Polyfluoroalkyl and perfluoroalkyl substances (PFAS) are persistent organic pollutants and exposure have been suggested with the risk of developing preeclampsia. Yet, evidence on the associations of PFAS with preeclampsia is still conflicting. Thus, the current study conducted a systematic review and meta-analysis of the epidemiological evidence linking maternal PFAS exposure to preeclampsia. This research methodology involved searching three electronic databases for epidemiological studies, and then conducting a meta-analysis using a random-effects model to analyse the heterogeneity between the studies. The quality and strength of evidence for each exposure-outcome pair was also evaluated, as well as the risk of bias. The search identified 10 potentially eligible studies related to maternal PFAS blood level with preeclampsia, which 7 were ultimately selected. Meta-analysis demonstrated evidence of association between combined PFAS compounds in pregnant mother with preeclampsia with zero heterogeneity (I2=0.0%, Q= 3.09, df= 6, p=0.798). Preeclampsia was found to have moderate association with maternal perfluorooctanoic acid (PFOA) exposure (Test for overall effect: z=2.2, p=0.03; Test for heterogeneity: I2=0.0%, Q= 3.49, df= 6, p=0.745) as well as maternal perfluorooctane sulfonate (PFOS) exposure (Test for overall effect: z=2.5, p=0.01; Test for heterogeneity: I2=0.0%, Q= 3.70, df= 6, p=0.718). This study showed significant associations between PFOA and PFOS exposure with the risk of preeclampsia. However, in-depth investigation is imperative to elucidate the impact of the different concentration and types of PFAS on preeclampsia risk.
Perfluorinated compounds such as perfluorooctane sulfonate (PFOS) and perfluorooctane acid (PFOA) have been recognized as emerging environmental pollutants because of their ubiquitous occurrence in the environment, biota and humans. The paper focuses on the distribution, bioaccumulation and toxic effects of PFOS and PFOA in the water. From the available literature, tap and surface water samples in several countries were found to be contaminated with PFOS and PFOA. These compounds were detected globally in the tissues of fish, bird and marine mammals. Their concentrations from relatively more industrialized areas were greater than those from the less populated and remote locations. Blood samples of occupationally exposed people and the general population in various countries were found to contain PFOS and PFOA which suggested a possibility of atmospheric transport of these compounds. There is still a death of information about the environmental pathways of PFOS and PFOA. The presence of these compounds in the tap water, surface water and animal and human tissues indicates their global contamination and bioaccumulative phenomena in the ecosystems.
Perfluorooctanesulfonyl fluoride based compounds have been used in a wide variety of consumer products, such as carpets, upholstery, and textiles. These compounds degrade to perfluorooctanesulfonate (PFOS), a persistent metabolite that accumulates in tissues of humans and wildlife. Previous studies have reported the occurrence of PFOS, perfluorohexanesulfonate (PFHxS), perfluorooctanoate (PFOA), and perfluorooctanesulfonamide (PFOSA) in human sera collected from the United States. In this study, concentrations of PFOS, PFHxS, PFOA, and PFOSA were measured in 473 human blood/serum/plasma samples collected from the United States, Colombia, Brazil, Belgium, Italy, Poland, India, Malaysia, and Korea. Among the four perfluorochemicals measured, PFOS was the predominant compound found in blood. Concentrations of PFOS were the highest in the samples collected from the United States and Poland (>30 ng/mL); moderate in Korea, Belgium, Malaysia, Brazil, Italy, and Colombia (3 to 29 ng/mL); and lowest in India (<3 ng/mL). PFOA was the next most abundant perfluorochemical in blood samples, although the frequency of occurrence of this compound was relatively low. No age- or gender-related differences in the concentrations of PFOS and PFOA were found in serum samples. The degree of association between the concentrations of four perfluorochemicals varied, depending on the origin of the samples. These results suggested the existence of sources with varying levels and compositions of perfluorochemicals, and differences in exposure patterns to these chemicals, in various countries. In addition to the four target fluorochemicals measured, qualitative analysis of selected blood samples showed the presence of other perfluorochemicals such as perfluorodecanesulfonate (PFDS), perfluoroheptanoic acid (PFHpA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA), and perfluoroundecanoic acid (PFUnDA) in serum samples, at concentrations approximately 5- to 10-fold lower than the concentration of PFOS. Further studies should focus on identifying sources and pathways of human exposure to perfluorochemicals.