Over the last two decades, rates of obesity have significantly increased in the United States. About a third of adults in the U.S. are obese, which puts them at risk for conditions such as heart disease, stroke, type 2 diabetes, and certain types of cancer.
Although nutrition, activity level, and genetics all play important roles in the development of obesity, there is increasing evidence that exposure to chemicals called “obesogens” may alter metabolism and predispose some people to gaining more weight. Environmental health scientists are studying how environmental exposures — especially those that occur during critical windows of development — influence weight gain, metabolism, obesity, diabetes, and related conditions.
What NIEHS is Doing
NIEHS-funded researchers are using animal models and epidemiological studies to better understand how exposures to air pollution and other environmental contaminants might increase risk for obesity, diabetes, and metabolic dysfunction. Chemicals under study include, but are not limited to, bisphenol A, polychlorinated biphenyls (PCBs), dioxins, arsenic, pesticides, phthalates, and perfluorooctanoic acid. Researchers are examining exposures to individual contaminants as well as the effects of mixtures.
NIEHS-funded researchers are also identifying new obesogens and working to understand how chemical exposures affect diabetes and liver lipid disorders and how they may disrupt metabolism in a way that leads to metabolic syndrome, a group of factors that raises risk for heart disease and other health problems.
NIEHS-funded researchers who focus on the developmental origins of obesity and metabolic dysfunction are examining the effects of both prenatal and preconception exposures. The importance of adult exposures, interactions between developmental and adult exposures, and transmission of effects across generations are also important research areas. In addition, researchers are examining susceptibility to weight gain under various lifestyle conditions because in some cases, the effects of developmental exposure to environmental chemicals do not manifest until after a later “hit,” or challenge, such as eating a high fat diet.
This research will help achieve a better understanding of the role of environmental factors in obesity and diabetes, which is necessary for developing prevention strategies. Identifying and eliminating obesogens might even help reverse today’s trend of increasing obesity.