Exogenous factors associated with legacy PFAS concentrations in the general U.S. population: NHANES 1999-2018

Abstract

To reduce per- and polyfluoroalkyl substances (PFAS) exposure through legislation and other interventions, we must understand factors contributing to individual body burden. Identifying factors associated with serum perfluorinated compounds (PFAS) concentrations also aids in identifying groups at higher risk of adverse health outcomes due to elevated exposure. This exploratory analysis provides initial findings on exposure-related factors associated with legacy PFAS concentrations in the general United States (U.S.) population. We obtained National Health and Nutrition Examination Survey (NHANES) datasets with individual serum PFAS measurements from cycle years 1999-2018 (N = 14,961), excluding the 2001-2002 cycle due to pooled sampling. Over 100 features were evaluated for associations with PFAS concentrations. Data were singly imputed using hot deck and predictive mean matching (PMM) methods, and model performance by imputation method was compared using elastic net regression (ENR) models. Hot-deck imputation explained the most variance in predictive models; thus, a dataset imputed via hot-deck was used for feature selection. ENR models were employed to identify the top variables associated with legacy PFAS concentrations, and selected features were put into linear mixed models to obtain beta estimates and standard errors. Survey year, demographic, income, place of birth and citizenship status, household size, dietary, health, food insecurity, general health and healthcare, housing, social and behavioral, and other characteristics were important factors associated with legacy PFAS concentrations in this nationally representative study population. A better understanding of exogenous factors associated with PFAS concentrations can influence future epidemiological studies, guiding decisions on adjustment for confounding, and advancing our understanding of factors that affect chemical half-lives and toxicokinetics.