Geographic and demographic variability in serum PFAS concentrations for pregnant U.S. women
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The National Children’s Study (NCS) Vanguard Study pilot tested recruitment methods and protocols designed for the National Children’s Study (NCS) Main Study. Over 1,000 pregnant women from seven counties throughout the U.S. were recruited during 2009 and 2010. The intent of the NCS Main Study was to assess relationships between environmental and other exposures and children’s health in the United States in a nationally representative longitudinal birth cohort study. Most women who participated in the Vanguard Study had at least one home visit during pregnancy to collect biomonitoring specimens, environmental samples, and questionnaire data. Here we analyze data obtained from the NCS Vanguard Study Vanguard Data and Sample Archive Access System for PFAS (PFOA, PFOS, PFNA, PFHxS, PFDA) concentrations in the serum of 427 pregnant women from the seven U.S. counties. Geographic variability in PFAS serum concentrations was investigated through summary statistics and tests of difference between sampling locations. Significant differences in serum concentration means were observed among counties for all PFAS species. PFAS serum measurements from pregnant women in the National Health and Nutrition Examination Survey (NHANES) provided a comparison to the general U.S. population and were found to be similar to concentrations observed in the NCS counties. The NCS cohort of pregnant women were then organized into self-reported demographic groups based on income, home age, and drinking water source. Variability in serum concentrations between these groups was used to target spatial mapping analyses in several counties that incorporated publicly available data from the U.S. census, drinking water measurements, and PFAS-related industry locations to hypothesize potential sources of exposure. Findings from one spatial analysis demonstrate that higher serum concentrations in lower income participants in Montgomery County, PA, whereas other counties demonstrate higher serum concentrations in the higher income participants, are in proximity to contaminated drinking water from aqueous film-forming foam (AFFF) use at a nearby military base. This analysis of NCS Vanguard Study data improves understanding of the relative importance of various PFAS exposure sources and associations at the community and household levels. By better identifying vulnerable populations and locations with high potential PFAS exposures, this work contributes to risk management strategies that maximize public health protection.