MONDAY, Feb. 4, 2008 (HealthDay News) -- More than 80 percent of infants tested in a new study had been exposed to a potentially harmful group of chemicals known as phthalates.
Exactly what this means in terms of infant health isn't yet clear, however. Some animal studies have found these substances to be harmful to development, and one study on human infants found an association between exposure to a particular phthalate and male reproductive problems. Because the exact effects on the developing body aren't known, the researchers suggest limiting the use of products that contain these chemicals in infants as much as possible. Baby lotion, baby shampoo and baby powder were all linked to phthalate exposure in the study.
"Right now, we still don't know the true long-term effects," said study author Dr. Sheela Sathyanarayana, an acting assistant professor in the department of pediatrics at the University of Washington, Seattle. But, she added, it's probably a good idea to "decrease the amounts of products used, especially in newborns."
Phthalates are a group of widely used chemicals that make plastic softer and help stabilize fragrance in personal care products. These chemicals are found in children's toys, infant care products, cosmetics, food packaging, vinyl flooring, blood storage containers and more, according to the U.S. Centers for Disease Control and Prevention (CDC). Exposure to phthalates occurs when you use a product containing them, from breathing household dust containing phthalates, from medical treatments like dialysis that use products with phthalates, and from living near a manufacturing facility that uses phthalates, according to the CDC. Phthalates are banned from use in personal care products and in some toys in Europe.
For the current study, the researchers looked for nine different metabolites of phthalates in the urine of 163 infants born between 2000 and 2005. The reason they had to look for evidence of phthalate exposure in the urine is that it's difficult to measure exposure any other way because manufacturers aren't required to disclose all phthalates in their products.
"Right now, manufacturers aren't required to label them, so it's difficult to know if you're using a product with phthalates," explained Sathyanarayana.
Most of the infants studied -- 81 percent -- had detectable levels of phthalate metabolites. Because the researchers also asked the parents about which products had been used on the babies, they were also able to see an association between higher levels of phthalate metabolites and the use of baby shampoo, lotion and powder. Diaper creams and baby wipes didn't appear to increase the concentration of phthalate metabolites in the urine, according to Sathyanarayana.
Findings from the study are published in the February issue of Pediatrics.
"We believe that there is potential value in the study of metabolized phthalates. But we take great exception to any effort to draw unfounded conclusions that suggest human health risks are associated with the mere presence of very low levels of metabolized phthalates in urine," Marian Stanley, manager of the Phthalates Esters Panel of the American Chemistry Council, a plastics industry trade group, said in a statement.
"With phthalates in particular, there's good research in multiple animal studies that these compounds can be harmful. It's interesting that industry is willing to accept animal studies to introduce new medication, but when something is found to be harmful, industry says, 'Well, those studies were just done on rats,' " said Dr. Jonathan Weinkle, a physician at Children's Hospital of Pittsburgh and the University of Pittsburgh's Cancer Institute's Center for Environmental Oncology. "If animals are useful models for things that are helpful, it's because their bodies are similar enough to ours. Animal models should be reliable for good and bad."
Both Weinkle and Sathyanarayana said that dose makes a difference. The greater the exposure, the greater potential for harm, which is why they recommend limiting the use of products containing phthalates if possible. Sathyanarayana said that phthalates are often contained in fragrances, so a product that's fragrance-free may also be phthalate-free, and she said there are products available that are labeled phthalate-free, but they're generally more expensive.
The Environmental Working Group has a database of personal care products, including baby-care products, that evaluates whether individual products are likely to be safe.