The research by Braun et al., ‘Impact of Early Life Bisphenol A Exposure on Behaviour and Executive Function in Children’, is due to be published online today in the November issue of Pediatrics.
The joint team comprised researchers from the Harvard School of Public Health (HSPH), Simon Fraser University in Vancouver and Cincinnati Children’s Hospital and Medical Centre.
Using data from a birth cohort of 244 mothers and their 3-year-old children in the Cincinnati area, the scientists examined the relationship between BPA concentrations and child behaviour.
Mothers gave 3 urine samples during pregnancy and at birth that were tested for BPA, their offspring were tested each year between the ages of 1-3, while mothers completed surveys of child behaviour at age 3.
‘Aggressive, anxious and depressed...’
Braun et al. found BPA in over 85 per cent of the urine samples from mothers and over 97 per cent of those from children, and although child BPA levels fell between the ages of 1 to 3, the team found that they were higher and more variable than those of mothers.
Assessing the study findings, lead author Joe Braun said: “None of the children had clinically abnormal behaviour, but some children had more behaviour problems than others.
After addressing possible contributing factors, the team linked increasing gestational BPA concentrations with more hyperactive, aggressive, anxious and depressed behaviour, as well as poorer emotional control and inhibition in girls, but this relationship was not seen in boys.
Braun cited two prior studies suggesting that exposure to BPA in the womb affects child behaviour, but said the new study was the first to show that in utero exposure to the chemical was more important than childhood exposure.
"Gestational, but not childhood BPA exposures, may impact neurobehavioral function, and girls appear to be more sensitive to BPA than boys," Braun said.
Braun et al. said that more research was needed to fully understand the health effects of BPA, but that health practitioners were able to advise consumers about reducing exposure levels.
“Clinicians may advise concerned patients to reduce their exposure to certain consumer products, but the benefits of such reductions are unclear,” the scientists wrote.
Clinical relevance unclear, ACC
But Steven Hentges, from the ACC’s Polycarbonate/BPA global group said that Braun et al.'s work showed "significant shortcomings in study design".
“For parents, the most important information from this report is that the authors themselves question its relevance – the clinical relevance of these findings is unclear at this point," he added.
The ACC believed the research conclusions were of “unknown relevance to public health”, Hentges said, adding that the researchers had themselves acknowledged statistical deficiencies, including a small sample size and the possibility of ascribing results to chance.
Calling for information for parents and consumers on “actual, real world safety” the ACC said that recent EPA-funded research conducted by the Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC) and Pacific Northwest National Laboratory did not support the new study’s findings.
This second study, by Teeguarden et al. indicated that because of the way BPA is processed in the body, it is very unlikely that it could cause health effects at any realistic exposure level.
Hentges added: “Furthermore, regulators from Europe to Japan to the US have recently reviewed hundreds of studies on BPA and repeatedly supported the continued safe use of BPA."
North American Metal Packaging Alliance (NAMPA) chairman Dr John Rost also noted the unclear clinical relevance of the findings, and said they could be based upon "chance, socio-economic factors or other chemical compounds".
In addition, Rost criticised the study design and what he said was the scant relevance of the spot urine analysis undertaken "at a few, intermittent times - six over the course of 4 years in this study".
He said: "BPA is so quickly and efficiently metabolised from the body that one-time spot analysis only tells what you were exposed to over the last few hours.
"When compared to a nine-month gestation period, the samples taken by the study reveal little about total exposure, for mother or fetus, throughout the pregnancy," Rost added.
Title: ‘Impact of Early Life Bisphenol A Exposure on Behaviour and Executive Function in Children’
Source: Pediatrics, November 2011: 128(5)
Authors: J.Braun, A.Kalkbrenner, A.Calafat, K.Yolton, X.Ye, K.N Dietrich, B.P Lanphear.