In general, the causes of type 2 diabetes are pretty clear — a lack of exercise, a poor diet, genes, and ethnicity are the most serious risk factors for the disease. But now that more than 26 million Americans have diabetes and 70 million more are prediabetic, researchers are also focusing on otherfactors that might also contribute to a person’s risk of developing diabetes.
One of the latest possible culprits thought to be contributing to the diabetes epidemic is chemicals in the environment and in products we use every day. Some chemicals might contribute to diabetes risk independently while others might contribute to obesity risk, which is a serious factor in the development of type 2 diabetes. As of now, research on whether chemicals contribute to any and all types of diabetes is still in very preliminary stages. Here’s what we know now.

The Relationship Between Chemicals and Diabetes

“There is an association between some chemicals in the environment and diabetes,” says Kristina Thayer, PhD, director of the National Toxicology Program Center for the Evaluation of Risks to Human Reproduction in Durham, N.C., part of the U.S. Department of Health and Human Services. “What we don’t know is whether it’s causal.” That means that while a number of studies might show that if you had a higher level of a certain chemical you were more likely to have diabetes, it’s not yet clear whether that chemical exposure preceded the diabetes. More research is needed to better establish cause and effect.
As far as specific chemical culprits, phthalates, a common chemical found in soaps, nail polishes, hair sprays, perfumes, and moisturizers, might top the list. In a study published in the journal Environmental Health Perspectives, researchers found that women with the highest levels of phthalates in their urine had a risk of diabetes that was 70 percent higher than women with the lowest levels of phthalates in their bodies.
Another possible chemical cause of diabetes is arsenic. Areas of Bangladesh and Taiwan have well documentedhigh levels of arsenic in drinking water, Scientists in those areas have found a strong association between diabetes and people who drink the water, Thayer says. In the United States, the Environmental Protection Agency regulates chemicals like arsenic, so Americans do not have nearly the exposure of people in those other areas. As levels of arsenic decrease to the low-to-moderate range, researchers found the literature becomes less consistent with an association with diabetes.
Polychlorinated biphenyls, or PCBs, and dioxins are among other chemicals examined and found to have at least some association with diabetes. However, the issue of causality was much less clear. “A lot of the chemicals are very persistent because they stay in fat — that’s where they’re stored in the body,” Thayer says. “If you have someone overweight or obese, which is its own independent risk factor for diabetes, that person is probably going to have higher levels of these chemicals in their fat. It’s hard to disentangle the effect of the chemical versus the health condition of being overweight or obese.” Separately, PCBs, which were banned by the Environmental Protection Agency in 1979, but still exist in the environment, have been linked to obesity in adults.
Much more research needs to be done to establish how these and other chemicals affect our bodies — and our diabetes risk — Thayer says. For now, she says environmental factors shouldn’t be the top concern of someone who is at risk for diabetes.
“Diabetes could be caused by a number of factors, probably a combination of factors, and it’s possible a chemical in the environment might be an added risk factor,” she explains. “The best way consumers can act on it now is to work on healthy behaviors under their control, which is managing what they eat, how much they eat, and making sure to exercise.”