Breast cancer incidence and exposure to environmental chemicals in 82 counties in Mississippi.

OBJECTIVE

Breast cancer is a major public health problem in the United States and in most industrialized countries. Environmental exposure to several chemicals has been implicated in the cause of breast cancer. However, data are not consistent about the role of the environment in breast cancer incidence. To assess environmental risks for breast cancer, patterns of breast cancer incidence in relation to environmental chemicals in Mississippi counties were mapped.

METHODS

This article presents an analysis of age-adjusted incidence rates of female breast cancer and environmental chemical emissions by county in the state of Mississippi. The incidence data were obtained from the State Department of Health, and emissions data sources included the U.S. Environmental Protection Agency's Air-Data and Toxics Release Inventory Program.

RESULTS

Counties having a significantly higher incidence of breast cancer compared with the state's rate were identified. Also identified were counties with higher levels of chemical emissions. The incidence of breast cancer in 1998 was significantly associated with the amount of ammonia (r = 0.268, P = 0.015), minimum emissions (r = 0.233, P = 0.035), and maximum emissions (r = 0.237, P = 0.032) of the facilities in the county. A linear dose-response relationship was observed between increased amounts of chemical emissions and breast cancer incidence.

CONCLUSIONS

This study found a significant link between breast cancer incidence and maximum emissions of environmental chemicals. However, further research using individual-level data is needed.