Canadian kids and teens with high levels of bisphenol A, or BPA, in their urine, are more likely to have behaviour problems, a new Statistics Canada study has found.
And while the researchers say their study was not able to show that the BPA is responsible for the behaviour problems, they say further research is needed to better understand the link.
BPA is a plastic ingredient commonly used as a resin on the interior of food cans, as well as in the production of plastic toys and dinnerware, dental composites, and other items.
It is rapidly broken down in the body and excreted in urine, which is why urine tests are considered the best way to measure recent exposure.
Using data from the Canadian Health Measures Survey, Statistics Canada researchers found that more than 90 per cent of the children and teens they tested had BPA in their urine. Previous studies in both Canada and the U.S. have found similar levels.
The researchers found that the higher the BPA concentration in the urine of boys, the higher their risk for behaviour problems. Among girls, high BPA concentration was linked to greater hyperactivity.
Kids and youth in low and lower-middle income households tended to have significantly higher BPA in their urine than those in higher-income households.
Kids exposed to second-hand smoke every day or almost every day also had higher BPA. So did younger children compared to those aged 15 to 17. But the BPA levels did not differ by ethnicity, the kids' gender or BMI, or the level of education in the household.
The researchers caution that the link they found between BPA and behaviour problems was "relatively weak." But they added that even a minor association could have public health implications and should be investigated further.
"A small effect at the population level can translate into a substantial number of children and youth at risk for behavioural difficulties," the authors write.
BPA has been linked to hormone disruption and brain development problems in several animal studies. Human studies have linked the chemical to cancer, miscarriage, and childhood obesity.
Concerns about the chemical prompted Canada to ban its use in baby bottles in 2008. The U.S. FDA followed suit in 2012.
But according to the head of the BPA Global Group, a division of the American Chemistry Council, the Statistics Canada study is no reason for concern.
"Parents can and should continue to confidently use products that depend on BPA," Steven G. Hentes said in a statement to CTV News.
Hentes cautioned that, as the study notes, other researchers have concluded that BPA is not harmful. He pointed out that the study's authors acknowledge the links between BPA and behavioural problems are "relatively weak."
"These results need to be put into context," Hentes said. "Health Canada continues to conclude that dietary exposure to BPA through food packaging is not expected to pose a health risk to the general population."
Earlier this year, the European Food Safety Authority also concluded that BPA is safe for all age groups at current exposure levels. It found that people in Europe are exposed to BPA at much lower levels than their Tolerable Daily Intake limits.
The authors of this latest study says that while there is no evidence BPA is directly causing behaviour problems in children, further research is needed "to understand the mechanisms by which it may be related to behavioural outcomes."
Maggie MacDonald, the toxics program manager at Environmental Defence, it’s "disconcerting" to see this link between a common pollutant and behavioural troubles in young people.
She says it's clear to her that BPA should be fully banned.
"Taking BPA out of baby bottles and sippy cups was a good step, but it is not enough, because youth are being exposed to this chemical on a continuing basis in Canada," she told CTV News.
MacDonald notes BPA is still on "thermal" paper receipts, which most people touch every day, and should also be removed from can linings and other plastics.
She adds that it is not enough to ban BPA and then replace it with alternatives such as BPS or BPF (Bisphenol S and F).
Research by University of Calgary professor Deborah Kurrasch has found that both BPA and BPS can cause alterations in brain development in fish that can lead to hyperactivity.
"I hope that people take a look at this study and really, really understand that we need to ban this chemical. BPA is not safe and every day the evidence is growing," MacDonald said.
With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip
