Study finds link between BPA and asthma

The list of products containing bisphenol A is pretty long: it coats the inside of the food cans; it can be found in certain plastic containers; it is sometimes found on cash register receipts.

And the list of maladies linked to the chemical is growing longer.

The latest study, by researchers at the Columbia Center for Children's Environmental Health , suggests a possible connection between BPA detected in urine samples of children and later problems with breathing.

The study

A group of 568 mothers and their children had urine samples taken - the mothers during the third trimester of pregnancy and the children at different intervals after they were born. The samples were then tested for BPA. Researchers found what can, at best, be described as a group of positive associations (not cause and effect) between BPA and breathing problems.

The results

A child's chances of suffering with asthma were increased if BPA was detected in their urine samples at ages 3, 5 and 7. In addition, when BPA was measured in urine at age 3, the chances of wheezing by ages 5 and 6 were increased. Same thing for 7-year-olds: BPA meant later problems with wheezing.

An exception to the findings occurred among children with BPA measured in their urine at 5 years of age; those children did not have problems with wheezing during follow-ups one or two years later.

"What is important is that we were seeing the association at routine low doses of exposure," said Dr. Kathleen Donohue , the lead study author.

Caveats

One anomalous finding in the study, published Friday in the Journal of Allergy and Clinical Immunology : If BPA was detected in a mother's urine during her third trimester of pregnancy, there was less likelihood that her child would have breathing problems at age five - the opposite of what researchers expected.

That finding also contradicts data, presented two years ago by the Penn State College of Medicine, suggesting that high BPA levels found during the 16th week of pregnancy are associated with an increased risk of wheezing in children until age three. (One key difference between the two studies is that urine samples were taken from the pregnant women during different trimesters.)

Takeaway

The whole relationship between BPA - which is believed to be present in almost everyone in the United States because the chemical is in so many products - and ill health is a subject of debate.

On one hand there is a community of researchers finding associations between the chemical and things like childhood obesity and behavior problems . On the other are industry groups that routinely question the methodology and viability of these studies.

Somewhere in the middle are government agencies, which consider BPA to be a product of concern, but stop short of calling it dangerous.

So this latest study suggests another layer of understanding about the possible health effects of BPA, but it is far from definitive. The best that this, or any other study, can offer is a possibility.

Donohue believes that this data will be strengthened by similar studies. Then there might be a firmer ground on which to prop these findings. Until then, she reiterates that the study suggests, "an association, not causation. But it does suggest that BPA may increase asthma."