Phthalates heighten risk for childhood asthma

Researchers at the Columbia Center for Children's Environmental Health at the Mailman School of Public Health are the first to demonstrate an association between childhood asthma and prenatal exposure to two phthalates used in a diverse array of household products. Results appear online in the journal Environmental Health Perspectives.

Children born to mothers exposed during pregnancy to higher levels of the chemicals, butylbenzyl phthalate (BBzP) and di-n-butyl phthalate (DnBP) had a 72 percent and 78 percent increase in risk of developing asthma between age 5 and 11, respectively, compared with children of mothers with lower levels of exposure, the researchers found.

"Everyone from parents to policymakers is concerned by the steep rise in the number of children who develop asthma. Our goal is to try and uncover causes of this epidemic so we can better protect young children from this debilitating condition," says first author Robin Whyatt, DrPH, professor of Environmental Health Sciences and co-deputy director of the Columbia Center for Children's Environmental Health at the Mailman School.

"Our study presents evidence that these two phthalates are among a range of known risk factors for asthma," adds Dr. Whyatt. Other risk factors include tobacco smoke, air pollution, obesity, and a history of allergies.

Phthalates are used in everything from synthetic fragrances to plastic food containers, vinyl flooring, insect repellent, shower curtains, even steering wheels and dashboards ("new car smell" contains phthalates). Since 2009, several phthalates- including BBzP and DnBP- have been banned from children's toys and other childcare articles in the United States. However, no steps have been taken to protect the developing fetus by alerting pregnant women to potential exposures. In the U.S., phthalates are rarely listed as ingredients on products in which they are used.

"The fetus is extremely vulnerable during pregnancy. While it is incumbent on mothers to do everything they can to protect their child, they are virtually helpless when it comes to phthalates like BBzP and DnBP that are unavoidable. If we want to protect children, we have to protect pregnant women," says the study's senior author Rachel Miller, MD, professor of Medicine (in Pediatrics) and Environmental Health Sciences; and chief of Pediatric Allergy, Immunology, and Rheumatology at Columbia University Medical Center; and co-deputy director of the Columbia Center for Children's Environmental Health at Columbia's Mailman School of Public Health.

What is asthma in children?

Asthma is a chronic inflammatory disorder of the airways, characterized by recurrent, reversible, airway obstruction. Airway inflammation leads to airway hyperreactivity, which causes the airways to narrow in response to various stimuli, including allergens, exercise, and cold air.

How common is asthma in children?