Xeno-oestrogenic activity in serum as marker of occupational pesticide exposure.

BACKGROUND An increasing number of currently used pesticides are reported to possess oestrogen-like properties or to disturb the endocrine system in other ways. OBJECTIVES To investigate if xeno-oestrogenic activity in serum can be used as a biomarker of the combined exposure to pesticides with oestrogen-like properties in an occupational setting. METHODS Serum samples were obtained from two separate cohorts representing non-pregnant and pregnant female greenhouse workers in Denmark. Serum samples from 270 non-pregnant women and 173 pregnant women were analysed for xeno-oestrogenic activity. A fraction containing major xeno-oestrogens but without pharmaceutical and endogenously produced oestrogens was isolated from each serum sample by solid-phase extraction and tested for oestrogenic response in a MCF-7 cell proliferation assay. The pesticide exposure for each woman was categorised as low, medium or high based on information collected by detailed interviews of the women and the employers. RESULTS In both cohorts, an exposure-associated increase in the xeno-oestrogenic activity in serum was demonstrated. Among the pregnant women, the association between pesticide exposure and xeno-oestrogenic activity in serum was statistically significant for women who had been at work within the last week, while no association was observed for women who had not been at work during the most recent week. CONCLUSIONS The study illustrates the usefulness of this biomarker for qualitative assessment of the combined exposure to mixtures of oestrogen-like pesticides. Although the individual pesticides responsible for the xeno-oestrogenic response were not identified, the study demonstrates that, even within highly-controlled greenhouse operations, occupational exposure to oestrogen-like pesticides can result in detectable impacts on hormonal activity in the blood.