Zoeller co-authors UN report on global danger of hormone disruptors

Featured in the CNS Newsletter: Issue 4 - March 2013

Photo of Professor Thomas Zoeller

Biologist Thomas Zoeller coauthored a report that shows evidence linking hormone-mimicking chemicals to human health problems has grown stronger over the past decade, becoming a "global threat" that should be addressed.

The report, written by an international team of experts, is a joint effort by the World Health Organization and the United Nations Environment Programme to give policymakers the latest information on chemicals with a likelihood of affecting hormones in people and wildlife.

"Over the past decade, we know much better that chronic diseases, ones related to the endocrine system, are increasing globally," said Zoeller. He said the goal of the report is to update world leaders on this complex topic with controversial implications.

The report shows a rise in endocrine-related diseases and disorders. There is now "emerging evidence for adverse reproductive outcomes" and "mounting evidence" for effects on thyroids, brains and metabolism, the report summary says.

Such diseases include male reproductive problems, pregnancy complications, certain cancers, obesity, and brain development. Fetuses, babies and young children are the most vulnerable to hormone-altering chemicals since their bodies are still developing.

Many factors can cause these diseases, but given how fast some are rising, the report concludes that environmental chemicals are playing a role.

A decade ago the biggest threat was thought to be persistent organic pollutant chemicals – such as DDT and polychlorinated biphenyls (PCBs). These chemicals – now banned in the United States – traveled the globe, persisted in the environment and caused severe population declines in some wildlife species.

Such contaminants still pose a threat. However, less persistent but more ubiquitous chemicals found in everyday products – such as bisphenol A (BPA) and phthalates – now are increasingly linked to human health problems.

"Frankly, for BPA, the science is done. Flame retardants, phthalates … the science is done," Zoeller said. "We have more than enough information on these chemicals to make the reasonable decision to ban, or at least take steps to limit exposure."

Government agencies and industry groups remain unconvinced, and have taken no actions.

For more information and to read the report summary, go to the Scientific American article.

Watch the video of Thomas Zoeller's Distinguished Faculty Lecture, "The Brain on Endocrine Disrupting Chemicals," which he gave on February 25, 2013.