Perfluoroalkyl substances and metabolic syndrome.

BACKGROUND: Perfluoroalkyl substances (PFAS) are a class of contaminants used in many industrial applications and consumer products. Certain PFAS are regulated or voluntarily limited due to concern about environmental persistence and adverse health effects.

OBJECTIVES: In this analysis we examine PFAS levels and their association with metabolic syndrome and its components, using a representative sample of the U.S.

POPULATION: Data on PFAS levels and metabolic syndrome components were collected from the 2007-2008, 2009-2010, 2011-2012, and 2013-2014 cycles of the National Health and Nutrition Examination Survey. Twelve different PFAS were measured in serum samples from participants. Logistic regression models were used to identify associations between metabolic syndrome, its individual components, and serum PFAS concentrations.

RESULTS: Over one-third (37%) of participants met the definition for metabolic syndrome, with increased waist circumference and elevated glucose being the most commonly reported components. Seven PFAS were detected in at least 30% of participants and were examined in subsequent analyses (PFDA, PFOA, PFOS, PFHxS, MPAH, PFNA, PFUnDA). The PFAS with the highest concentrations was PFOS (median 8.4 ng/mL), followed by PFOA, PFHxS and PFNA. After adjusting for potential confounders, PFNA was associated with increased risk of metabolic syndrome and well as several individual components, while the highest levels of PFHxS were associated with elevated triglycerides. Other PFAS were associated with decreased risk of at least one outcome.

CONCLUSIONS: Associations between PFAS and metabolic syndrome are inconsistent within and across studies. PFNA was consistently associated with increased risk for components of the syndrome, a finding that warrants further investigation.