Every day we are exposed to hundreds of chemicals in the food we eat, the water we drink, and products we use in our homes. But what makes some chemicals more problematic than others and what does that mean for our health? Our new study sheds light on what PFAS and PBDEs are doing to our bodies and health.
PFAS (per- and polyfluoroalkyl substances) and PBDEs (polybrominated diphenyl ethers) are classes of chemicals found in non-stick cookware, food packaging, water-repellent fabric, and furniture that can stay in our bodies for up to 10 years and sometimes much longer. Exposure to PFAS and PBDEs is associated with an increased risk of preterm birth and preeclampsia among pregnant people and higher levels of PFAS and PBDEs can increase the risk of certain cancers and thyroid disease.
So, while we know that PFAS and PBDEs are toxic, we do not have a good understanding of how these chemicals can make changes in our bodies that lead to health problems. We conducted a study to find out. We hypothesized that the harmful effects of PFAS and PBDEs might occur by changing telomere length. Telomeres are protective caps at the end of our chromosomes that contain genetic information. Telomeres also protect chromosomes from damage. Over time, telomeres naturally get shorter when our cells are replicating. However, things like social stressors and smoking can also alter telomere length. Both extremely short and extremely long telomeres can be harmful. For example, longer telomeres have been associated with certain types of cancers; shorter telomeres are associated with obesity, cardiovascular disease, and premature death.
As part of NIH’s Environmental Children’s Health Outcomes (ECHO) study, we collected blood samples from 110 pregnant women and measured 7 PFAS, 4 PBDEs, and maternal telomere length. At delivery, we collected cord blood from 292 newborns and measured newborn telomere length. We had 76 participants with both maternal and newborn telomere length. We found that these chemicals were detected in nearly all pregnant people enrolled in our study and that many of these chemicals were highly correlated. This tells us that we’re exposed to many of these chemicals at the same time. Because we’re exposed to many chemicals at once, we accounted for this in our statistical analysis by estimating an exposure mixture. We also adjusted for socioeconomic status to isolate the effects of PFAS and PBDEs.
Among pregnant women who had telomere length measured in both mother and child, we found that higher levels of our PFAS and PBDE mixture was associated with longer newborn telomeres. This association was primarily due to PFAS. PFAS and PBDEs were not associated with maternal telomere length, which might be due to other factors (such as social stressors) that also can change telomere length over time.
Our findings reveal that exposure to PFAS and PBDEs during pregnancy is associated with longer telomere length in newborns. This is important because newborn telomere length predicts telomere length in adulthood and longer telomeres are associated with cancer among adults. Our findings highlight a potential pathway linking chemicals to possible cancer risk. Moving forward, it is important for researchers to consider other environmental exposures that may lead to longer telomeres in adults. Policy makers should also consider that exposure to many chemicals occurs simultaneously and consider legislation that regulates chemical classes, as opposed to individual chemicals.
Read more about PFAS here:
About the author
Stephanie Eick, MPH, PhD is a postdoctoral scholar for the Research team. She received her PhD in Epidemiology from the University of Georgia and her MPH in Epidemiology from Emory University. As a postdoc, she works on the NIH’s Environmental Influences on Child Health Outcomes (ECHO) study at UCSF. She is interested in biologic mechanisms that link chemicals and psychosocial stressors to adverse pregnancy and child health outcomes. In September 2021, she will be an Assistant Professor in the Gangarosa Department of Environmental Health at the Emory University Rollins School of Public Health.
Co-authors on this paper are Stephanie M. Eick, Dana E. Goin, Lara Cushing, Erin DeMicco, June-Soo Park, Yunzhu Wang, Sabrina Smith, Amy M. Padula, Tracey J. Woodruff & Rachel Morello-Frosch