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For the record

Does exposure to BPA during pregnancy affect aggressive behaviour in children?

Today’s papers report a study published in the journal Pediatrics which suggests that an increased level of exposure to Bisphenol-A (BPA) in pregnant women leads to an increase in the level of aggressive behaviour observed in their daughters. The study measured levels of BPA in the urine of 244 women at intervals during pregnancy and at birth, and of their children at yearly intervals until the age of three; at this point the women completed a survey on the behaviour of their children over this three-year period. Press coverage of the story included the Daily Mail, Independent, Telegraph and Reuters.

Here, Professor Richard Sharpe, University of Edinburgh/MRC Centre for Reproductive Health and Society for Endocrinology Special Interest Group on Endocrine Disruptors, explains the limitations of this research:

“The authors of this study cannot tell whether the reason for observed behavioural changes relate to BPA exposure or to diet. This is because around 95% of people’s BPA exposure is from what they eat and drink. Therefore, it is difficult in such ‘association studies’ to separate diet from BPA exposure. We know that diets containing higher levels of BPA tend to be less healthy (more canned and bottled products), and we know that diet can exert big developmental and behavioural effects, so diet is a huge potential confounding effect.

This study measured the level of BPA in urine samples to estimate exposure, but what this measures is inactive BPA. The best recent scientific evidence  - from feeding studies in human volunteers, where BPA was labelled and tracked through the body - shows that BPA is processed and excreted extremely rapidly, so that the amount that passes into the bloodstream in a biologically active form is so small that it cannot be measured. Studies measuring urinary BPA levels therefore do not tell us anything about the tissue (e.g. brain) exposure to BPA in the body, but this is likely to be tiny.”

The Daily Mail headline described BPA as a ‘gender-bending chemical’, however, Professor Sharpe said:

“The authors mention that BPA has intrinsic weak hormonal activity as an oestrogen and imply that this could cause behavioural changes in the girls. Much of this thinking is based on effects of oestrogens in rodent models that are not relevant to humans. In any case, at the miniscule levels of BPA exposure any oestrogen effect would be irrelevant.”

Document type: For The Record


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