Relation between the thyroid diseases prevalence and doses of radiation exposure in the individuals relocated from radioactively contaminated areas in South Urals

Abstract

The objective of this work was to reveal the relations between thyroid pathology prevalence and absorbed thyroid radiation dose from 131I in the individuals relocated into Ozyorsk from the radioactively contaminated areas of South Urals. The sources of data for statistical analysis were the electronic database “Thyroid” containing clinical and laboratory data, and electronic database “The man and the environment” containing dosimetry information on irradiated individuals. Thyroid diseases and individual thyroid doses from all sources of ionizing radiation were collate for 195 persons relocated into Ozyorsk from the villages of the Techa riverside and of the territory of the East Ural Radioactive Trace. Statistical analysis of the data was performed using a software package (Excel, Statistica 6.1). The prevalence of thyroid nodules increased in relocated female statistically significantly 1.7 times (p=0.03) in the range of thyroid doses of 1000-1499 mGy and 2 times (p=0.003) in the range of doses of 1500–1999 mGy compared to this parameter at the doses below 1000 mGy. The prevalence of all thyroid abnormalities has been increased 1.5 times (p=0.007) in the range of thyroid doses of 1500-1999 mGy. An increased prevalence of thyroid diseases by 1.6 times (p=0.02) relative to non-irradiated persons was noted for relocated female whose age at the time of the medical examination was less than 60 years only. A significant number of risk factors requires the use the multivariate statistical analysis to assess their contribution for the development of thyroid pathology in the individuals residing in childhood in radioactively contaminated areas.