨｨｦ ｨｬ06ｨｴｨｪ0609ｨｰｨｨ , ｨｴ02ｨｪｨｪ06ｨｦ ｨｬｨ ｨｰ0208ｨｨｨｪ09ｨｺ06ｨｦ ｨｬｨ ｨｰｨｺ06ｨｦ,ｨｪｨ 0201ｨｨｨｪｨｨ02ｨｮ ｨｰｨｪ0609ｨｰｨｨ 04ｨ ｨｪ02ｨｪｨｨ07 (Jacob P. et al.,1988),090606ｨｰｨｪ060302ｨｪｨｨｨｦ 08ｨ 01ｨｨ06ｨｪｨｮｨｺ05ｨｨ ｨ 0102ｨｪｨｨ ｨ 04ｨｪ ｨｨ06-110

4 13territories, and individual behavior of mothers after the accident. The last one included: (a) residence place at the time of accident; (b) migration within period since the accident till childbirth; (c) type of dwelling; (d) time spent outdoors. Igumnov, Drozdovitch / International Journal of Radiation Medicine 2004, 6(1-4): ｨｪｨ 01 ｨｨ 01ｨ ｨｪｨｪ ｨ 06ｨ 08ｨ ｨｨ04ｨｪｨｨ ｨｬｨ ｨｰ0208ｨｨ ｨ 09ｨ 08ｨｨｨｨ: 1) ｨｬ0209ｨｰ06 03ｨｨｨｰ0205ｨｹ09ｨｰ09ｨ 09 ｨｬ06ｨｬ02ｨｪｨｰ ｨ 09ｨ 08ｨｨｨｨ; 2) ｨｰ02 ﾂ02ｨｪｨｨ ｨ 09ｨ 08ｨｨｨｦｨｪ ｨｨ0601ｨ ｨｪｨｨ ｨ 02ｨｪｨｺｨ ; 3) ｨｰｨｨ ｨ ｨｪｨｨ07, 09 ｨｺ06ｨｰ060806ｨｬ ｨｨ09ｨ 05ｨ ｨ ｨｬ02ｨｪｨｪｨ 07; 4) ｨｬ02ｨｪｨｨ, ｨｪｨｪ06ｨｬ ｨｪｨ 06ｨｰｨｺ0804ｨｰ06ｨｬ ｨｮ0102. Psychological examination The intellectual development of these persons was examined by means of psychological testing using the modified Wechsler Intelligence Scale for Children - WISC-III-UK (Wechsler D., 1992). We also applied clinical-psychological and socialpsychological methods: studying of microsocial surrounding of persons and comparative analysis conduction of the education level of their parents (i.e. incomplete secondary,secondary,special secondary and higher education). RESULTS AND DISCUSSION Dosimetry For 64 persons from the exposed group and for 72 persons from the control group a zero thyroid dose from 131 I mother's intake was estimated. It is mainly due to the fact that gestation age of the fetus at the time of the accident was less than 10 weeks and there was no uptake of 131 I by undeveloped thyroid. The mean internal thyroid doses from 131 I were estimated to be 390 ﾀ550 and 35 ﾀ65 mgy in exposed and control group respectively, medians of distributions in both groups and 14 mgy respectively. In exposed group the maximal individual internal antenatal thyroid dose was 4,100 mgy. The mean doses from external exposure to fetus of 10 ﾀ3 mgy and 0.2 ﾀ0.4 mgy were estimated in exposed and control group, accordingly. Medians of external thyroid dose distribution in exposed and control group were 6 and 0.1 mgy respectively. Among persons of the exposed group the maximal individual external antenatal thyroid dose was 91 mgy. IQ test results At the age 6-7 years persons of the exposed group had a lower mean full-scale Intelligence Quotient (IQ) compared to the control group (89.6 ﾀ10.2 vs ﾀ10.5,p=0.007). We found that persons of the exposed group had a relatively more cases of a low average range of full-scale IQ (IQ=80-89) as compared to the control group (92 persons (36.8%) vs. 66 persons (26.4%) in control group, P=0.012). Clinically the children having low average level of intellectual norm were characterized by moderate disorders of cognitive processes,poor motivation to school education and lack of intellectual prerequisites (active attention, short-term memory, constructional functions, etc.). There were no statistically significant differences between mean IQs 0309ｨｨ ｨｨ ﾂ0209ｨｺ0602 ｨｨ ｨ ｨｪｨｨ02 06ｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ ｨｪｨｨ09ｨ 05ｨｨ 07ｨｮｨｰ02ｨｬ 0709ｨｨ ｨｨ ﾂ0209ｨｺ ｨｰ0209ｨｰｨｨ080609ｨ ｨｪｨｨ ｨ 01ｨ 07ｨｰｨｨ080609ｨ ｨｪｨｪ06ｨｦ ｨｨｨｨ 01ｨｺｨ ｨｺ ｨ ｨｨ04ｨｬ020802ｨｪｨｨ07 ｨｨｨｪｨｰ ｨｺｨｰｨ 0102ｨｰ02ｨｦ (Wechsler Intelligence Scale for Children-WISC-III- UK) (Wechsler D., 1992) ｨｹ040609ｨ 05ｨｨ ｨｰｨ ｨｺ0302 ｨｺ05ｨｨｨｪｨｨｨｺ ｨｨ ｨｨ ﾂ0209ｨｺｨｨ02 ｨｨ ｨｨｨ 05ｨｹｨｪ ｨｨ ｨｨ ﾂ0209ｨｺｨｨ02 ｨｬ02ｨｰ060104: ｨｨ04ｨｮ ﾂ02ｨｪｨｨ02 ｨｬｨｨｨｺ ｨｨｨ 05ｨｹｨｪ ｨｺ08ｨｮ0302ｨｪｨｨ07 ｨｨ 0908ｨ 09ｨｪｨｨｨｰ0205ｨｹｨｪ04ｨｦ ｨ ｨｪｨ 05ｨｨ04 06ｨ 08ｨ ｨ ｨｰ0205ｨｹｨｪ ｨｮ080609ｨｪ ｨｨｨｰ020502ｨｦ (ｨｪ0204ｨ ｨｺ06ｨｪ ﾂ02ｨｪｨｪ ｨｪ0202, ｨｪ0202, ｨｪ ｨｨｨ 05ｨｹｨｪ0602, ｨ 08ｨ ｨ ｨｪｨｨ02) ｨｨｨｬ02ｨｰ08ｨｨ ｨｰ02ｨｦ ｨｨ ｨｪ0609ｨｪ06ｨｦ 0008ｨｮ ｨｨ ｨｰ02ｨｦ ｨｨ04 ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ ｨｺ06ｨｪ09ｨｰ08ｨｮｨｨ080609ｨ ｨｪｨ ｨｪｨｮ050209ｨ ｨ 09ｨｪｨｮｨｰ0802ｨｪｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ I. 06ｨｰ06 06ｨ ｨｮ ｨｪ06, ｨｪ0609ｨｪ06ｨｬ,ｨｰ02ｨｬ 00ｨ ｨｺｨｰ06ｨｬ, ﾂｨｰ ｨｺ ｨｰｨ 02ｨｨｨｨ ｨｪｨ ｨｬ06ｨｬ02ｨｪｨｰ ｨ 09ｨ 08ｨｨｨｨ ｨｪｨ ﾁ ｨｰｨ ｨｬ02ｨｪ ｨｪ ｨｹ ｨｨ ｨｪ02 ｨ ｨｰｨｮ070502ｨｪｨｨ07 08ｨ 01ｨｨ06ｨ ｨｺｨｰｨｨ09ｨｪ ｨｦ0601ｨ 09 ｨｪ0208ｨ 0409ｨｨｨｰｨｮ ｨ ｨｪｨｨ ｨ 05ｨｮ ﾂ02ｨｪｨｨ I ｨｪ0609ｨｪ06ｨｦ ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ0707ｨ ｨｰｨ 09ｨｨ05ｨｨ,090606ｨｰ0902ｨｰ09ｨｰ0902ｨｪｨｪ06,390 ﾀ550 ｨｬ0108 ｨｨ 35 ﾀ65 ｨｬ0108,ｨｬ0201ｨｨｨ ｨｪ04 08ｨ ｨｪｨｨ ｨｨ 14 ｨｬ ｨｨ 05ｨｨ ｨｪ0609ｨｪ06ｨｦ 0008ｨｮ ｨｬｨ ｨｺ09ｨｨｨｬｨ 05ｨｹｨｪｨ 07 ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪｨ ｨｪｨ ｨｰｨ 05ｨｹｨｪｨ ｨ 06ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｰｨ 09ｨｨ05ｨ 4100 ｨｬ ｨｪｨｨ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ07 ｨｪｨ ﾀ13 ｨｬ0108 ｨｨ 0,2 ﾀ0,4 ｨｬ0108 ｨ 0405ｨｨ ｨｪ02ｨｪ ｨｨ ｨｪ0609ｨｪ06ｨｦ ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ ｨｨｨ ｨｪｨ 08ｨ ｨｪｨｨ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｰｨ 09ｨｨ05ｨ 6 ｨｨ 0,1 ｨｬ ｨｨ ｨｪ0609ｨｪ06ｨｦ ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ ｨｨ 05ｨｨ ｨｪ0609ｨｪ06ｨｦ 0008ｨｮ ｨｬｨ ｨｺ09ｨｨｨｬｨ 05ｨｹｨｪｨ 07 ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪｨ 07 ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪｨ ｨ 09ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｰｨ 09ｨｨ05ｨ 91 ｨｬ ｨｰ04 ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ ｨｰｨｪ02ｨｬ ｨ 09ｨｰ02 05ｨｨ02ｨ 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨｨｨｬ0205ｨｨ ｨ ｨｪｨｨ04ｨｺｨｨｨｦ ｨｪｨｨｨｦ 06ｨ ｨｴｨｨｨｦ ｨｺ ｨｨ02ｨｨ02ｨｪｨｰ ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ0609ｨｰｨｨ (IQ) ｨ 09ｨｪ02ｨｪｨｨｨｨ 09 ｨｺ06ｨｪｨｰ ｨｬ (89,6 ﾀ10,2 ｨｨ 92,1 ﾀ10,5; 08=0,007) ｨｪ06 ｨｰｨ ｨｺ ｨｰｨｪ0609ｨｨｨｰ0205ｨｹｨｪ ｨ 05ｨ 01ｨ ｨｪｨｨ ｨｮ ﾂｨ 0209 "ｨｪｨｨ03ｨｪ ｨｮ080609ｨｪ07 ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ06ｨｦ ｨｪ0608ｨｬ04" (IQ=80-89) 09 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ070702, ｨ 09ｨｪ02ｨｪｨｨｨｨ 09 ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ (92 (36,8%) ｨｨ ｨｰ02ｨｦ (26,4%),090606ｨｰ0902ｨｰ09ｨｰ0902ｨｪｨｪ06; 08=0,012). 0805ｨｨｨｪｨｨ ﾂ0209ｨｺｨｨ 0102ｨｰｨｨ 09 "ｨｪｨｨ03ｨｪｨｨｨｬ ｨｮ080609ｨｪ02ｨｬ ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ06ｨｦ ｨｪ0608ｨｬ04" 01ｨ 08ｨ ｨｺｨｰ0208ｨｨ040609ｨ 05ｨｨ09ｨｹ ｨｮｨｬ020802ｨｪｨｪ06ｨｦ 04ｨ ｨｺ06ｨｦ ｨｬｨｨ080609ｨ ｨｪｨｨ ｨｪｨ 09ｨ ｨｰ0205ｨｹｨｪ , ｨｪｨｨ04ｨｺｨｨｨｬ ｨｮ080609ｨｪ02ｨｬ ｨｬ06ｨｰｨｨ09ｨ 02ｨｨｨｨ ｨｺ 03ｨｺ0605ｨｹｨｪ06ｨｬｨｮ 06ｨ ｨｮ ﾂ02ｨｪｨｨ06 ｨｨ ｨｪ ｨｰｨ ｨｰ06 ﾂｨｪ04ｨｬ ｨｮ080609ｨｪ02ｨｬ 08ｨ 0409ｨｨｨｰｨｨ07 " ｨｺ ｨｨｨｪｨｰ ｨｺｨｰｨ " (ｨ ｨｺｨｰｨｨ09ｨｪ ｨｪｨｨｨｬｨ ｨｪｨｨ07, ｨｺ08ｨ ｨｰｨｺ ｨｬ02ｨｪｨｪ06ｨｦ 07ｨ ｨｬ07ｨｰｨｨ, ｨｺ06ｨｪ09ｨｰ08ｨｮｨｺｨｰｨｨ09ｨｪ ｨ ｨｺ09ｨｨ09ｨ ｨｨ ｨｰ.01.) ｨｪ06 09ｨｰｨ ｨｰｨｨ- 111

5 of the exposed and control groups at the age years (94.3 ﾀ10.4 vs ﾀ10.9, p=0.117), and at the age years (98.2 ﾀ10.7 vs ﾀ10.5, p=0.171). Dynamics of IQ in persons of exposed and control group from the age of 6-7 years till the age of years are given in table 2. 09ｨｰｨｨ ﾂ0209ｨｺｨｨ ｨｰ ｨｪ ｨ 0405ｨｨ ﾂｨｨｨｦ ｨｪｨｨ01 IQ 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ ｨ 09ｨｰ ｨｰ (94,3 ﾀ10,4 ｨｨ 95,8 ﾀ10,9; 08=0,117) ｨｨ ｨ 09ｨｰ ｨｰ (98,2 ﾀ10,7 ｨｨ 99,5 ﾀ10,5; 08=0,171). 02ｨｨｨｪｨ ｨｬｨｨｨｺｨ IQ 05ｨｨ02 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ ｨ 09ｨｰ02 06ｨｰ ｨｰ 0708ｨｨ ｨｪｨ 09 ｨｰｨ ｨ 05ｨｨ DYNAMICS OF INTELLECTUAL DEVELOPMENT IN PERSONS OF EXPOSED AND CONTROL GROUP FROM THE AGE OF 6-7, AND YEARS Full Scale Intelligence Quotient (IQ) Exposed group IQ , Persons of group at the age of 66ﾓ17 years 106ﾓ112 years 156ﾓ116 years* N % N % N % ﾝ 90 (average and high average range) (low average range) (borderline intellectual functioning) ﾜ 69 (exceptionally low range) Control group ﾝ 90 (average and high average range) (low average range) (borderline intellectual functioning) ﾜ 69 (exceptionally low range) Note. *Due to migration at the age years 5 persons had left the exposed group and 11 persons had left the control group. 0308ｨｨｨｬ02 ﾂｨ ｨｪｨｨ02. * ｨ ｨｬｨｨ0008ｨ 02ｨｨｨｨ 5 ﾂ ｨｺ 0706ｨｺｨｨｨｪｨｮ05ｨｨ 0609ｨｪ0609ｨｪｨｮ ｨｮ0707ｨｮ ｨｨ 11 ﾂ ｨｺ 0706ｨｺｨｨｨｪｨｮ05ｨｨ ｨｺ06ｨｪｨｰ080605ｨｹｨｪｨｮ ｨｮ0707ｨｮ. TABLE The distribution of IQ among persons of the exposed group for the gestational age at the time of the Chernobyl accident is given in table 3. No statistically significant differences in average IQ were found between subgroups. The distribution of average IQ among persons of the exposed group in relation to the thyroid dose from 131 I ranges is given in table 4. Subgroup of persons with thyroid doses over 1,000 mgy had relatively lower mean full-scale IQ compared to the entire exposed group at the age 6-7 years (86.5 ﾀ7.4 vs ﾀ10.2, p=0.162), at the age years (90.0 ﾀ7.9 vs ﾀ10.4, p=0.066), and at the age years (94.1 ﾀ9.4 vs ﾀ10.7, p=0.091). No significant correlation was also found in exposed group between individual thyroid dose from 131 I and IQ at the age of 6-7 years (r = -0.11; 08>0.1),at the age of years (r = -0.21; 08>0.1),and at the age of years (r = -0.29; 08>0.05) (figure 1) ｨ ｨｪｨｨ02 IQ 05ｨｨ02 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨ 09ｨｨ09ｨｨｨｬ0609ｨｰｨｨ 06ｨｰ ｨｺｨ ｨｰｨ 02ｨｨｨｨ ｨｪｨ ｨｬ06ｨｬ02ｨｪｨｰ ｨ 09ｨ 08ｨｨｨｨ ｨｪｨ ﾁ0208ｨｪ06ｨ 0405ｨｹ09ｨｺ06ｨｦ ｨｨ ｨｪ06 09 ｨｰｨ ｨ 05ｨｨ ｨｰｨ ｨｰｨｨ09ｨｰｨｨ ﾂ0209ｨｺｨｨ ｨｰ ｨｪ ｨ 0405ｨｨ ﾂｨｨｨｦ ｨｪｨｨ01 IQ ｨｬ020301ｨｮ ｨｮ0707ｨ ｨｬｨｨ ｨｪ02 ｨｪｨ ｨ ｨ ｨｹ. THE DISTRIBUTION OF IQ AMONG THE PERSONS OF THE EXPOSED GROUP IN RELATION TO THE GESTATIONAL AGE AT THE TIME OF THE CHERNOBYL ACCIDENT IQ ﾁ Gestational age, weeks Full scale IQ (mean ﾀ SD) N 66ﾓ17 years 106ﾓ112 years 156ﾓ116 years 06ﾓ ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ 10.0 > ﾀ ﾀ ﾀ 10.0 Total ﾀ ﾀ ﾀ 10.7 TABLE ｨ ｨｪｨｨ02 ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨｺｨ 04ｨ ｨｰ020502ｨｦ 05ｨｨ02 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨ 09ｨｨ09ｨｨｨｬ0609ｨｰｨｨ 06ｨｰ ｨｮ080609ｨｪ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ I 0708ｨｨ ｨｪ06 09 ｨｰｨ ｨ 05ｨｨ IQ 05ｨｨ02, ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｺ06ｨｰ ｨ 06ｨｰ 1000 ｨｬ0108, ｨ 0405ｨｨ 06ｨｰｨｪ0609ｨｨｨｰ0205ｨｹｨｪ06 ｨｪｨｨ0302, ﾂ02ｨｬ ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨｬ, ｨ 09ｨｰ ｨｰ (86,5 ﾀ7,4 ｨｨ 89,6 ﾀ10,2; 08=0,162), ｨｰ (90,0 ﾀ7,9 ｨｨ 94,3 ﾀ10,4; 08=0,066) ｨｨ ｨｰ (94,1 ﾀ9,4 ｨｨ 98,2 ﾀ10,7; 08=0,091) ｨｪ06 09ｨｰｨ ｨｰｨｨ09ｨｰｨｨ ﾂ0209ｨｺｨｨ ｨｰ ｨｪ06ｨｦ ｨｺ ｨｨ06ｨｪｨｪ06ｨｦ 04ｨ 09ｨｨ09ｨｨｨｬ0609ｨｰｨｨ ｨｬ020301ｨｮ ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪ06ｨｦ ｨｦ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ I ｨｨ IQ ｨ 09ｨｰ ｨｰ (r=-0,11; 08>0,1), ｨｰ (r=-0,21; 08>0,1) ｨｨ ｨｰ (r=-0,29; 08>0,05) (08ｨｨ09ｨｮｨｪ06ｨｺ 1).

6 THE DISTRIBUTION OF IQ AMONG THE PERSONS OF THE EXPOSED GROUP IN RELATION TO THE THYROID DOSE RANGES IQ ﾁ TABLE Thyroid dose range, Full scale IQ (mean ﾀ SD) N mgy 66ﾓ17 years 106ﾓ112 years 156ﾓ116 years ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ9.7 > ﾀ ﾀ ﾀ9.4 Total ﾀ ﾀ ﾀ10.7 FIGURE 1. DEPENDENCE OF FULL-SCALE IQ FROM INDIVIDUAL THYROID DOSES FROM AT THE AGE OF YEARS AMONG PERSONS OF EXPOSED GROUP (IQ) ﾁ The distribution of average IQ among the persons of the exposed group in relation to the external dose ranges is given in table 5. Subgroup of persons with the highest external antenatal doses (over than 30 mgy) has relatively lower mean full-scale IQ compared to the whole exposed group at the age 6-7 years (85.5 ﾀ6.3 vs ﾀ10.2; p=0.185), at the age years (90.2 ﾀ6.3 vs ﾀ10.4; p=0.199),and at the age years (92.4 ﾀ9.4 vs ﾀ10.7; p=0.057). At the same time,no statistically significant correlation was found in exposed group between individual external antenatal dose and IQ at the age of 6-7 years (r=-0.14),at the age of years (r=-0.13), and at the age of years (r=- 0.19). Figure 2 shows dependence of full-scale IQ from individual external antenatal doses at the age of years among persons of exposed group. 04ｨ ｨｪｨｨ02 IQ 05ｨｨ02 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨ 09ｨｨ09ｨｨｨｬ0609ｨｰｨｨ 06ｨｰ ｨｮ080609ｨｪ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｺｨ 04ｨ ｨｪ06 09 ｨｰｨ ｨ 05ｨｨ ｨｮ0707ｨ ｨｨ ｨｨ02 09 ｨｪｨ ｨｨｨ ｨｺｨｨｨｬｨｨ ｨ ｨｬｨｨ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ07 (ｨ ｨｬ0108) 01ｨ 08ｨ ｨｺｨｰ0208ｨｨ040609ｨ 05ｨ 09ｨｹ ｨ ｨｪｨｨ04ｨｺｨｨｨｬ IQ ｨ 09ｨｪ02ｨｪｨｨｨｨ 09 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ070706ｨｦ ｨｬ ｨ 09ｨｰ ｨｰ (85,5 ﾀ6,3 ｨｨ 89,6 ﾀ10, ｨｰ0902ｨｰ09ｨｰ0902ｨｪｨｪ06; 08=0,185), ｨ 09ｨｰ ｨｰ (90,2 ﾀ6,3 ｨｨ 94,3 ﾀ10,4; 08=0,199) ｨｨ ｨ 09ｨｰ ｨｰ (92,4 ﾀ9,4 ｨｨ 98,2 ﾀ10,7; 08=0,057). 00 ｨｰ ｨｬ07, 09ｨｰｨ ｨｰｨｨ09ｨｰｨｨ ﾂ0209ｨｺｨｨ 04ｨｪｨ ﾂｨｨｨｬ06ｨｦ ｨｺ ｨｨｨｨ ｨｬ020301ｨｮ ｨ ｨｬｨｨ 09ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ07 ｨｰ0205ｨ ｨ ｨｨ 0706ｨｺｨ 04ｨ ｨｰ020507ｨｬｨｨ ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ ｨ 09ｨｰ (r = -0,14), (r = -0,13),ｨｨ ｨｰ (r = -0,20) ｨｪ06 ｨｪ02 ｨ ｨｨ09ｨｮｨｪ06ｨｺ ｨｺｨ ｨ 02ｨｰ 04ｨ 09ｨｨ09ｨｨｨｬ0609ｨｰｨｹ 06ｨ ｨｴ IQ ｨ 09ｨｰ ｨｰ 06ｨｰ ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪ06ｨｦ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ ｨｨ02 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ

7 TABLE 5 THE DISTRIBUTION OF IQ AMONG THE PERSONS OF THE EXPOSED GROUP IN RELATION TO THE EXTERNAL ANTENATAL DOSE RANGES IQ ﾁ External dose range, Full scale IQ (mean ﾀ SD) N mgy 66ﾓ17 years 106ﾓ112 years 156ﾓ116 years < ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ ﾓ ﾀ ﾀ ﾀ9.9 > ﾀ ﾀ ﾀ9.6 Total ﾀ ﾀ ﾀ10.7 FIGURE 2. DEPENDENCE OF FULL-SCALE IQ FROM INDIVIDUAL EXTERNAL ANTENATAL DOSES AT THE AGE OF YEARS AMONG PERSONS OF EXPOSED GROUP (IQ) ﾁ Family study In the exposed group we found a positive moderate correlation between the IQ of persons and the educational level of their parents - mothers (r=0.50; p<0.01) and fathers (r=0.52; p<0.01). A weaker correlation was found between the intellectual level of persons of the control group and the educational level of their parents - mothers (r=0.41; p<0.05) and fathers (r=0.42; p<0.05). CONCLUSIONS 1. The positive dynamics of intellectual development in persons of exposed group has been observed at the age from 6-7 till No statistically significant correlation was found in exposed group between individual thyroid dose as well as individual antenatal external dose and IQ at the age of 6-7 years, years, and years. 3. Disorders of intellectual development in the exposed group of children were caused mainly by unfavorable social-psychological and social-cultural factors such as a low educational level of parents, break of microsocial contacts and difficulties of adaptation,which appeared in the wake of the evacuation and relocation from the contaminated areas ｨ ｨｪｨｨ ｨｬ02ｨｦｨｪ ｨｺ08ｨｮ0302ｨｪｨｨ ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨｨ05ｨｨ ｨｨｨｰ0205ｨｹｨｪｨｮ06 ｨｺ ｨｨ06ｨｪｨｪｨｮ ｨ ｨｨｨｬ ｨｹ IQ 0102ｨｰ02ｨｦ 0609ｨｪ0609ｨｪ06ｨｦ 0008ｨｮ ｨｨ 06ｨ 08ｨ ｨ ｨｰ0205ｨｹｨｪ ｨｮ080609ｨｪ07 ｨｨ ｨｨｨｰ020502ｨｦ - ｨｬｨ ｨｰ020802ｨｦ (r = 0,50; p<0,01 ) ｨｨ 06ｨｰ (r= 0,52; p<0,01) ｨｪｨｨ04ｨｺｨ 07 ｨｺ ｨｨ07 ｨ 0405ｨ ｨｪｨ ｨｬ020301ｨｮ ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ04ｨｬ ｨｮ080609ｨｪ02ｨｬ 05ｨｨ02 ｨｺ06ｨｪｨｰ080605ｨｹｨｪ06ｨｦ 0008ｨｮ ｨｨ 06ｨ 08ｨ ｨ ｨｰ0205ｨｹｨｪ04ｨｬ ｨｮ080609ｨｪ02ｨｬ ｨｨ ｨｨｨｰ020502ｨｦ ( ｨｬｨ ｨｰ020802ｨｦ r = 0,41; p<0,01; ｨｰ r = 0,42; p<0,01) ｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ02 05ｨｨ02 06ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨ 09ｨｰ02 06ｨｰ ｨｰ 01ｨ 08ｨ ｨｺｨｰ0208ｨｨ040609ｨ ｨｹ ｨｨｨｰ0205ｨｹｨｪ06ｨｦ 01ｨｨｨｪｨ ｨｬｨｨｨｺ06ｨｦ ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨｪ ｨｪ06 ｨｺ ｨｨ06ｨｪｨｪ06ｨｦ 04ｨ 09ｨｨ09ｨｨｨｬ0609ｨｰｨｨ ｨｨｨｪ01ｨｨ09ｨｨ01ｨｮｨ 05ｨｹｨｪ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨ 05ｨｮ- ﾂ02ｨｪｨｨ ｨｨ ｨ ｨｪｨｰ02ｨｪｨ ｨｰｨ 05ｨｹｨｪ ｨｪ0203ｨｪ ｨ 05ｨｮ ﾂ02ｨｪｨｨ07 ｨｨ IQ ｨ 09ｨｰ ｨｰ, ｨｰ ｨｨ ｨｰ ｨｪ0609ｨｪｨｮ ｨｹ ｨｨ ｨｪｨｨｨｨ ｨｪｨ 08ｨｮ0302ｨｪｨｨｨｦ ｨｨｨｪｨｰ ｨｺｨｰｨｮｨ 05ｨｹｨｪ ｨ 0409ｨｨｨｰｨｨ ｨ 05ｨｮ ﾂ02ｨｪｨｪ06ｨｦ 0008ｨｮ ｨｰ02ｨｦ ｨｨ0008ｨ 05ｨｨ ｨｪ02ｨ 05ｨ ｨｨ07ｨｰｨｪ ｨｨ ｨｨ ﾂ0209ｨｺｨｨ02 ｨｨ ｨｨｨ 05ｨｹｨｪ ｨｬ060008ｨ 00ｨｨ ﾂ0209ｨｺｨｨ02 00ｨ ｨｺｨｰ060804, ｨｰｨ ｨｺｨｨ02 ｨｺｨ ｨｺ ｨｪｨｨ04ｨｺｨｨｨｦ 06ｨ 08ｨ ｨ ｨｰ0205ｨｹｨｪ04ｨｦ ｨｮ ｨｪｨｹ ｨｨｨｰ020502ｨｦ, ｨｨ02ｨｨｨｰ ｨｨｨｪ000608ｨｬｨ 02ｨｨｨｨ, 08ｨ ｨｬｨｨｨｺ ｨｨｨ 05ｨｹｨｪ0401 ｨｺ06ｨｪｨｰｨ ｨｺｨｰ0609 ｨｨ ｨｰ08ｨｮ01ｨｪ0609ｨｰｨｨ ｨ 01ｨ 07ｨｰｨ 02ｨｨｨｨ, ｨｪｨｨｨｺ03ｨｨ ｨｪｨｨ07 ｨｨ ｨｰ08ｨ 01ｨ 0903ｨｨ01 08ｨ ｨｦ06ｨｪ

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