Pesticide link to breast cancer uncertain
20 January 2005
A study of farmers’ wives has produced little evidence to support concerns that pesticides used in agriculture can cause breast cancer.
Dr Lawrence Engel, from the National Cancer Institute in Bethesda, Maryland, USA and his team nevertheless say further research needs to be carried out to make sure that there is no risk.
The study, published in the American Journal of Epidemiology, involved 30,454 farmers’ wives living in Iowa and North Carolina in the USA who had no history of breast cancer at the beginning of the research.
Upon joining the study between 1993 and 1997, the women filled out questionnaires regarding pesticide use and other characteristics. By 2000, 309 of the women had been diagnosed with breast cancer.
Analysis showed that overall the incidence of breast cancer was similar for all the women, regardless of whether or not they had been exposed to pesticides.
However, among women who had used the chemical 2,4,5-trichloro-phenoxypropionic acid, as well as other specific pesticides, a small increased risk was observed. Due to only a few women falling into this category, the researchers refrained from drawing firm conclusions
Dr Engel and colleagues summarise that they “found no clear association of breast cancer risk with farm size or washing of clothes worn during pesticide application, but risk was modestly elevated among women whose homes were closest to areas of pesticide application”.
They conclude: “Further follow-up of this cohort should help clarify the relation between pesticide exposure and breast cancer risk.”
