(CBS/ AP) The first major study of health effects in people from a chemical used in plastic baby bottles, food cans and a host of other products links it with possible risks for heart disease and diabetes.
It suggests a potential new concern about the safety of bisphenol A or BPA. And because of the possible public health implications, the results "deserve scientific follow-up," the study authors said.
But the study is preliminary, far from proof that the chemical causes heart disease and diabetes. Two Dartmouth College analysts of medical research said the study raises questions but provides no answers about whether the ubiquitous chemical is harmful.
The findings were released to coincide with the researchers' presentation of their findings at a Food and Drug Administration scientific advisers' hearing.
The FDA has the power to limit use of BPA in food containers and medical devices but last month released an internal report concluding that BPA exposure is not enough to warrant action.
Since then, another government agency released a separate report concluding that risks to people, in particular to infants and children, cannot be ruled out.
BPA is "everywhere," CBS News medical correspondent Dr. Jon Lapook said Tuesday on The Early Show.
"More than 90 percent of us have it in our body and the question is: is it safe?" LaPook said. "And the problem is that most of the studies are in rats and mice which have shown it can do some harm. It acts like an estrogen. It can mimic estrogen in the body. And so you can effect breast development, you can maybe change the timing of puberty but that's in rats. What about man? Well two weeks ago, for the first time, there was a study of monkeys showing it can affect brain development. This has heated up the controversy and this afternoon the FDA is going to meet about it."
Past animal studies have suggested reproductive and hormone-related problems from BPA. The new study is the largest to examine possible BPA effects in people and the first suggesting a direct link to heart disease, said scientists Frederick vom Saal and John Peterson Myers, both longtime critics of the chemical.
They wrote an editorial accompanying the study, which was published in the Journal of the American Medical Association. Still, they said more rigorous studies are needed to confirm the results.
Vom Saal is a biological sciences professor at University of Missouri who has served as an expert witness and consultant on BPA litigation. Myers is chief scientist at Environmental Health Sciences, a Charlottesville, Va., nonprofit group.
BPA is used in hardened plastics in a wide range of consumer goods including food containers, eyeglass lenses and compact discs. Many scientists believe it can act like the hormone estrogen, and animal studies have linked it with breast, prostate and reproductive system problems and some cancers.
Researchers from Britain and the University of Iowa examined a U.S. government health survey of 1,455 American adults who gave urine samples in 2003-04 and reported whether they had any of several common diseases.
Participants were divided into four groups based on BPA urine amounts; more than 90 percent had detectable BPA in their urine.
A total of 79 had heart attacks, chest pain or other types of cardiovascular disease and 136 had diabetes. There were more than twice as many people with heart disease or diabetes in the highest BPA group than in the lowest BPA group. The study showed no connection between BPA and other ailments, including cancer.
No one in the study had BPA urine amounts showing higher than recommended exposure levels, said co-author Dr. David Melzer, a University of Exeter researcher.
Drs. Lisa Schwartz and Steven Woloshin of the Dartmouth Institute for Health Policy and Clinical Practice said the study presents no clear information about what might have caused participants' heart disease and diabetes.
"Measuring who has disease and high BPA levels at a single point in time cannot tell you which comes first," Schwartz said.
The study authors acknowledge that it's impossible to rule out that people who already have heart disease or diabetes are somehow more vulnerable to having BPA show up in their urine.
"There's a small possibility that there's some other factor that's explaining this and it's not due to BPA itself. We've done everything we can think of to exclude that possibility, but it would be nice to get more direct evidence," Melzer said.
The American Chemistry Council, an industry trade group, said the study is flawed, has substantial limitations and proves nothing.
"As the authors themselves note, they do not conclude that the presence of BPA is causing adverse health effects - they merely noted a statistical association," the group said in a statement.
But Dr. Ana Soto of Tufts University said the study raises enough concerns to warrant government action to limit BPA exposure.
"We shouldn't wait until further studies are done in order to act in protecting humans," said Soto, who has called for more restrictions in the past.
An earlier lab experiment with human fat tissue found that BPA can interfere with a hormone involved in protecting against diabetes, heart disease and obesity. That study appeared online last month in Environmental Health Perspectives, a monthly journal published by the National Institutes of Health.
Government toxicology experts have also studied BPA and recently completed their own report based on earlier animal studies. They found no strong evidence of health hazards from BPA, but said there was "some concern" about possible effects on the brain in fetuses, infants and children.
Several states are considering restricting BPA use, some manufacturers have begun promoting BPA-free baby bottles, and some stores are phasing out baby products containing the chemical. The European Union has said BPA-containing products are safe, but Canada's government has proposed banning the sale of baby bottles with BPA as a precaution.
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