Determinants of prenatal exposure to perfluoroalkyl substances in the Slovak birth cohort

Background: Perfluoroalkyl substances (PFASs) are man-made fluorinated compounds with endocrine-disrupting properties, detected in 99% of serum samples worldwide and associated with adverse childhood health outcomes. The aim of this study was to describe determinants of prenatal exposure to PFASs in Slovakia. Methods: This study was based on Slovak multicentric prospective mother-child cohort PRENATAL (N = 796). Cord blood samples were collected within 2010-2012 and PFASs were analyzed in a subpopulation of 322 newborns. Concentrations of perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) were measured in the samples of cord blood using an ultrahigh-performance liquid chromatography-mass spectrometry (U-HPLC-MS) method. From questionnaires, we obtained information on medical history of mother, socio-demographic factors, nutrition and environmental factors. Association between maternal characteristics and PFASs exposure was analyzed using multivariable linear regression models. Results: The highest cord blood concentration (geometric mean +/- SD) was observed for PFOA (0.79 +/- 2.21 ng/ml) followed by PFOS (0.36 +/- 2.56 ng/ml), PFNA (0.20 +/- 2.44 ng/ml) and PFHxS (0.07 +/- 2.36 ng/ml). Primiparity was associated with higher levels of all four PFAS: PFOS (exp. beta = 1.25; 95% CI[1.03; 1.53]), PFOA (exp. beta = 1.49; 95% CI[1.18; 1.89]), PFNA (exp. beta = 1.30; 95% CI[1.05; 1.60]) and PFHxS (exp. beta = 1.49; 95% CI [1.20; 1.86]). In addition, maternal age category 29 years and more was associated with higher PFNA and PFHxS levels (exp. beta = 1.27; 95% CI[1.04; 1.55] and exp. beta = 1.30; 95% CI[1.06; 1.60], respectively) and higher educational level of mother was associated with higher PFNA levels (exp. beta = 1.32; 95% CI[1.04; 1.68]). Higher fish consumption was associated with lower PFNA levels (exp. beta = 0.49; 95% CI [0.26; 0.92]). Conclusions: We observed that PFASs cord blood concentrations were comparable or lower than those measured in western or northern European countries. We identified parity as the main determinant of PFASs exposure in our population and maternal age and education as factors that might be associated with exposure to certain PFASs.