Medical University of South Carolina
Pregnant women often encounter numerous chemicals that may pose a risk to them and their baby. A subset of these chemicals are endocrine disrupting chemicals (EDC), which can affect health outcomes including growth and development, organ function, metabolism, and reproduction. Thousands of manufactured chemicals in use today are EDCs, and exposures to them are often studied individually. However, this approach is limited since mothers often encounter multiple chemicals in combination (a.k.a., mixtures) during the course of their pregnancy.
To further investigate exposure combinations to EDCs, ECHO researcher John Pearce, PhD of the Medical University of South Carolina and his research team developed a new methodology defined as exposure continuum mapping (ECM) that leverages spatially correlated learning for investigating complex exposure patterns (a.k.a. mixtures) in health studies involving numerous exposures. With this study, Dr. Pearce and his team apply ECM to data collected from a diverse mother-child cohort to identify exposure profiles of real world EDC mixtures and to assess how the discovered profiles associated with birth outcomes.
To begin, the team used data previously collected from over 600 women participating in ECHO that also enrolled in the Eunice Kennedy Shriver National Institute of Child Health and Human Development’s (NICHD) Fetal Growth Studies from 2009-2012. These data included concentrations of EDCs measured in blood samples collected from mothers 8-12 weeks into their pregnancy and their infant’s weight at birth. Then, the team analyzed these data with ECM in order to identify the range of EDC exposure profiles experienced by moms during their pregnancy and to examine the relationship to the birth weight of their children.
Findings from the study revealed that moms experienced a broad range of chemical exposure profiles with marked variability in exposure magnitudes across chemical classes and exposure frequencies. Evaluation of health effects found that maternal exposure profiles dominated by higher levels of flame-retardants (i.e., polybrominated diphenyl ethers, PBDEs) were associated to lower birth weights. Exposure profiles with higher levels of polychlorinated biphenyls (PCBs) and perfluoroakyl (PFAS) substances were associated with increased birth weights. PCBs are man-made chemicals that are often found in industrial and commercial products, such as electrical and hydraulic equipment and plasticizers in paints, plastics, and rubber products. PFAS substances can often be found in food packaging, commercial household products, drinking water, and living organisms.
“ECM provides a promising framework for supporting studies of other exposure mixtures as the resulting mapping benefits visualization and assessment of relationships in complex data,” said Pearce. “Moving forward, our team will apply ECM to assist investigations of exposure mixtures and other child health outcomes, with particular interest on obesity.”