Phthalate exposure and prostate cancer in a population-based nested case-control study

Background: Phthalic acid esters are established as endocrine disruptors. The study aimed to evaluate the association between urinary phthalate metabolites and prostate cancer occurrence. Methods: The study was based on the Taiwan Community-Based Cancer Screening Program, which was set up in 1991-1992 and followed periodically. By 2010, 80 incident prostate cancer cases were identified in the 12,020 men. For each case, 2 controls were randomly selected, matched by age (+/- 3 years), urine collection date (+/- 3 months), and residential township. Frequently used phthalate metabolites from the urine samples were quantified by liquid chromatography/electrospray ionization tandem mass spectrometry. Logistic regression was conducted to assess the association between the exposure levels and prostate cancer occurrence. Results: Exposure to di (2-ethylhexyl), butyl-benzyl and di-isobutyl phthalates (DEHP, BBzP, DiBP) was positively associated with prostate cancer in men with waist circumference (WC) >= 90 cm but not in the leans. Odds ratio for the DEHP metabolite summary score (upper tertile compared to the rest) and prostate cancer were 7.76 (95% CI = 1.95-30.9) for WC >= 90 cm. Conclusions: DEHP, BBzP, and DiBP exposure were associated with prostate cancer occurrence in abdominally obese men. The main limitation remains the lack of mechanistic experiments and comparable toxicological data.