A new study in the journal Environmental Health Perspectives examines whether there is a connection between phthalates and diabetes in women. Researchers did find an association but did not prove that the chemicals cause diabetes.
Researchers found that the risk of having diabetes was twice as high in women with the highest levels of certain phthalates, compared with women with the lowest levels. Looking at the data a different way, there would be about 40 extra diabetes cases per 1,000 women when women with high levels are compared to women with low levels.
What explains this association? One idea is that phthalates bind to cells in the body that manage blood-glucose metabolism and fat cell development.
"Because they can bind to natural cell receptors, they could alter normal function," said Dr. Tamarra James-Todd, associate epidemiologist at Brigham and Women's Hospital in Boston.
Keep in mind that people with diabetes may have higher phthalate levels because of their use of certain medical devices and medications, which contain these chemicals, too. This study did not rule out that explanation.
But the researchers did a sub-study on women without diabetes to get at this issue. Non-diabetic women with higher levels of pthalates tended to have higher blood glucose levels. "Both of those things are precursors of diabetes," James-Todd said.