The importance of time of exposure to harmful anthropogenic factors as an element of cancer risk assessment in children

This study attempted to verify whether the time of exposure to harmful factors is important for the increased risk of developing cancer. A statistical analysis of all cases of cancer in children in the period from 1995 to 2004 in the province of Silesia (Poland) was conducted, and their spatial distribution was then presented using cartographic and GIS methods. The data were then juxtaposed with the developed assessment of the degree of anthropogenic pressure in the province of Silesia with regard to: population density, the volume of produced waste and the density of road networks. The anthropogenization index, which was determined by taking into account the selected factors and the degree of impact on human health, was presented as values from 0 to 1, where 0 represents no anthropogenic pressure and 1 represents its maximum level. In the province of Silesia, the estimated values of the anthropogenization index range from 0.2 to 0.67. The study revealed significant variation in the incidence rates in certain age groups, sexes and districts. It also showed a change in incidence rate values in 2004 compared to 1995, with the largest increase (over 9-fold) occurring in boys. In girls, a decrease (almost 5-fold) in incidence rates was recorded in most cancer groups. The correlation coefficient which was determined indicates a diverse relationship between exposure time and the number of cases of cancer, but in only a few districts it is statistically significant.