January 9, 2004
“Why do women between the age of 20 to 40 years have higher levels of dibutyl-phthalate (DBP) in their bodies than anyone else?” asks a web site devoted to attacking the use of phthalates in cosmetics.
The answer, it turns out, is that they don’t, according to a new and more detailed analysis of data generated by the Centers for Disease Control and Prevention (CDC). The average levels of DBP to which women aged 20-39 are exposed are the same as for other women, the CDC data show—and far below safety levels set by the federal government.
For the last two years, this claim has been a linchpin to a publicity campaign against the use of phthalates in personal care products. The claim, trumpeted on the Internet and in full-page ads in newspapers such as The New York Times, was based on some preliminary data from CDC’s biomonitoring study of environmental chemicals in the U.S. population. Urine samples from 289 subjects in the CDC database did indeed show higher levels of the metabolite of DBP in a small number of women aged 20 to 39. But CDC warned at the time that the individuals who made up the sample were not representative of the population as a whole, and that the applicability of data was limited because the sample was so small. Nevertheless, a group of activist organizations built a whole campaign around the data.
Now a team of scientists from the CDC has broken out the data for that female age group from the entire CDC database of 2,500 people, yielding evidence that is representative of the U.S. population as a whole and statistically more reliable due to the greater number of people sampled. The results, now published in Environmental Health Perspectives, found that “women of reproductive age (i.e., 20 to 39 years of age) had concentrations similar to adolescent girls and women aged 40 years and older.” Average levels of DBP metabolites in urine samples from women are higher than in samples from men, but the corresponding DBP exposures are, on average, nearly 90 times lower than the safety level established by the U.S. government.
In short, a major premise for the attack on the use of phthalates in personal care products is not valid. “It was clear from the first,” said Marian Stanley, manager of the Phthalates Esters Panel of the American Chemistry Council, “that a major premise of the anti-phthalate campaign was dubious, because the sample was small and not representative of the population as a whole. Now we know the campaign is not supported by the CDC data.”
The study otherwise matches the data on phthalate metabolite levels reported by CDC last January. When converted to exposure levels, both this study and the original CDC study show that average levels for all phthalates are far below safety levels set by federal agencies.
