Household and occupational exposure to pesticides and risk of breast cancer

Abstract

Background: Pesticides are widely used in households and workplaces to control for undesirable pests. Much of the epidemiologic research on this subject has been focused upon examining the relationship between breast cancer and body burden levels of organochlorine pesticides. However, little data exist regarding the association between the use of household or occupational pesticides and the risk of breast cancer. Aims: To examine the relationship between household and occupational pesticide exposure and the risk of breast cancer in a case-control study in Western Australia. Methods: Between May 2009 and July 2011, incident cases of breast cancer and frequency matched controls selected from the general population were enrolled. Information on household pesticide exposure was collected by questionnaire. For occupational pesticide exposure job-specific modules were used. To evaluate potential recall bias, we stratified the analysis by belief about whether pesticides contribute to breast cancer. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CI). Results: Women’s exposure to pesticides in households and workplaces were not related to increased risk of breast cancer; OR=1.10; CI: 0.86-1.37 and OR=0.77; CI: 0.45-1.32, respectively. There was a low prevalence of occupational exposure to pesticides among women. In the stratified analyses, the odd ratios for breast cancer and household pesticide use was not significantly different between women who reported that they believed that pesticides increased breast risk and those who did not report this. Conclusions:Overall, the results of our study did not find a relationship between exposure to pesticides in the workplace or household and breast cancer. However few women were exposure occupationally and thus the power to investigate this exposure was low. Future studies, utilizing a larger sample size and more specific detail on the time frame of pesticide exposure, are needed to further explore this question.