Studies Examine If Household Chemicals Can Cause Diabetes

By Nicole Knight

More than 30 million Americans have diabetes, and another 84 million have prediabetes. While researchers have linked lifestyle factors and family history to the disease, they're now also exploring the possible role of common household chemicals called phthalates and bisphenol A (BPA).

Phthalates are found in a wide assortment of consumer goods, including cosmetics, nail polish, food packaging, detergent and even some medicines. A study published in the journal Environmental Health Perspectives found some phthalates may affect human development, and a specific phthalate may cause cancer. BPA, a commonly used phthalate in food containers and water bottles, may affect brain development in babies and children, according to MayoClinic.

Recent studies investigated whether these chemicals might be linked to the nation's diabetes epidemic.

In April 2019, a study published in the journal Molecular and Cellular Biochemistry was the first to demonstrate an association between high levels of BPA and cell aging, inflammation, insulin resistance and poor glycemic control in type 2 diabetes patients. Put simply, increased BPA levels may worsen symptoms of type 2 diabetes and lead to faster aging.

Another study published in the Environmental Science and Pollution Research journal in July 2019 determined that "BPA may be an environmental cofactor of diabetes," based on the urinary BPA levels of diabetics compared to that of non-diabetics.

Older studies also explored the association between household chemicals and diabetes. In a 2012 study, a research team from Brigham and Women's Hospital in Boston measured the amount of phthalates in the urine of 2,350 women nationwide.

They found that women with the highest quantities of two kinds of phthalates were nearly twice as likely to develop diabetes than women with the lowest levels of the two chemicals in their urine, Science Daily reported.

The authors also found the following links between various phthalates and diabetes:

• Women with the highest levels of the chemicals mono-benzyl phthalate and mono-isobutyl phthalate in their urine had almost twice the risk of diabetes when compared to women with the lowest levels of those chemicals.
• Women with moderately high levels of two phthalates — mono-n-butyl phthalate and di-2-ethylhexyl phthalate — had approximately a 70 percent higher risk of diabetes.
• Women with above-median levels of mono-(3-carboxypropyl) phthalate had a roughly 60 percent greater risk of diabetes.

The research was published in the journal Environmental Health Perspectives.  

The lead author, Tamarra James-Todd, Ph.D., cautioned that the paper doesn't show a causal relationship between the chemical and diabetes, but suggested the use of phthalates in medicine may help explain some high concentrations in women's urine. She said more studies are needed to understand the potential link between the chemical and diabetes.

Meanwhile, another study published in the same journal linked exposure to phthalates and BPA to diabetes in middle-aged women. The research builds on earlier studies in animals that suggested BPA exposure may affect cell and thyroid functions, interfere with glucose metabolism and play a role in liver dysfunction.