Serum levels of environmental pollutants is a risk factor for breast cancer in Inuit: a case control study

Maria Wielsøe,Eva Cecilie Bonefeld-Jørgensen,Peder Kern

doi:10.1186/s12940-017-0269-6

Maria Wielsøe, Eva Cecilie Bonefeld-Jørgensen + Show 1 more

Open Access

https://doi.org/10.1186/s12940-017-0269-6

Copy DOI

Abstract

BackgroundEnvironmental Persistent Organic Pollutants (POPs) can alter the hormone homeostasis by mimicking, interfering or blocking the function of hormones; moreover POPs are hypothesized to modify the risk of breast cancer. The association between POPs and breast cancer has been widely studied but the conclusions are inconsistent. The present study examined the associations between serum levels of POPs and breast cancer with focus on the highly exposed Greenlandic Inuit population.MethodsThe study design was a case-control study of Inuit women from Greenland. The participants were asked to complete a questionnaire with information on reproductive history and lifestyle and to provide a blood sample. The sampling was carried out in two time periods (2000–2003 and 2011–2014). The serum levels were determined of 14 polychlorinated biphenyls (PCBs), 11 organochlorine pesticides (OCPs), 16 perfluoroalkyl acids (PFAAs), 1 polybrominated biphenyl (PBB), and 9 polybrominated diphenyl ethers (PBDEs). Independent samples t-test was used to compare differences between cases and controls and odds ratios (OR) adjusted for identified confounders were obtained using logistic regression.ResultsThe study population included 77 breast cancer cases and 84 controls. The majority of the measured compounds declined significantly from 2000 – 2003 to 2011–2014. However, for the perfluorinated carboxylic acids (PFCAs) an increase was observed. The serum levels were significantly higher in cases compared to controls for the majority of the compounds, and after adjusting for age the difference was maintained for ∑OCP, dichlorodiphenyldichloroethylene (p,p′-DDE), ∑PFAA, ∑perfluorinated sulfonic acids (PFSA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS). For the lipophilic POPs, high serum levels (middel/highest vs. lowest tertile) of ∑PCB, ∑estrgoenicPCB, PCB99, PCB138, PCB153, PCB170, PCB170, and PCB183 was associated with breast cancer risk; for the amphiphilic PFAAs, high serum levels of ∑PFAA, ∑PFCA, ∑PFSA, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), PFHxS, and PFOS were associated with breast cancer risk.ConclusionSignificant, positive associations between breast cancer risk and PCBs and PFAAs were observed. The associations indicate that environmental exposure to POPs can be a factor increasing the risk for breast cancer in Inuit women.

Highlights

Environmental Persistent Organic Pollutants (POPs) can alter the hormone homeostasis by mimicking, interfering or blocking the function of hormones; persistent organic pollutant (POP) are hypothesized to modify the risk of breast cancer
Statistics We report data on single compounds detected in more than 50% of the samples and analyses were performed for the summed concentration of the compound groups: 1) ∑Polychlorinated biphenyl (PCB): PCB 99, 101, 105, 118, 128, 138, 153, 156, 170, 180, 183, 187, 2) ∑PCB group 1: PCB 101, 187 3) ∑PCB group 2: PCB 105, 118, 128, 138, 156, 170, 4) ∑PCB group 3 (CYP1A1 and CYP2B inducing PCBs): PCB 99, 153, 180, 183, 5) ∑DL-PCBs: PCB 105, 118, 156, 6) ∑Organochlorine pesticide (OCP): p,p′-DDT, p,p′-DDE, mirex, β-HCH, HCB, cis- and trans-nonachlor, and oxychlordane, 7) ∑Perfluorinated carboxylic acid (PFCA): Perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), Perfluoroundecanoic acid (PFUnA), Perfluorododecanoic acid (PFDoA) and Perfluorotridecanoic acid (PFTrA), 8) ∑perfluorinated sulfonic acids (PFSA): perfluorohexane sulfonate (PFHxS), Perfluorooctanesulfonic acid (PFOS) and PFOSA, and 9) ∑Perfluoroalkyl acid (PFAA): ∑PFCA + ∑PFSA
In a previous case-control study in Greenland we found an association between breast cancer and PFOS (OR:1.03 (1.00; 1.07)) and ∑PFSA (OR:1.03 (1.00; 1.05)) [11] and in additional subsequent analyses we found that PFOSA increased breast cancer risk considerably (OR:6.13 (1.12–33.64)) [10]

Summary

Introduction

Environmental Persistent Organic Pollutants (POPs) can alter the hormone homeostasis by mimicking, interfering or blocking the function of hormones; POPs are hypothesized to modify the risk of breast cancer. Environmental pollutants disturbing the hormone homeostasis by mimicking, interfering or blocking the function of the hormones, have been hypothesized to modify breast cancer risk. Environmental pollutants, such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and perfluorinated alkylated acids (PFAAs), are reported potential endocrine disrupters [3]. Despite indications from in vitro and animal studies, the scientific evidence of associations between endocrine disrupting environmental pollutants and breast cancer risk in humans is inconclusive. Perfluorooctanesulfonic acid (PFOS), perfluorooctanesulfonamide (PFOSA), and ∑perfluorinated sulfonic acids (PFSAs) were reported to increase breast cancer risk in both a prospective and a crosssectional case-control study [10, 11]

Methods

Results

Discussion

Conclusion