Spatial geochemical differentiation of the iodine-induced health risk and distribution of thyroid cancer among urban and rural population of the Central Russian plain affected by the Chernobyl NPP accident.

The main goal was to study the spatial distribution of thyroid cancer (THYC) among the population of urban and rural settlements of four regions of Russia, which were characterized by different contents of stable iodine in soils and exposed to radioactive fallout of I from the Chernobyl NPP. Using GIS technologies, zoning of territories for the deficiency of I and pollution with I was performed. The resulting risk maps were compared with the THYC distribution. The association between the spatial distribution of the total (natural and man-made) risk assessment and the incidence of THYC at the district level tended to have a higher positive correlation (r = 0.505, p < 0.001, n = 94) compared with the correlation of the latter parameter with a fallout density of I (r = 0.468, p < 0.001). After latent period, the incidence of THYC among residents of urban settlements of the Bryansk region was considerably higher than in rural, the difference increasing with time. The correlation between the assessed total risk and THYC distribution in risk zones was significant and higher in the rural areas than in the urban ones. A tendency for a negative significant correlation (r = - 0.55, p = 0.01) between daily iodine intake (based on the main components of the diet) and THYC cases among the rural population was found. A definite difference in the influence of geochemical environmental factors on the distribution of THYC among urban and rural populations deserves more detailed study to prevent this disease.