Th137Cs radionuclides, folate cycle and physical development of children living near the Chornobyl exclusion zone

The purpose of the study: to assess the impact of incorporated 137Cs radionuclides on the physical development of boys and girls living near the Chornobyl Exclusion Zone, taking into account the state of the folate cycle and the MTHFR:C677T genetic polymorphism. Research methods: іnstrumental, laboratory, mathematical and statistical. Results: Within the framework of international projects, an assessment of physical development was carried out according to the Rohrer index (IR), the levels and relationship of incorporated 137Cs, vitamins B6, B9, B12, homocysteine (Hcy), allelic variants of the MTHFR:C677T genetic polymorphism were determined in 260 children aged 13-17 years old from Ivankivskyi and Polisskyi districts of the Kyiv region, bordering the Chornobyl Exclusion Zone. It has been established that among the surveyed, the more proportion is the subgroup of adolescents with harmonious physical development (respectively, for boys - 70.40%, for girls - 65.93%). It was shown that boys and girls with disharmonious high physical development (respectively 15.20% and 25.19%) contained significantly less 137Cs radionuclides in their bodies, compared with children from the subgroups of harmonious and disharmonious low physical development. In the analyzed groups of boys and girls, an inverse correlation was recorded between the specific activity of 137Cs and the values of anthropometric indicators. The most pronounced inverse relationship between the specific activity of 137Cs and the values of mass, as well as body length and IR, was found in the subgroup of harmoniously developed girls. The subgroup of harmoniously developed boys differed from the subgroup of harmoniously developed girls by a higher specific activity of 137Cs in the body and a higher level of Hcy in the blood. The decrease in the level of Hcy in the blood of harmoniously developed girls, compared with harmoniously developed boys, may be associated with a higher level of vitamin B12 in the blood, as well as with a more intense functioning of the trans-sulfurization cycle. Comparative analysis showed that in the subgroup of girls with overweight, the proportion of cases of carriage of genotypes composed of neutral alleles of the C/C polymorphism MTHFR:677 is greater than in the subgroup of harmoniously developed girls. At the same time, a lower specific activity of 137Cs in their body was registered. It is concluded that incorporated 137Cs radionuclides cause a decrease in body weight in children living in the area affected by the accident at the Chоrnobyl nuclear power plant. At the same time, there is a metabolic disorder, in the form of an increase in the content of Hcy in the blood, more pronounced in boys. The process of incorporation of 137Cs radionuclides into the body of children may be associated with the T allele of the MTHFR:C677 polymorphism, which affects the activity of methylenetetrahydrofolate reductase.