Sociodemographic and Perinatal Predictors of Early Pregnancy Per- and Polyfluoroalkyl Substance (PFAS) Concentrations

Abstract

Per- and polyfluoroalkyl substances (PFASs), used in food packaging and stain-resistant coatings, are suspected developmental toxicants that are ubiquitous and persistent in the environment. We measured plasma PFAS concentrations during early pregnancy (median = 9.7 weeks gestation) among 1645 women in the Boston-area Project Viva cohort, recruited during 1999–2002. We used multivariable linear regression to estimate associations of sociodemographic and perinatal predictors, including measures of pregnancy physiology (albumin, glomerular filtration rate (GFR)), with log-transformed plasma PFAS concentrations. Geometric mean concentrations for the four main PFASs, perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexanesulfonate (PFHxS) and perfluorononanoate (PFNA) were 25.4, 5.7, 2.5, and 0.6 ng/mL, respectively, comparable with general U.S. population concentrations during those years. Higher early pregnancy PFAS concentrations were associated with younger age (except PFNA), less educational attainment, nulliparity, no history of breastfeeding and higher prepregnancy body mass index in adjusted models. In addition, lower GFR was associated with 3–4% higher PFAS concentrations and higher albumin was associated with 4–6% higher PFAS concentrations. Our results show associations consistent (parity and breastfeeding) and less consistent (age and education) with previous studies. We also report associations with GFR and albumin, which were strongly related to PFAS concentrations and thus could confound estimates of PFAS–outcome associations in epidemiologic studies.

Factors Associated with Maternal Serum Levels of Perfluoroalkyl Substances and Organochlorines: A Descriptive Study of Parous Women in Norway and Sweden

“…The weak negative association we observed between pre-pregnancy BMI and PFOS is in contrast to other studies that reported positive [7, 38, 45] or null associations [42, 48]. This finding, together with the negative association between maternal height and PFAS levels, is not completely understood, but may be due to proposed poorer plasma volume expansion, leading to higher PFAS levels, among smaller sized women [49].…”

“…Only one other study has examined associations between GFR and PFASs among pregnant women [45], and like that study, we found an inverse association between GFR and PFOS (p = 0.002) in a sub-sample (n = 88). GFR describes the flow rate of filtered fluid through the kidney, and we postulate that higher GFR leads to more excretion of PFASs and thereby lower serum levels of PFASs.…”

Prenatal Exposure to Perfluoroalkyl Substances and Body Fatness in Girls

“…In the early 1990's when the ALSPAC prenatal blood collection took place, one important source of PFC exposure is thought to have occurred through contact with new furnishings and carpets in home and office settings; thus, participants of higher socioeconomic status might have experienced the highest exposures. Interestingly, concentrations of maternal PFCs in this data tend be positively associated with educational status (23)(24)(25). In this data, daughters of less educated (lower socioeconomic status) moms may have experienced more complex dynamic combinations of environmental, lifestyle and social stressors over time (20).…”

Shorter duration of breastfeeding at elevated exposures to perfluoroalkyl substances

“…Maternal smoking [6, 7, 9], maternal alcohol intake [10], high maternal BMI [7, 9], low maternal age [6-9], low maternal education [6-9], maternal employment [6], and primiparity [6, 8] have all been associated with reduced duration of breastfeeding. These factors might also be associated with PFAS exposure [25-29], although only the association between higher parity and reduced serum-PFAS concentrations is consistent across studies [25-27, 29]. Confounding was identified as backdoor paths between maternal serum-PFAS concentrations and breastfeeding [30], and these paths were blocked by conditioning on one of the variables on each path if information was available [31].…”

“…Since knowledge about sources of PFAS exposure is limited and results from existing studies of predictors are inconsistent [25-29], we also tested associations between potential confounding variables and the log-transformed serum-PFAS concentrations in linear regression models adjusted for cohort, and the estimates of association were converted to express the percent differences in serum-PFAS concentrations with a one-unit increase in the covariate.…”