Dibutyl,Dimethyl,and Diethyl Phthalate and Butyl Benzyl Phthalate

Conclusion

In a 1985 safety assessment of dibutyl, diethyl, and dimethyl phthalate, the Cosmetic Ingredient Review Expert Panel stated that these ingredients are safe for use in cosmetics in the present practice of use and concentration. ¹ Subsequently, in 2005, the Panel conducted an extensive rereview of the newly available studies since that assessment, confirmed the decision, and determined to not reopen that report. ² In 1992, butyl benzyl phthalate was found safe in the present practice of use and concentration. ³ The Panel reviewed studies performed since that assessment as well as updated the use and concentration data in 2007 and confirmed that conclusion. ⁴ In 2012, the Panel reviewed 3 new studies on phthalates published in 2012 and confirmed that dibutyl, dimethyl, and diethyl phthalate and butyl benzyl phthalate are safe in cosmetics in the present practices of use and concentration. The Panel did not reopen the safety assessment.

Discussion

The Panel reviewed new studies that focused on the potential for endocrine disruption/reproductive and developmental toxicity on dibutyl, dimethyl, and diethyl phthalate and butyl benzyl phthalate. One study of children aged 5 to 9, who were part of a Manhattan-Bronx cohort, revealed detectable, although varied, levels of phthalates in the urine of all 244 study participants. ⁵ Higher levels of both diethyl phthalate and butyl benzyl phthalate were associated with airway inflammation.

Two studies addressed diabetes and phthalates. In 1 study, there were 1,015 men and women 70 years of age from Uppsala, Sweden. ⁶ One sample per participant was collected from 2001 to 2004 and analyzed 5 to 8 years later. In this study, blood levels for dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, and diethylhexyl phthalate were measured and correlated with measures of insulin resistance and poor insulin secretion in nondiabetic participants.

In the second study, urinary concentrations of phthalate metabolites measured by the Centers for Disease Control and Prevention and self-reported diabetes in 2,350 women aged 20 to <80 participating in the National Health and Nutrition Examination Survey (NHANES) (2001-2008) were used. ⁷ The odds ratio for diabetes in women with higher levels of n-butyl phthalate, isobutyl phthalate, benzyl phthalate, 3-carboxypropyl phthalate, and the sum of diethylhexyl phthalate metabolites was greater than the odds ratio for women with the lowest concentrations of these phthalates.

The Panel noted that all of these studies identified associations between phthalate metabolites and either diabetes or airway inflammation. Such studies did not suggest a causal link between phthalates and any adverse outcome. The possibility that phthalate metabolites may impact peroxisome proliferation pathways was suggested in the diabetes studies, but that mechanism is not established as a mode of action. The Panel agreed that that there is a need for further study of the reported association between phthalates exposures and diabetes and to investigate possible causal links.