Triazine herbicide exposure and breast cancer incidence: an ecologic study in Kentucky counties.
Kettles-MA; Browning-SR; Prince-TS; Horstman-SW
Environ Health Perspect 1997 Nov; 105(11):1222-1227
An ecological analysis of a possible link between triazine herbicide exposure and female breast cancer in Kentucky counties was performed. A total of 735 groundwater samples collected from wells in 79 of the 120 counties in Kentucky were analyzed for triazines. A total of 3,254 surface water samples from 113 counties were also analyzed for triazines. Data on corn production for the years 1970, 1980, and 1990 obtained from the Kentucky Agricultural Statistics database and information on the amounts of herbicides used in all counties in 1979 obtained from the Kentucky College of Agriculture were used as surrogate measures of atrazine (1912249) exposure. The water analysis and surrogate data were combined into a summary index that classified each county as having low, medium, or high levels of atrazine exposure. Data on female breast cancer incidence rates for each county for the period 1991 through 1994 were obtained from the Kentucky Cancer Registry. Associations between the indices of triazine exposure and breast cancer were examined for the two year periods 1991 and 1992 (1991/1992) and 1993 and 1994 (1993/1994) by Poisson regression analysis after controlling for age, race, age at first live birth, income, and educational background. Medium and high levels of triazine exposure were significantly associated with an increased risk for breast cancer, odds ratios 1.09 and 1.07 for 1991/1992 and 1.14 and 1.20 for 1993/1994, respectively. The authors conclude that the results of this analysis suggest that a relationship between triazine exposure and female breast cancer exists. Conclusions regarding causality, however, cannot be drawn because of the ecologic design of this study and the inherent limitations in ecologic studies.
Breast-cancer; Women; Herbicides; Occupational-exposure; Environmental-exposure; Water-analysis; Epidemiology; Risk-analysis; Agricultural-industry; Information-systems; Statistical-analysis;
Author Keywords: breast cancer; ecologic study; organochlorines; pesticides; triazine herbicides; xenoestrogens
M.A. Kettles, Department of Preventive Medicine and Environmental Health, University of Kentucky College of Medicine, 1141 Red Mile Road, Lexington, KY 40504-9842 USA
Environmental Health Perspectives