NEW YORK, March 1 (UPI) -- U.S. researchers report a link between early childhood exposure to bisphenol A -- a chemical used in can liners and store receipts -- and higher asthma risk.

Lead author Dr. Kathleen Donohue, an assistant professor of Medicine at Columbia University College of Physicians and Surgeons and the Center for Children's Environmental Health, and colleagues tracked 568 women enrolled in the Mothers & Newborns study of environmental exposures.


BPA exposure was determined by measuring levels of a BPA metabolite in urine samples taken during the third trimester of pregnancy and in the children at ages 3, 5 and 7.

Physicians diagnosed asthma at ages 5 to 12 based on asthma symptoms, a pulmonary function test and medical history. A validated questionnaire was used to evaluate wheeze, Donohue said.

The study, published in the Journal of Allergy and Clinical Immunology, found after adjusting for secondhand smoke and other factors known to be associated with asthma, post-natal exposure to BPA was associated with increased risk of wheeze and asthma.

BPA exposure during the third trimester of pregnancy was inversely associated with risk of wheeze at age 5, the study found.

"Asthma prevalence has increased dramatically over the past 30 years, which suggests that some as-yet-undiscovered environmental exposures may be implicated," Donohue said in a statement. "Our study indicates that one such exposure may be BPA."