Exposure to bisphenol A (BPA) during the third trimester of pregnancy was inversely associated with adjusted risk for wheeze at age 5 years, but postnatal exposure was directly associated with risk, according to findings of a prospective birth cohort study published in the March issue of the Journal of Allergy and Clinical Immunology.
"Asthma prevalence has increased dramatically over the past 30 years, which suggests that some as-yet-undiscovered environmental exposures may be implicated," lead author Kathleen Donohue, MD, an assistant professor of medicine at Columbia University College of Physicians and Surgeons in New York City, said in a news release. "Our study indicates that one such exposure may be BPA."
Previous research suggests a link between BPA exposure and respiratory symptoms, obesity, impaired glucose tolerance, behavioral problems, and other health conditions. In July, the US Food and Drug Administration banned BPA in baby bottles and infant cups. Food can liners and store receipts remain common sources of BPA exposure.
The current study tested the hypothesis that BPA exposure during late fetal development and in the first few years of life would be associated with increased adjusted risk for wheeze and asthma in children. The researchers estimated BPA exposure from urinary BPA concentrations.
At the Columbia Center for Children's Environmental Health, 568 women in the third trimester underwent testing of total urinary BPA concentrations, as did their children at ages 3, 5, and 7 years. The investigators used online solid-phase extraction, high-performance liquid chromatography, and isotope-dilution tandem mass spectrometry to measure urine BPA concentrations. Questionnaires at ages 5, 6, and 7 years determined wheeze in the preceding 12 months, a physician examined children for asthma once between ages 5 and 12 years, and the children also underwent testing fraction of exhaled nitric oxide at ages 7 to 11 years.
After adjustment for secondhand smoke exposure and other asthma risk factors, postnatal BPA exposure was associated with about a 40% to 50% significantly increased risk for wheeze and asthma. Surprisingly, BPA exposure during the third trimester was inversely associated with risk for wheeze at age 5 years, in contrast to previous findings of a positive association between second-trimester BPA exposure and asthma risk.
"Like most other scientists studying BPA, we do not see a straightforward linear dose-response relationship," Dr. Donohue said, adding that heightened risk for wheeze and asthma occurred even at "fairly routine, low doses of exposure to BPA."
At ages 3, 5, and 7 years, more than 90% of children had detectable BPA metabolites, which is consistent with previous research. However, Dr. Donohue emphasized, even if the link is confirmed, not all children exposed to BPA will develop asthma, just as not all smokers will develop lung cancer.
BPA exposure was not linked to increased antibody levels to common airborne allergens, leaving the biological basis for the BPA-asthma association still undetermined.
Study limitations include the use of spot urinary BPA concentrations as a marker for BPA exposure.
The National Institute of Environmental Health Sciences currently recommends limiting BPA exposure by avoiding plastic containers numbers 3 and 7, reducing canned food consumption, and using glass, porcelain, or stainless steel containers rather than plastic, particularly for hot food and liquids.
"It is very important to have solid epidemiologic research like ours to give the regulators the best possible information on which to base their decisions about the safety of BPA," senior author Robin Whyatt, DrPH, professor of environmental health sciences and deputy director of the Columbia Center for Children's Environmental Health, said in the news release.
The National Institute of Environmental Health Sciences, US Environmental Protection Agency, John and Wendy Neu Family Foundation, Blanchette Hooker Rockefeller Fund, New York Community Trust, Educational Foundation of America, and Millstream Fund supported this study. Some of the study authors report various financial relationships with the National Institutes of Health, Columbia University, the Alpha-1 Foundation, the US Environmental Protection Agency, Indoor Biotechnology, and/or the National Institute of Environmental Health Sciences.
J Allergy Clin Immunol. 2013;131:736-742. Abstract
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Cite this: BPA Exposure Linked to Childhood Asthma Risk - Medscape - Mar 01, 2013.