Study ties BPA in cans and bottles to childhood obesity

Children with higher levels of bisphenol A are more likely to be obese, according to a new U.S. study of nearly 3,000 children and adolescents.

The manufactured chemical, known as BPA, is typically found in plastic consumer products such as water bottles. Its use is restricted in Canada in products such as baby bottles and sippy cups, over concerns it mimics the hormone estrogen.

However the new study published Tuesday in the Journal of the American Medical Association, suggests “ubiquitous” exposure to BPA may be linked to obesity in age children.

The researchers studied 2,838 children from the ages of six to 19, between 2003 to 2008, and found that the higher the concentration of BPA in their urine, the more likely they were to be obese.

The participants were divided into four groups depending on their level of urinary BPA. Those in the lowest group had a 10.3 per cent prevalence of obesity, while those in the group with the highest level had a 22.3 per cent prevalence of obesity.

“To our knowledge, this is the first report of an association of an environmental chemical exposure with childhood obesity in a nationally representative sample,” the authors wrote.

Interestingly, the study points out that when the results were broken down by ethnicity, it became clear that the BPA-obesity trend was only present in the white children and adolescents in the study. In children from other ethnicities there was no clear relationship between BPA levels and obesity.

The researchers were careful to point out that their findings don’t prove the cause of the higher rates of obesity, but only identified an apparent correlation to higher BPA levels.

There are many reasons why children become overweight, 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 lead author Dr. Leonardo Trasande of New York University.

But the study does suggest that the causes of childhood obesity may come down to more factors than just diet and exercise.

The study points out that the U.S. Food and Drug Administration has banned BPA use in baby bottles and sippy cups, but said the findings raise questions about exposure to BPA by adolescents and teens as well.

“Last year, the FDA declined to ban BPA in aluminum cans and other food packaging, announcing ‘reasonable steps to reduce human exposure to BPA in the human food supply’ and noting that it will continue to consider evidence on the safety of the chemical,” the study said.

“Carefully conducted longitudinal studies that assess the associations identified here will yield evidence many years in the future.”

According to a federal government fact sheet on chemical substances, “bisphenol A does not pose a risk to the general population, including adults, teenagers and children. Consumers can continue to use polycarbonate water bottles and consume canned foods and beverages, as the level of exposure from these products is very low.”

BPA was developed in the 1960s and is used in products ranging from hardened plastics to food packaging and metal cans.

The chemical is so widely used it can be found in some level in almost all Americans and Canadians, but environmental groups have raised concern in recent years that the chemical interferes with children’s development by mimicking estrogen.