The list of health problems that scientists can confidently link exposure to endocrine disrupting chemicals has grown to include diabetes, cardiovascular disease and obesity, a new scientific statement suggests. The statement, released today by the Endocrine Society, also adds support for the somewhat controversial idea that even small doses of these chemicals can interfere with the activity of natural hormones, which play a major role in regulation of the physiology and behavior.
But the report, which updates a similar report published in 09, is the criticism of drawing the chemical industry.
a summary of the new report, which summarizes 1300 studies on endocrine disruptors, postulates that scientists are more confident than ever to tie these substances to a host of known health problems, including reproductive and development problems, thyroid deficiency, certain cancers of the reproductive and neurodevelopmental problems such as reduced IQ. But studies suggest these links can now be extended to heart and weight problems and diabetes, explains the first author of the abstract, Andrea C. Gore, professor of pharmacology and toxicology at the University of Texas, Austin. It was six years ago, scientists could not make such a case for these strong ties, Gore said, because there was not enough good studies. "But it really was an emerging area where there is evidence much stronger now," said Gore reporters today a conference call.
Yet some toxicologists and industry groups have long disputed the assertion that endocrine disruptors can trigger effects in small doses; this idea can be difficult to test in laboratory animals, which are generally exposed to high doses in toxicology studies. And critics of the new report say it does not seem to clarify the vagueness of the 09 version of what it means for an endocrine disruptor to cause a "negative effect".
The summary of the new report "is broad, unsupported claims about the relationship between chemicals and disease," the American Chemistry Council, the largest trade group for the industry chemicals, argued in a statement. Regulatory agencies such as the Environmental Protection Agency (EPA) has still not accepted the idea that minute doses of endocrine disruptors can cause health problems, the industry group based in Washington, DC, said. And the Endocrine Society failed to specify when a chemical causes a "negative effect" scientifically proven counsel argues (against only show endocrine activity).
The National Research Council has launched a multi-year review whether the current EPA chemical assessment practice properly capture endocrine effects at low doses. Meanwhile, Gore rejects the criticism that the Endocrine Society has not adequately defined the "negative effects". It notes that, in studies on laboratory animals, some toxicologists believe wrongly that endocrine disruptors must-related health problems show immediately. But these health problems can take years or even decades to manifest in men, she said, and months in laboratory animals. And the specific disease that chemicals can induce in animals is often not always known from the beginning of the study, she added. "I think the problem has been solved for many endocrinologists and toxicologists," she said.
The Endocrine Society summary strongly emphasizes studies of bisphenol A (BPA), phthalates, persistent organic pollutants such as polychlorinated biphenyl ethers, and flame retardants such as polybrominated diphenyl ethers. "These chemicals have the greatest depth and breadth of information available," says the summary.
But the summary adds that most industrial chemicals released into the environment numbering in the tens of thousands-have never been tested for potential endocrine disruptor. in addition, Gore said, scientists are increasingly finding that some chemical alternatives to BPA and other EDCs suspected endocrine disruptor potential display themselves. These findings the summary said, highlighting the need to test chemicals before entering the trade and to better educate the public and policy makers on how to prevent exposures.
emerging test methods such as high-throughput screening assays could help researchers identify which of the thousands of chemicals in the environment now need more scientific control, the summary suggests. (EPA currently studying the use of these methods for prioritizing chemicals deserves animal testing for the full effects of endocrine disruptors.)
The Endocrine Society also calls for more research funding endocrinology, general, arguing that the benefits the company will far outweigh the costs. Funding agencies should focus on projects "science team", and not just individual studies by individual scientists, the summary submitted.
The company recommends several expansion of research areas. Researchers should increase the range of studied hormone-receptor proteins that receive chemical signals from hormones to see how endocrine disruptors may affect them. And future research could target more specific responses to gender and the effects of mixtures of several endocrine disruptors, the summary said.
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