Endocrine-disrupting chemicals (EDCs) may mimic or interfere with hormone action in the body. The endocrine system is one of the body’s main communication networks. It produces hormones that direct communication and coordinate functions among tissues throughout the body. The ovaries, testes, adrenal glands, thyroid, pituitary gland, liver, fat tissue, muscle, bone, and pancreas are all part of the endocrine system.
EDCs are found in many everyday products, including some plastic bottles and containers, food-can liners, detergents, toys, cosmetics, and pesticides. There is concern that exposure to these chemicals may increase risk for some cancers, contribute to male and female reproductive system problems, increase the rate of obesity and diabetes, be a factor in learning and memory problems, and play a role in various other diseases and dysfunctions.
Although endocrine disruptors can act on the body throughout the human lifespan, the period of child development, starting as early conception and continuing through adolescence, may be an especially sensitive time. During these windows of susceptibility, endocrine disruptors may interfere with processes that determine how tissues are programmed, which may in turn increase susceptibility to adverse health outcomes later in life.
What NIEHS Is Doing
NIEHS funds grants aimed at characterizing how endocrine disruptors influence human health through studies in humans and animal models, and through cell-based approaches that investigate the biological mechanisms involved in associated health effects. NIEHS-funded researchers are developing screening methods to identify and characterize new endocrine disruptors and are working to identify biological markers of EDC exposure. Many studies evaluating endocrine disruptors are examining early life exposures to these chemicals and their effects. This field overlaps with studies on developmental origins of health and disease, environmental epigenetics, preconception exposures, transgenerational inheritance, and other windows of susceptibility.
NIEHS funds grants that are studying the following chemicals that may act as endocrine disruptors:
- Bisphenol A (BPA): a chemical frequently used in plastics and epoxy resins. NIEHS is funding a variety of grants to investigate the health effects of BPA in human studies and animal model systems.
- Dioxins: byproducts of some manufacturing and incineration processes.
- Organophosphates and organochlorines: compounds used in many insecticides, herbicides, and nerve gases.
- Polychlorinated biphenyls (PCBs): chemicals used in electrical equipment. They persist in the environment even though they were banned over 30 years ago.
- Dichlorodiphenyltrichloroethane (DDT): a pesticide banned in 1972 that is still found in the environment today.
- Phthalates: plasticizers used in plastics and in some fragrances and personal-care products.
- Tributyltin and tin compounds: fungicides.
- PFAS — Per- and Polyfluoroalkyl Substances: chemicals used in water and stain resistant products.
- Polybrominated and other flame retardants: chemicals used in furniture and other consumer products to reduce their flammability.
NIEHS also funds researchers examining the endocrine effects of air pollution, heavy metals, and solvents. Other work involves utilizing statistical models to understand the amount of exposure required for adverse health effects to occur.
The institute is interested in research identifying diseases and dysfunctions that were not previously known to be linked with endocrine disruptors; understanding the active sites, pathways, and mechanisms for these chemicals; understanding when during the lifecourse exposure to EDCs may cause health problems; and developing biomarkers of exposure and health effects. Knowledge gained through these studies may help in the development of strategies that reduce the adverse effects of endocrine disruptors.