Influence of Corn Farming on the Immune System
When compared to the general population, farmers have an increased risk of non-Hodgkin's
lymphoma (NHL) and certain other hematopoeitic cancers (i.e., multiple myeloma, leukemia).
Factors that contribute to this excess risk have not been discerned. While several
epidemiologic studies have observed an increased risk of NHL among farmers who are exposed
to certain pesticides (i.e., phenoxyacetic acids, organophosphates, organochlorines, and
triazines), these studies have not been conclusive. In addition, a clear mechanistic
association between farming or pesticide exposure and subsequent development of cancer has
not been identified. Given that immunocompromised individuals are at increased risk for
NHL, it has been hypothesized that altered immune function may be an indicator of increased
potential for the development of immunologically based diseases such as NHL. Therefore,
research into early immunologic effects of farming exposures holds some promise in
discerning disease mechanisms and in identifying specific etiologic agents for lymphatic
cancers such as NHL. Few such studies have been conducted.
This protocol outlines a study of immune effects among corn farmers within Agricultural
Health Study (AHS) cohort. The main objective is to evaluate the changes in immune
parameters in farmers throughout the growing season, as well as effects of specific
pesticide exposures including atrazine and organophosphate (OP) insecticides. Farmers and
control subjects were contacted just prior to planting (February-March) to be enrolled in
the study. Biological sampling before and after planting and application of preemergent
pesticides (likely to include atrazine and possibly Ops or carbamates) allowed examination
of short-term biologic effects associated with specific pesticide exposures and general
planting activities (e.g., tillage). The first post-emergent application of organophosphate
insecticide will also be monitored, in order to evaluate short-term biologic effects
associated with this OP exposture. Post-harvest and off-season samples also were collected
to allow evaluation of overall immune effects of farming activities. Pesticide exposures
(e.g., atrazine, OPs, and potentially 2,4-D or carbamates) are being assessed primarily by
measurement of the parent compound or its metabolites in urine, and additional information
on farming activities and work practices will be obtained by questionnaire. Farmers serve
as their own self-controls, and a selected control group will provide a means for external
comparison.
Observational
N/A
Laura Beane-Freeman
Principal Investigator
National Cancer Institute (NCI)
United States: Federal Government
999902197
NCT00342121
May 2002
Name | Location |
---|---|
National Cancer Institute (NCI), 9000 Rockville Pike | Bethesda, Maryland 20892 |