They analyzed urinary concentrations of phthalates in 2,350 American women, between 20 and 80 years of age, who participated in the National Health and Nutrition Examination Survey (NHANES) between 2001-2008. After having adjusted their results for potential confounders, they found that women with higher levels of phthalate metabolites in their urine were more likely to have diabetes.
The lead researcher of the BWH study, Dr. Tamarra James-Todd, noted herself that this exploratory research had “a number of limitations.” In particular, as phthalates are known to be in certain types of medications and medical devices, including medical products containing polyvinyl chloride used in intravenous bags and medical tubing, the possibility of reverse causation cannot be ruled out. “As such, it is possible that some of these associations are due to greater exposure to phthalates through increased use of certain medical devices and medications among women with diabetes.”
Linda Loretz, PhD, Director, Safety and Regulatory Toxicology at the Personal Care Products Council (PCPC), the main trade association representing the cosmetics industry in the U.S. also pointed the fact that while “diethyl phthalate, also known as DEP, is the only phthalate with significant use in cosmetics, the BWH study found no association between DEP and diabetes in any of the four models used by the study’s authors.”
The Cosmetic Toiletry & Perfumery Association (CTPA), the UK cosmetic trade association, also noted that “of the particular phthalates mentioned in the study and the reports (mono-benzyl phthalate, mono-isobutyl phthalate, mono-n-butyl phthalate and di-2-ethylhexyl phthalate), di-2-ethylhexyl phthalate is banned from use in cosmetic products in Europe and we are not aware that any of the others are used in cosmetic products.”
Further research needed
The organisations representing the industry underline that while the study associated urinary levels of several phthalates with prevalent diabetes, no direct links have been found between diabetes and the use of phthalates in personal care products.
As for the authors of the research, they consider that “future prospective studies are needed to further explore these associations to determine whether phthalate exposure can alter glucose metabolism, and increase the risk of insulin resistance and diabetes.”