* Children with higher levels of BPA more likely to be obese
* Researchers theorize chemical could disrupt metabolism
By Genevra and Pittman
NEW YORK, Sept 18 (Reuters Health) - Children and teens who
had higher levels of the chemical bisphenol A in their urine
were more likely to be overweight or obese th an children with
lower levels, U .S . researchers said on Tuesday.
The findings do not prove that BPA, a type of synthetic
estrogen, causes children to gain weight. B u t r esearchers said
h ormone-like chemicals co uld be on e re ason for an increase in
childhood obesity, besides di et and exercise.
"Children are uniquely vulnerable to environmental
chemicals," said Dr. Leonardo Trasande of New York University
School of Medicine, who worked on the study published in the
Journal of the American Medical Association.
Trasande theorized that ingesting extra BPA could throw off
young people's hormonal balance and disrupt their metabolism.
BPA has already been banned in the United States from baby
bottles and sippy cups, but the U.S. Food and Drug
Administration has not banned the chemical from aluminum cans
and other types of packaging because it has not been
definitively shown to cause harm to adults.
Other studies have suggested a link between BPA and higher
weight in adults.
Trasande and colleagues analyzed data from a nationwide
health and nutrition survey conducted between 2003 and 2008.
Nearly 3,000 subjects ages 6 to 19 were weighed, measured and
had their urine tested for BPA. They also answered a range of
diet and lifestyle questions.
In total, about one-third of the children were overweight
and 18 percent were obese.
The researchers found that slightly more than 10 percent of
children with the lowest BPA levels were obese, compared to 22
percent of those with the highest BPA levels.
That was after taking into account how much the children
ate, their age, race and gender.
Trasande said he was struck by the strength of that link,
but it does not mean extra BPA in children's diets was
responsible for the extra pounds they were carrying.
There are a couple of other theories, Trasande said.
"Obese children could ingest food that has higher BPA
content - it could be what we call reverse causation," he said.
Or, they could have higher BPA stored up in their bodies and
release more BPA.
"Those are both very plausible explanations," he said.
Of course, an unhealthy diet and poor physical activity "are
still the biggest causes of childhood obesity," Trasande said.
Karin Michels, an epidemiologist from the Harvard School of
Public Health in Boston, agreed there is "accumulating evidence"
that BPA may be linked to obesity and related diseases like
diabetes - although most of that research was conducted on
Her own study, which used similar health and nutrition data,
found a link between BPA levels in urine and adult weight.
"We still don't really know how safe bisphenol A is," said
Michels, who was not involved with Trasande's study.
While more research is underway, Michels said it makes sense
to avoid polycarbonate bottles, aluminum cans and other products
containing BPA if there are other options.
"I think we should be on the safe side," she said. But, "I
don't think we have to panic about it at this point."
SOURCE: bit.ly/JjFzqx Journal of the American Medical
Association, online September 18, 2012.
(Editing by Christine Soares and Stacey Joyce)