All ETDs from UAB

School

School of Public Health

Document Type

Dissertation

Department (new version)

Public Health

Date of Award

1999

Degree Name by School

Doctor of Public Health (DrPH) School of Public Health

Abstract

Several pesticides have been reported to contain hormonal properties, especially estrogenic property. Examples of these pesticides are DDT, other organochlorines, and phenoxyherbicides. These pesticides have been reported to be associated with the development of hormone-dependent organ cancers, such as mammary gland and thyroid tumors in animal studies; however, there is no report of an association between specific pesticides and hormone-dependent organ cancers among humans. Farmers who are exposed to pesticides have been found to have a slightly higher risk of cancers. However, the exposure of pesticides are mostly qualitative due to lack of pesticides exposure data among farmers. There is no clear relationship between exposure to pesticides and cancer. In this study, we have looked at the association between the amount of pesticides used and the number of cancers in hormone-dependent organs among farmers. We first determined the association between four major crops that used high amounts of pesticides—corn, cotton, wheat, and soybean—with breast, endometrial, ovarian, prostate, testicular, and thyroid cancers, which are hormone-dependent organ cancers among farmers. Then, we did an assessment of pesticide exposure by using data from the national pesticide surveys conducted by the Economic Research Service (ERS), U.S. Department of Agriculture (USDA) in 1964, 1966, 1971, and 1976 to develop a data set for amounts of common pesticides used by farmers in each state. Finally, we used the pesticides exposure data set to study exposure to some endocrine disrupting pesticides and hormone-dependent organ cancers among farmers. Farmers in 24 states in the United States were categorized, based on the level of pesticides exposure in the states where they lived. We calculated mortality odds ratios for farmers compared with nonfarmers in either high or low pesticide use states. We then calculated the odds ratio for comparison between farmers in high and low pesticide use states. We found that farmers in the high cotton producing states had a significant increase in death from breast and endometrial cancers compared to those in the low cotton producing states. From the pesticides exposure study, we found that high DDT use is associated with breast and endometrial cancers. High toxaphene use is associated with breast, endometrial, and ovarian cancers. Based on these results, it is reasonable to believe that exposure to hormone-like pesticides might be a risk factor of hormone-related organ cancer development among farmers. However, we cannot conclude that these pesticides cause hormone-related organ cancers among farmers from only one study. Further studies need to be done to confirm our findings, both in experimental models and epidemiological studies.

ProQuest Publication Number

Document on ProQuest

ProQuest ID

9949099

ISBN

978-0-599-51322-8

Comments

DrPH

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