Polybrominated Diphenyl Ether Flame Retardants and Thyroid Cancer Risk in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial

Abstract

Polybrominated Diphenyl Ether Flame Retardants and Thyroid Cancer Risk in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening TrialAbstract Number:2651 Mary H. Ward*, Briseis Aschebrook-Kilfoy, Curt DellaValle, Christopher Kim, Mark Purdue, Nathaniel Rothman, Yawei Zhang, and Andreas Sjodin Mary H. Ward* National Cancer Institute, United States, E-mail Address: [email protected] Search for more papers by this author , Briseis Aschebrook-Kilfoy University of Chicago, United States, E-mail Address: [email protected] Search for more papers by this author , Curt DellaValle National Cancer Institute, United States, E-mail Address: [email protected] Search for more papers by this author , Christopher Kim National Cancer Institute, United States, E-mail Address: [email protected] Search for more papers by this author , Mark Purdue National Cancer Institute, United States, E-mail Address: [email protected] Search for more papers by this author , Nathaniel Rothman National Cancer Institute, United States, E-mail Address: [email protected] Search for more papers by this author , Yawei Zhang Yale University, United States, E-mail Address: [email protected] Search for more papers by this author , and Andreas Sjodin Center for Disease Control and Prevention, United States, E-mail Address: [email protected] Search for more papers by this author AbstractBackground: Polybrominated diphenyl ethers (BDEs) disrupt thyroid hormone homeostasis in humans but the relationship with thyroid cancer is unknown. Concentrations of BDEs in human serum increased steadily in the U.S. population through the mid-2000s due to their use as flame retardants in a variety of commercial and household products. Objective: To investigate whether BDE levels in serum are associated with risk of thyroid cancer.Methods: We conducted a nested case-control study of thyroid cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Blood samples were collected between 1992 and 2001 at 10 U.S. centers. Thyroid cancer cases (N=106) were diagnosed through 2009. Controls (N=211) were individually matched (2:1) to cases by race, sex, birth date (<1 year), center, and blood collection date (<15 days). We used gas chromatography isotope dilution high resolution mass spectrometry to analyze 10 tri- to heptabrominated BDEs in serum. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression for lipid-adjusted BDEs detected in >50% of controls (BDE-47, BDE-99, BDE-100, BDE-153) and for the sum of these BDEs (total BDEs) and were adjusted for education, smoking, and body mass index.Results: We observed no significant differences between cases and controls in lipid-adjusted concentrations of total BDEs [median (IQR) cases=13.1 (6.6–42.2); controls=19.4 (7.8–50.2)] or the individual congeners. Increasing quartiles of total BDEs, BDE-47, BDE-99, BDE-100, and BDE-153 were not associated with risk of thyroid cancer (4th vs. 1st quartile total BDEs: adjusted OR=0.65, 95% CI 0.31-1.37; p-trend=0.57).Conclusions: Our study does not support a relationship between BDE exposure and thyroid cancer risk. Future studies of larger populations with repeated measurements and higher exposures will be informative.