Breast Cancer Risk and Serum Levels of Per- and Poly-Fluoroalkyl Substances (PFASs): A Case-Control Study Nested in the California Teachers Study

摘要

Background: Per- and poly- fluoroalkyl substances (PFASs) are a large family of synthetic chemicals, some of which are known mammary gland toxicants and endocrine disruptors. Their potential as human breast carcinogens is unclear. Objective: Our objective was to evaluate the risk of breast cancer associated with serum levels of several PFASs in a nested case-control study within the California Teachers Study (CTS). Methods: Participants were 902 women with invasive breast cancer (cases) and 858 with no such diagnosis (controls) who provided 10 mL of blood and were interviewed about specific exposures between October 2011 and August 2015. Serum PFASs were measured using automated online SPE-HPLC-MS/MS methods. Statistical analyses were conducted for six PFASs with detection frequencies > 95%: PFOA (Perfluorooctanoic acid), PFNA (Perfluorononanoic acid), PFUnDA (Perfluoroundecanoic acid), PFHxS (Perfluorohexane sulfonic acid), PFOS (Perfluorooctane sulfonic acid), MeFOSAA (2-(N-Methyl-perfluorooctane sulfonamido) acetic acid. Unconditional logistic regression models were used to calculate the adjusted odds ratio (OR), estimating breast cancer risk associated with each PFAS. Results: With few exceptions, ORs did not statistically differ from one. ORs were less than one and statistically significant for PFOA (p=0.043) and PFUnDA (p=0.044) and of borderline statistical significance for PFHxS (p=0.060), with little evidence for trend. Conclusion: Overall these findings do not provide evidence that serum PFAS levels measured after diagnosis are related to breast cancer risk in this population of middle-aged or older California women. The few inverse associations found may be due to chance or may be artifacts of study design. Future studies should incorporate information about genetic susceptibility, endogenous estrogen levels, and measurements of PFASs prior to diagnosis.