Systematic map of the epidemiology evidence for health effects of 150 data poor per- and polyfluoroalkyl substances (PFAS)

Abstract

Introduction: Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals with widespread use and persistence in the environment and in humans. They are a public health concern, but much of the research to date has focused on a small subset of PFAS, such as perfluorooctanoic acid (PFOA), with much less information available on the health effects associated with other chemicals in the class. Methods: We created a systematic evidence map of epidemiology studies for 150 PFAS. This included literature search and screening, study evaluation focused on risk of bias and sensitivity of the available studies, and extraction of health effect results. Results: Eighty-seven studies were identified with data on at least one health effect. All the studies evaluated exposure to multiple PFAS. Most PFAS (93%, 140/150) had zero studies identified. Among the remaining ten, six had 2-10 studies, three had 11-20 studies, and one (perfluoroundecanoic acid) had 68 studies. The most frequent health effects reported in these studies were reproductive (20), developmental (17), endocrine (16), metabolic (14), and cardiovascular (14). The majority were cross-sectional (47), followed by cohort (36) and case-control (11). In many cases, a large proportion of participants had exposure below the detection limit to the PFAS of interest, which will reduce statistical power and the ability to detect an effect. Discussion: Gaps in the database will limit the ability to draw conclusions about causal associations between these PFAS and associated health effects, and further study is complicated by the large number of PFAS (several thousand) and relatively low levels of exposure in the general population. Regardless, this is an important area to address due to their persistence and the potential for increasing usage as these PFAS are substituted into chemical processes that previously used high-profile PFAS.