You are here:
ARE ENVIRONMENTAL EXPOSURES TO CHLOROPHENOXY HERBICIDES ASSOCIATED WITH AN INCREASE IN ADVERSE HUMAN HEALTH EFFECTS?
Citation:
SCHREINEMACHERS, D. M. ARE ENVIRONMENTAL EXPOSURES TO CHLOROPHENOXY HERBICIDES ASSOCIATED WITH AN INCREASE IN ADVERSE HUMAN HEALTH EFFECTS? Presented at U.S. Geological Survey (USGS) Sixth Biennial Geographical Information Science Workshop, Denver, CO, April 24 - 28, 2006.
Description:
Background: Associations between adverse health effects and environmental exposures are difficult to study because exposures may be widespread, low-dose in nature, and common throughout the study population. Individual risk-factor epidemiology may not be able to initially identify an association. A series of multilevel, multidisciplinary studies, starting with an inter-region comparison for the purpose of hazard identification may be required. Existing databases routinely collected by Federal Agencies can be used for this purpose. Examples are provided in the following studies. Minnesota, Montana, North Dakota, and South Dakota produce most of the spring- and durum wheat grown in the U.S. Chlorophenoxy herbicides have been the predominant herbicides applied to wheat. Because information on herbicide use is not available for individual counties, wheat acreage per county is used as a surrogate exposure measure to study the association between rates of adverse health effects and environmental exposures to chlorophenoxy herbicides and/or contaminants. Previous population studies showed that cancer mortality and birth malformations in rural, agricultural counties of Minnesota, Montana, North Dakota, and South Dakota are associated with wheat acreage per county. This presentation will show associations with ischemic heart disease and diabetes.
Methods: Information on mortality from ischemic heart disease and diabetes during 1979-1988 and 1989-1998 (underlying cause of death) was obtained from the National Center for Health Statistics mortality database. Agricultural information was obtained from the U.S. Department of Agriculture website. Analyses were performed on grouped counties, based on the intensity of their wheat agriculture (low, medium, and high).
Results: Comparison of high- with low-wheat counties with adjustment for age, sex, year of death, and poverty index, showed that mortality from ischemic heart disease and diabetes was increased by 8% and 16%, respectively. Mortality from acute myocardial infarction, the major subgroup of ischemic heart disease, showed an increase of 20%. These results were statistically significant.
Conclusions: Because chlorophenoxy herbicides are among the most widely used herbicides in the U.S., further investigations, including GIS studies, are needed to confirm the observed associations. Dose and route of exposure, distance from cropland, and weather patterns are additional factors that merit attention in future studies.
Disclaimer: This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.