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FDA Relied on Industry Studies to Judge Chemical Safety

Posted on: Saturday, 22 March 2008, 03:00 CDT

Ignoring hundreds of government and academic studies showing a chemical commonly found in plastic can be harmful to lab animals at low doses, the Food and Drug Administration determined the chemical was safe based on just two industry-funded studies that didn't find harm.

In response to a congressional inquiry, Stephen Mason, the FDA's acting assistant commissioner for legislation, wrote in a letter that his agency's claim relied on two pivotal studies sponsored by the Society of the Plastics Industry, a subsidiary of the American Chemistry Council.

One of the studies has never been published, and therefore never subjected to peer review; the second has been heavily criticized by researchers who say the results are inconclusive because of flawed experimental methods.

"The FDA is really going to have problems over this," said Frederick vom Saal, a bisphenol A researcher at the University of Missouri-Columbia.

In January, Michigan Democrats Rep. John Dingell, chairman of the House Committee on Energy and Commerce, and Rep. Bart Stupak, who leads a subcommittee, launched an investigation into the use of bisphenol A in cans containing baby formula and other products aimed at infants and toddlers.

Studies have shown that bisphenol A causes breast cancer, testicular cancer, diabetes and hyperactivity in laboratory animals. Two government panels, including one that has come under fire as being biased in favor of chemical-makers, have warned that bisphenol A might be dangerous to developing fetuses and children younger than 3.

Bisphenol A was developed in 1891 as a synthetic estrogen but came into widespread use in the 1950s when scientists realized it could be used to make polycarbonate plastic and some epoxy resins to line food and beverage cans. More than 6 billion pounds of bisphenol A are produced annually in the United States, for use in an array of products, including dental sealants and baby bottles.

The chemical has been found in the urine of 93% of Americans tested.

Companies questioned

The Michigan politicians sent letters to seven major manufacturers of infant formula, including Nestle USA and Abbott, demanding answers about the companies' use and knowledge of the chemical bisphenol A.

They also sent a letter to the FDA, requiring the agency's commissioner to show the scientific support for its position on the chemical's safety.

On Feb. 25, the FDA responded. The letter appeared on the Web site of the House Energy and Commerce Committee this week.

According to the letter, the FDA based its claim that there is no "safety concern at the current exposure level" on its own studies, conducted in the 1990s, which indicated that people were exposed to small amounts of the chemical.

They gathered that information by testing products such as aluminum cans and baby bottles to see how much of the chemical was leaching. Then they looked to the two chemical industry studies to see if those exposure levels could cause harm.

The two studies said the chemical caused no harm to rodents at low doses.

Effects on rats

One of those studies has been criticized by researchers who say it contained flawed experimental methods.

Because bisphenol A is believed to behave like the hormone estrogen, scientists need to show that the animals they are using in an experiment will respond to estrogen. If they don't, then it is unlikely that they will respond to bisphenol A, either.

Some research indicates that one strain of rat, the Charles River Sprague-Dawley rat, responds to estrogen only at high doses -- doses higher then what's typically found in a birth control pill.

The industry study that the FDA relied on looked at the effects of bisphenol A on Sprague-Dawley rats, but neglected to expose any rats in the experiment to estradiol, a strong synthetic estrogen. Therefore, critics of the paper say the results are inconclusive.

Surprised by admission

Anila Jacob, a senior scientist at the Environmental Working Group, a Washington, D.C.-based watchdog group, said she was surprised that the FDA so openly admitted to relying on those two studies, particularly when one of them has never been published or released to the scientific world for review.

"There's a lack of transparency here," she said, adding that the agency's reliance on these studies "doesn't serve the public."

Officials at the FDA or the House Energy and Commerce Committee could not be reached for comment Friday.

In December, the Journal Sentinel reported that another government program, the National Toxicology Program, gave more weight to industry-funded studies and more leeway to industry-funded researchers in its review of the chemical.

Source: The Milwaukee Journal Sentinel

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