MEXICO—Exposure to some phthalates may increase the risk of developing breast cancer, according to a study of Mexican women (Environ Health Perspect :-. doi:10.1289/ehp.0901091). However, the study found other phthalate were inversely associated with breast cancer rates.
Researchers examined 233 patients with breast cancer and 221 similarly aged women without cancer. They found phthalate metabolites in urine samples of at least 82 percent of women. The geometric mean concentrations of monoethyl phthalate (MEP) were higher women who had breast cancer than in controls (169.58 vs. 106.78 µg/g creatinine). After adjusting for risk factors and other phthalates, MEP urinary concentrations were positively associated with breast cancer (OR highest vs. lowest tertile: 2.20; 95 percent CI: 1.33–3.63; p for trend<0.01). This association became stronger when estimated for premenopausal women (OR T3 vs. T1: 4.13; 95 percent CI: 1.60–10.70; p for trend<0.01).
In contrast, controls showed significantly higher concentrations of mono-n-butyl phthalate (MBP), mono(2-ethyl-5-oxohexyl) phthalate and mono(3-carboxypropyl) phthalate (MCPP) than the women with breast cancer. Significant negative associations were observed for monobenzyl phthalate (MBzP) and MCPP and cancer risk.