Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25–29, 2009: Oral Presentations
Background and Objective:
Phthalates are ubiquitous environmental contaminants that disrupt the endocrine system. Phthalates are mainly used as plasticizers in PVC plastics and as additives in personal care products. We assessed the urinary concentrations of nine phthalate metabolites and breast cancer (BC) incidence in an ongoing population based case-control study in northern Mexico.
Histological confirmed BC cases (233) were aged matched with 221 women living in the same area of the index cases. Information about reproductive and dietary history, and potential sources of phthalates was obtained by direct interviews. The following phthalate metabolites were determined by HPLC-MS/MS at the CDC: monoethyl phthalate (MEP), monobenzyl phthalate (MBzP), mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), and mono-3-carboxypropyl phthalate (MCPP).
Detectable concentrations of phthalate metabolites varied from 83% (MEHP) to 100% (MEP, MBP, MEOHP, MEHHP, MECPP). Cases had significantly higher geometric mean concentrations of MEP (169.58 vs. 106.78 mcg/g creatinine) than controls. In contrast, controls presented significantly higher concentrations of MBP, MEOHP and MCPP. After adjusting for known BC risk factors, a significant trend in the increase of BC risk was observed in relation to MEP (OR T3 vs. T1 = 1.75 CI95% 1.07-2.86, P for trend = 0.020) that remained significant and became stronger only in premenopausal women (OR T3 vs,.T1 = 3.06 CI95% 1.27-7.35, P for trend = 0.009). Anti-androgenic phthalates (MBzP, MBP, MiBP) and MCPP were significantly negative associated with BC risk. No significant associations with BC were detected for the rest of phthalates.
MEP is a metabolite of diethyl phthalate, which is mainly used in cosmetics and fragrances. Further estimation of dermal and inhalation exposure to DEP by specific products is warranted. Biological mechanisms of its potential effect on BC should be clearly defined. This first report needs to be replicated.