Common chemical tied to thyroid hormone shifts
By Sandy Kleffman, MCT
October 9, 2012, 12:00 am TWN
WALNUT CREEK, California--A chemical found in many common products, including plastic bottles and canned food linings, is linked in a new study to thyroid hormone changes in pregnant women and baby boys.
The findings raise concerns because thyroid hormones play a crucial role in growth and brain development in young children, health experts note.
The study by University of California, Berkeley researchers is the first to analyze the effect of bisphenol A, or BPA, on thyroid hormone levels in pregnant women and newborns.
“We are finding associations, so that is giving us concern, but I do think people need to know that we're still really learning about how BPA may impact the health of people,” said Kim Harley, a study co-author and associate director of UC Berkeley's Center for Environmental Research and Children's Health.
“There's a lot more to learn, and I don't know that we have any answers yet,” Harley said.
BPA has drawn increased scrutiny in recent years as the public has become aware of how easy it is to be exposed to the estrogen-like compound and how little is known about the health effects.
Studies have shown that more than 90 percent of American women of childbearing age have BPA in their urine.
The chemical is in many plastic bottles, dental sealants, resins in the lining of food and beverage cans, and some sales receipts.
Last year, California lawmakers banned manufacturers from including BPA at levels above 0.1 parts per billion in bottles or cups designed for children younger than 3, beginning July 1, 2013.
In July, the U.S. Food and Drug Administration followed suit by prohibiting the chemical in baby bottles and cups. Many manufacturers had already begun phasing out BPA in such products.