Harm from Plastic Additive Challenged: Early exposure shows no ill effects

A chemical used to soften plastics and that has been suspected of disrupting development showed no long-term effects in a small study of teens. As newborns, the young people had each received intensive medical care that used plastic tubing and bags bearing the chemical. If more-comprehensive studies support the new finding, the chemical, di-2-ethylhexyl phthalate (DEHP), may be deemed harmless to newborns.

DEHP and some other phthalates can leach from plastics. In animal studies, DEHP exposure during development causes reproductive abnormalities, such as undersize and malformed testes.

Since DEHP is used widely in hospital equipment, toxicologists have pegged phthalate as a possible danger to fetuses and infants (SN: 9/2/00, p. 152: New Concerns about Phthalates).

To get a sense of whether DEHP exposure has long-term developmental effects, researchers at Children’s National Medical Center in Washington, D.C., studied 19 teenage volunteers who had received lifesaving treatment in intensive care units shortly after birth. Because of lung infections or other problems, the infants couldn’t properly transfer oxygen from their lungs to blood cells, so each spent at least several days attached to blood-oxygenating equipment that repeatedly circulated their blood through plastic tubing. Past studies indicate that this procedure typically exposes infants to high doses of DEHP.

The researchers examined the teenagers’ height and weight, biochemical measures of several organs, and concentrations of important sex and growth hormones, including testosterone and estradiol. For all these measures, the volunteers had values within the ranges typical for their age and sex, Khodayar Rais-Bahrami and his colleagues report in an upcoming Environmental Health Perspectives.

Other researchers find the new study encouraging but are quick to point out its limitations. “It doesn’t look like the kids have anything untoward,” says Paul Foster of the National Institute of Environmental Health Sciences in Research Triangle Park, N.C. But since DEHP concentrations were not measured in the volunteers when they were newborns, it’s uncertain whether all the volunteers were actually exposed. The study also suffers from its small size and the lack of data from a comparison group of teenagers that had not been exposed to DEHP as newborns, he says.

L. Earl Gray of the Environmental Protection Agency in Research Triangle Park, N.C., notes that subtle changes in internal tissues wouldn’t be evident in the recent study. Nevertheless, he adds, “it’s important that in this small population there are not gross problems.”

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