Endocrine-disrupting chemicals (EDCs) may mimic or interfere with hormone actions 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. Exposure to these chemicals may increase risk for cancer, male and female reproductive system problems, obesity, diabetes, learning and memory problems, and various other diseases and dysfunctions.
Although EDCs 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. EDCs 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 biological markers of EDC exposure. Many studies that evaluate endocrine disruptors focus on 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 grantees are studying the following chemicals:
- Bisphenol A (BPA): a chemical frequently used in plastics and epoxy resins. NIEHS is funding a variety of grants to investigate 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 that 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: chemicals used in fungicides to combat mold.
- Per- and Polyfluoroalkyl Substances (PFASs): chemicals used in some firefighting foams and stain-resistance products.
- Polybrominated and other flame retardants: chemicals used in furniture and other consumer products to reduce their flammability.
NIEHS also funds researchers who study endocrine effects of air pollution, heavy metals, and solvents. In addition, some researchers use statistical models to understand the amount of exposure required for adverse health effects to occur.
NIEHS-funded research topics include:
- Identifying diseases and dysfunctions that were not previously known to be linked with endocrine disruptors
- Understanding how these chemicals affect health by studying the active sites, pathways, and biological mechanisms
- Understanding when, during the life span, exposure to EDCs may cause health problems
- 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.