Serum persistent organic pollutants and prostate cancer risk

Abstract

Background: Until now, most of the human epidemiological studies examining health effects of persistent organic pollutants (POPs) on prostate cancer were conducted as a case-control study design with a small number of participants. Moreover, most of the health risk assessment results were based on animal studies. The present study was a prospective cohort analysis to evaluate the associations between serum concentrations of POPs and prostate cancer risk in Koreans. Using the toxicokinetic model, we estimated cancer hazard risk from exposure to POPs based on human bio-monitoring data. Methods: A case–cohort study was performed based on the Korean Cancer Prevention Study-II. Within the cohort we identified 110 people diagnosed with prostate cancer based on the National Cancer Registry and randomly selected 256 sub-cohort participants without prostate cancer. We measured concentrations of 32 polychlorinated biphenyl (PCB) congeners and 19 organochlorine pesticides (OCPs) in serum samples. The toxic equivalent (TEQ) was calculated based on the individual toxic equivalency factor (TEF) of each PCB congener released from the World Health Organization (WHO) in 2005. Associations between POPs and the risk of prostate cancer incidence were analyzed using the Cox proportional hazard model. We applied toxicokinetic model based on the crude logistic regression model of TEQ and prostate cancer risk to estimate cancer hazard for exposure to POPs. Results: The prostate cancer cases showed elevated serum POPs levels, except for two PCB congeners (PCB52 and PCB101). In a case-cohort study, the increased risk of prostate cancer incidence was observed in the upper tertile of the sum of dioxin-like PCBs (P for trend=0.0395), the sum of non- dioxin-like PCBs (P for trend=0.0019), and TEQ (P for trend=0.0063), compared with the lowest tertile of each POP. Individual POPs (β-HCH, PCB118, PCB167, PCB138, PCB153, and PCB180) showed positive associations with prostate cancer risk. Applying the one-compartment toxicokinetic model, regarding prostate cancer incidence risk we proposed a maximum daily exposure limit of 0.494 pg TEQ/kg bw/day bw/day to dioxin-like PCBs. Conclusion: The findings of this study suggested that the exposure to specific OCPs and PCBs is likely to be associated with the prostate cancer risk in the Korean population.