Perfluoroalkyl chemicals and mortality: an exploratory analysis using NHANES 1999-2014

Abstract

Background: Per- and Polyfluoroalkyl Substances (PFAS) are ubiquitous synthetic chemicals that have been widely used in industrial and consumer products, and are detected in the blood of more than 98% of Americans. PFAS have been linked to increased risks of multiple health outcomes such as cardiovascular disease (CVD) and cancer. Aim: To examine the associations of PFAS exposures with all-cause, CVD, and cancer mortality in the general US population using the most up-to-date publicly available data. Methods: The current study included participant-level data for 5,839 adults aged 45 years or older from the National Health and Nutrition Examination Survey (NHANES) 1999-2000 and 2003-2014 that were eligible for linkage to the public-use National Death Index (NDI) Mortality Files. The associations between 5 individual PFAS, including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and perfluorodecanoic acid (PFDA) and mortality were examined using survey-weighted Cox-Proportional Hazards model with the age as the time scale. Hazard ratios (HR) were calculated to compare the mortality HR of participants per interquartile range (IQR) increase in log-transformed serum PFAS concentrations. Results: After adjusting for sex, race, education, BMI, hypertension, cholesterol level, and survey cycle, most PFAS were not statistically significantly associated with increased risk of CVD or cancer mortality. While higher PFOS and all PFAS were inversely associated with CVD and all-cause mortality risks, respectively (p < 0.05), the observed associations became null when analyses were restricted to participants without chronic kidney disease (CKD). Conclusions: Based on the most available data from NHANES, there was no evidence of increased risks of CVD or cancer mortality due to elevated PFAS concentrations. Further studies are needed to fully understand the inverse associations observed in this study as well as the role of CKD in PFAS related health effects. Keywords: Perfluoroalkyls, mortality, NHANES