Baby Ills from Beauty Aids?

Last November, pregnant women had a reason to be glad they could no longer reach their toenails. Beauty Secrets, a report published by the Washington, D.C.-based Environmental Working Group (EWG), warned that women of reproductive age should avoid cosmetics containing dibutyl phthalate (DBP), a compound commonly used in nail polish and other beauty products. The month prior, in the October 2000 issue of EHP, scientists from the Centers for Disease Control and Prevention (CDC) and the National Toxicology Program (NTP) published results of tests on urine specimens collected through the Third National Health and Nutrition Examination Survey. The tests revealed that some of the highest concentrations of the DBP metabolite monobutyl phthalate turned up in women of child-bearing age.

The current DBP reference dose, set by the U.S. Environmental Protection Agency, is 100 micrograms per kilogram body weight per day. DBP has not been connected to birth defects in humans, but studies with rats have shown this phthalate to be antiandrogenic, suppressing hormones involved in male sexual development. Although male rats appear more sensitive to the effects of DBP, higher doses can induce effects such as high liver and kidney weights, hepatic lesions, and neural tube defects in females as well.

For years, scientists assumed that most human DBP exposure came primarily through the minute quantities found in the food chain. The CDC/NTP team, led by CDC researcher John Brock, now adds cosmetics as another possible source of exposure. DBP metabolite concentrations in the 289 adults studied suggest people are exposed frequently because the phthalate ester does not bioaccumulate and has a half-life of r less than 12 hours, says Brock.

Added to a variety of consumer products since the 1930s, DBP is used in cosmetics to reduce brittleness and cracking and as a "penetration enhancer" and emollient. But Beauty Secrets coauthor Jane Houlihan says neither women's exposure to DBP via cosmetics nor the human health effects of DBP exposure have ever been measured. Except for chemicals added directly to food, there is no legal requirement for health and safety testing or human exposure monitoring for any chemical in commerce, states the report, which adds, "The same chemicals, ironically, are often tightly regulated as pollutants."

The authors of Beauty Secrets read cosmetic labels both online and in drug stores. They found that ingredients were often listed in tiny print, inside the packaging, or not at all, despite Food and Drug Administration requirements. In addition, says Houlihan, manufacturers need not list fragrance ingredients (which may include DBP) or any chemical mixture considered to be a trade secret. This leaves consumers with "no practical way to choose products that are phthalate-free," says the report, which lists 37 DBP-containing and 4 DBP-free nail products.

The report suggests that phthalates should be considered as potential contributors to human health effects including hypospadias (misplacement of the urethral opening in the penis) and cryptorchidism (undescended testes). But studies on these defects have produced conflicting results, with some suggesting there has been no significant increase in hypospadias. Moreover, any increases in hypospadias may be due to other factors, such as the increased age at which women in the United States are having children.

Scientists--including those from the EWG--admit that connecting human birth defects to DBP is speculative. "There's a big difference between what humans are exposed to and what produces an effect in animals," says researcher Paul M. D. Foster of the Chemical Industry Institute of Toxicology, who has studied the teratogenic effects of DBP on rats.

Representatives of the cosmetics industry claim the amount of DBP in their products--about 5% by weight in nail polish, according to Houlihan--is too small to endanger users. "`Dose makes the poison,'" says Gerald McEwen, vice president of science for the Cosmetic, Toiletry, and Fragrance Association, a trade group based in Washington, D.C. "You can not have enough exposure to DBP from cosmetics to cause birth defects."

In March 2001, the CDC published the National Report on Human Exposure to Environmental Chemicals, which discusses monobutyl phthalate, among other chemicals [see "CDC Unveils Body Burden," this issue]. The results have not yet been broken down by age, so Brock can't say if they match his team's finding of high levels in reproductive-age women. He and others at the CDC are conducting a new study to identify the prime sources of DBP exposure. Michael Shelby, director of the NTP Center for the Evaluation of Risks to Human Reproduction and a coauthor of the EHP paper, expects the results to help consumers make their own decisions about using products with DBP. "We need to understand where those high exposures are coming from and why women of childbearing age have higher exposures," he says. "The public deserves some balanced information."