NEW YORK (AP) — A provocative new study suggests a connection between the BPA chemical used in food packaging and childhood obesity, but the researchers say their findings don’t prove it’s the cause.
While most people have traces of the plastics chemical in their bodies, the study found that children with the highest levels in their urine were twice as likely to be obese as those with the lowest.
There are other factors that could explain the results, and many reasons why children gain too much weight, the researchers said.
“Clearly, unhealthy diet and poor physical activity are the leading factors contributing to obesity in the United States, especially in children,” said Dr. Leonardo Trasande of New York University, the lead author.
But the study does hint that causes of childhood obesity may be more complicated, he added. He said it is the first national research to tie a chemical from the environment to childhood obesity and seems to echo what some studies have seen in adults.
One puzzling result: Significant differences were detected only in white children. For black and Hispanic kids, obesity rates were similar for those with the lowest levels of BPA as those with the largest amount. The researchers couldn’t explain that finding.
The study was released Tuesday and is in Wednesday’s issue of the Journal of the American Medical Association.
BPA, or bisphenol A, has been used since the 1960s and has become so widespread that it’s found in virtually all Americans. Government health officials have deemed low levels of it to be safe but haven’t been able to decide what amount of BPA — if any — would be a health concern.
BPA is used to make hard plastics for food and beverage containers and many consumer goods and for metal can linings. Environmental groups have worried that it interferes with children’s development. Makers of baby bottles and sippy cups stopped using it, and this year the Food and Drug Administration announced it could no longer be used in those baby products.
Some experimental studies on animals have found that BPA can aid obesity by disrupting metabolism and helping to make fat cells larger. And studies have suggested a possible tie between urinary BPA levels and obesity-related illnesses in adults, including diabetes and heart disease.
In the new study, Dr. Trasande and his colleagues used information from an annual federal health survey, which includes weighing and measuring participants and taking blood and urine samples.
Their study involved more than 2,800 children ages 6 through 19, who took the survey in the years 2003 through 2008. They compared BPA levels in their urine to their weight and divided them into four groups based on BPA amounts.
The key finding: About 22 percent of the children with the highest levels of BPA were obese, compared with just 10 percent of kids with the lowest levels.
Was the reverse true? Did the heaviest kids have more BPA in their urine, and the thinnest kids less? Yes, Dr. Trasande said. But he did not include those numbers in his study and declined to provide them.
The study raised more questions than it answered: