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Tuesday, August 28th., 2018

INMA: "Advances in the knowledge of pregnancy exposures"

Non-stick cookware, personal care products or stain repellents for food packaging can contain Perfluoroalkyls (PFAS), a group of manmade substances extensively used in industrial applications. Prenatal exposure to PFAS might affect children’s health. These substances also concentrate in fish and shellfish.

PFAS have a high affinity to serum albumin and their half-lives are of three to seven years. Four PFAS were studied: perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA) and perfluorononanoate (PFNA).

However, maternal determinants of PFAS exposure during pregnancy remain unclear. PFAS concentration in mother’s blood plasma can be influenced by a great variety of socio-demographic and dietary factors, but there is no consensus as to which factor may be more relevant for pregnant women. The contribution of fish or other food to this exposure has not been properly studied either. Besides, the main studies assessing the role of socio-demographic or dietary determinants of PFAS concentration used samples taken before or during 2002, when PFOS were not yet phased out.

As a consequence of this uncertainty, a study of Gipuzkoa, Sabadell and Valencia INMA cohorts from 2003 to 2008 analyzed prenatal concentrations of PFAS in 1216 mothers from these cohorts and their association with different socio-demographic and dietary factors. Plasma samples were collected during the 1st trimester. This study is one of the largest made in the Mediterranean region, and the largest analyzing dietary sources of PFAS concentration during pregnancy.

PFOS showed the highest concentrations of all the detected PFAS. Maternal country of birth and region of residence seemed to have the biggest influence on PFAS concentration, being lower in women born outside Spain than in Spain, and lower in those living in Gipuzkoa than in those living in Sabadell and Valencia (especially for PFHxS). They were also lower in younger women (for PFHxS and PFOS) and in those with more children (for PFOA and PFNA). Another factor associated with a lower concentration was having breastfed for more than 6 months compared to those who had never breastfed (for PFHxS and PFOA). With respect to diet, fish and shellfish intake was the main factor associated with higher concentration of these substances, especially for PFOS. A higher PFAS concentration with higher red meat intake was also found, but not with tap water consumption, something that was found in other studies.

Some of the PFAS (PFOS and PFOA) were detected in almost every woman, suggesting that during the years 2003-2008 exposure was ubiquitous. However, their concentrations were 4 times lower than those observed in previous cohorts in the United States (collected during the years 1999-2002), when PFAS were largely produced.

REFERENCE: Manzano-Salgado CB, Casas M, Lopez-Espinosa MJ, Ballester F, Martinez D, Ibarluzea J, Santa-Marina L, Schettgen T, Vioque J, Sunyer J, Vrijheid M. Variability of perfluoroalkyl substance concentrations in pregnant women by socio-demographic and dietary factors in a Spanish birth cohort. Environ Int. 2016 Jul-Aug;92-93:357-65.

Link: https://www.ncbi.nlm.nih.gov/pubmed/27132161