London: Prenatal exposure to bisphenol A (BPA) may have negative effects on respiratory health in school-age girls, warns a study.

Bisphenols are chemical substances used in the manufacture of plastics and resins found in many consumer products, such as food cans, reusable bottles and toys.

The most well-known is BPA, a known endocrine disruptor used widely in the manufacture of food containers and the interior coatings of such recipients.

It is already known that bisphenols are present in maternal milk and that they can cross the placental barrier.

The new study, published in the journal Environment International, revealed an association in girls between concentrations of BPA in maternal urine during pregnancy and an increased risk of asthma and wheezing at school age.

A two-fold increase in the concentration of BPA was linked to a 13 per cent higher risk of respiratory symptoms.

This association was not, however, observed in boys or in the case of the other two bisphenols studied. Neither were any associations observed between prenatal BPA exposure and lung function at school age.

"Our results are in line with those of earlier studies, which have also reported that bisphenol A has a negative impact on respiratory health in childhood," said Alicia Abellan, from Barcelona Institute for Global Health (ISGlobal) in Spain.

"We believe that the effect may be due the fact that bisphenols can cross the placental barrier and interfere with the child's respiratory and immune systems during the developmental phase," she explained.

The team analysed data from more than 3,000 mother-child pairs from six European countries - Spain, France, Greece, Norway, the Netherlands and the UK - collected between 1999 and 2010.

High prevalence of BPA as found in 90 per cent of the samples.

"Bisphenols are endocrine disruptors and can interfere with sex hormones. As our findings suggest, this may give rise to differences in the effects they have depending on the sex of the person exposed," said Maribel Casas, ISGlobal researcher.

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