2 research outputs found
Residential Proximity to Agricultural Pesticide Use and Incidence of Breast Cancer in California, 1988–1997
California is the largest agricultural state in the United States and home to some of the world’s highest breast cancer rates. The objective of our study was to evaluate whether California breast cancer rates were elevated in areas with recent high agricultural pesticide use. We identified population-based invasive breast cancer cases from the California Cancer Registry for 1988–1997. We used California’s pesticide use reporting data to select pesticides for analysis based on use volume, carcinogenic potential, and exposure potential. Using 1990 and 2000 U.S. Census data, we derived age- and race-specific population counts for the time period of interest. We used a geographic information system to aggregate cases, population counts, and pesticide use data for all block groups in the state. To evaluate whether breast cancer rates were related to recent agricultural pesticide use, we computed rate ratios and 95% confidence intervals using Poisson regression models, adjusting for age, race/ethnicity, and neighborhood socioeconomic status and urbanization. This ecologic (aggregative) analysis included 176,302 invasive breast cancer cases and 70,968,598 person-years of observation. The rate ratios did not significantly differ from 1 for any of the selected pesticide categories or individual agents. The results from this study provide no evidence that California women living in areas of recent, high agricultural pesticide use experience higher rates of breast cancer
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Residential proximity to agricultural pesticide use and incidence of breast cancer in the California Teachers Study cohort.
We examined the association between residential proximity to agricultural pesticide use and breast cancer incidence among members of the California Teachers Study cohort, a large study of professional school employees with extensive information on breast cancer risk factors, followed for cancer incidence since 1995. We identified 1552 invasive breast cancer cases, diagnosed between 1996 and 1999, among 114,835 cohort members. We used California Pesticide Use Reporting data to select pesticides for analysis based on use volume, carcinogenic potential, and exposure potential; a Geographic Information System was used to estimate pesticide applications within a half-mile radius of subjects' residences. We applied Cox proportional hazard models to estimate hazard rate ratios (HR) for selected pesticides, adjusting for age, race, and socioeconomic status. We saw no association between residential proximity to recent agricultural pesticide use and invasive breast cancer incidence. HR estimates for the highest compared to the lowest exposure categories for groups of agents were as follows: probable or likely carcinogens (1.07, 95% confidence interval (CI): 0.86-1.32), possible or suggestive carcinogens (1.06, 95% CI: 0.87-1.29), mammary carcinogens (1.15, 95% CI: 0.90-1.48), and endocrine disruptors (1.03, 95% CI: 0.86-1.25). HR estimates for other groups and individual pesticides did not differ from unity, nor was there a trend for any groupings of or individual pesticides examined. Stratifying by menopausal status or family history of breast cancer did not substantially affect our results. Our analyses suggest that breast cancer incidence is not elevated in areas of recent, high agricultural pesticide use in California