Identifying breast cancer high risk areas in Georgia in relation to environmental chemical exposures

Geographic variations in breast cancer incidence have been found to occur nationally and internationally with a high incidence rate in more industrialized regions. Exposure to higher levels of hazardous chemical substances in the environment could be an important etiologic factor. In this study, we identified breast cancer high risk counties in Georgia and assessed possible environmental chemical exposures in those areas by analyzing ecological data. A total of eight counties (five in the metropolitan Atlanta area) with a statistically significant high incidence rate of breast cancer were identified by comparing their annual age-adjusted incidence rate of female breast cancer for the years of 2001-2005 with the state average rate. By analyzing air pollutant emission data from the U.S. Environmental Protection Agency, we found that these counties had a much higher average emission density from both point and nonpoint sources than that in the identified four low-risk counties. The number and type of industrial facilities in the high-risk counties were also shown to be different from that in the low-risk counties. A pulp mill industry was found in the county with the highest incidence rate of breast cancer. The high and low risk counties associated with environmental variables were mapped using a Geographic Information System. This study suggests that environmental chemical exposure might contribute to the increased rate of breast cancer in industrialized regions. Pollution control measures should be set in place to reduce long-term exposure to toxic chemicals in the high-risk areas for breast cancer prevention.