Prenatal exposure to phthalates raises risk of childhood asthma
A team of scientists from the Columbia Center for Children's Environmental Health at the Mailman School of Public Health at Columbia University released a new study linking prenatal exposure to phthalates to a heightened risk of childhood asthma. The paper, published in the journal Environmental Health Perspectives, adds to the growing list of potential health problems tied to exposure to these chemical compounds during pregnancy.
"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," Robin Whyatt, DrPH, first author of the study, said in a statement.
Developing babies are unprotected
Phthalates are virtually ubiquitous, found in items such as shower curtains, car dashboards, vinyl flooring, insect repellant and even plastic food containers. According to the U.S. National Library of Medicine, phthalates are also present in detergents and cosmetics. Previously, phthalates were found in children's toys, but after past research showed that exposure to phthalates could cause problems in the reproductive system, and that some of these compounds are actually carcinogenic, American toy manufacturers banned their use from production to protect children. However, less is known about whether phthalates can impact on the developing foetus.
The authors of the new study had previously shown that prenatal exposure to certain phthalates can raise the risk of eczema, while childhood exposure to bisphenol A may lead to asthma. To investigate whether prenatal exposure to phthalates can lead to childhood asthma, the researchers enrolled 300 pregnant women into their study. All subjects provided urine samples during their third trimester, as did the children they eventually gave birth to. The pediatric samples were collected when the subjects were 3, 5 and 7 years of age. The aim was to measure levels of metabolites associated with phthalates, and measure the prevalence of asthma among children ages 5 to 11 years.
Results showed that the highest levels of exposure to butylbenzyl phthalate (BBzP) and di-n-butyl phthalate (DnBP) were linked to risk increases for childhood asthma of 72 percent and 78 percent, respectively. However, there were no such relationships found for di-2-ethylhexyl phthalate (DEHP) and diethyl phthalate (DEP).
Although the researchers linked prenatal exposure to phthalates to childhood asthma, they could not determine what products or activities were associated with the greatest level of exposure, or how these chemical compounds drove the development of the disease. They speculated that the mechanism of action is inflammation and oxidative stress.
What is the asthma burden in the U.S.?
The American Lung Association estimated that nearly 27 million people in the U.S., including 7 million children, are living with asthma. According to the organization, asthma is likely attributable to a combination of factors, including genetics, allergies and respiratory infections during early childhood. Although the characteristic asthma flares that make it difficult to breathe are treatable with medication, health experts emphasize the importance of avoiding the irritants that trigger such flares, including smoke, car exhaust, dust, fragrances, and workplace and household chemicals.
(Author: Christopher Boyd, Chem Service Inc October 2014)
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