Corporate Banner
Satellite Banner
Environmental Analysis
Scientific Community
Become a Member | Sign in
Home>News>This Article

Early-life Air Pollution Linked with Childhood Asthma in Minorities, in Study

Published: Thursday, June 20, 2013
Last Updated: Thursday, June 20, 2013
Bookmark and Share
Research by UCSF team indicates that traffic-related pollution might be a cause.

A research team led by UC San Francisco scientists has found that exposure in infancy to nitrogen dioxide (NO2), a component of motor vehicle air pollution, is strongly linked with later development of childhood asthma among African Americans and Latinos.

The researchers said their findings indicate that air pollution might, in fact, be a cause of the disease, and they called for a tightening of U.S government standards for annual exposure to NO2.

The study is reported online currently in the American Journal of Respiratory and Critical Care Medicine ahead of print publication.

In the study, the largest to date of air pollution exposure and asthma risk in minority children in the United States, the team found that for every five parts per billion increase in NO2 exposure during the first year of life, there was a 17 percent increase in the risk of developing asthma later in life.

The study involved 3,343 Latino and 977 African American participants.

“Many previous studies have shown an obvious link between traffic-related pollution and childhood asthma, but this has never been thoroughly looked at before in an all-minority population,” said lead author Katherine K. Nishimura, MPH, a graduate student in the laboratory of senior author Esteban G. Burchard, MD, MPH, a UCSF professor of bioengineering and therapeutic sciences and medicine and director of the UCSF Center for Genes, Environment & Health.

Minorities tend to live in areas of higher air pollution and have a higher risk of developing asthma, the researchers said.

What made the current study different from previous research, said Nishimura, was that the scientists looked retrospectively at the study participants’ exposure to air pollution in early childhood, before they developed asthma. Children who developed asthma before this exposure period were excluded.

“Any participant with asthma in this study was exposed to air pollution in infancy, before they developed the disease, which is a step in the right direction in inferring causality,” said Nishimura.

“This work adds to the growing body of evidence that traffic-related pollutants may be causally related to childhood asthma,” said Burchard.

National Standard for NO2 is 'Too Lax'

Study co-author John R. Balmes, MD, of UCSF and UC Berkeley, pointed out that a previous study of children living in Southern California showed that living and attending school close to major roadways was associated with an increased risk of new-onset asthma. “Together with our findings, this makes for strong evidence that reducing children’s exposure to traffic emissions can prevent some cases of asthma,” said Balmes.

One immediate implication of the study, said Burchard, is that the national standard for NO2 set by the Environmental Protection Agency is “too lax by far.” He noted that the current EPA annual standard is 53 parts per billion (ppb), while the study subjects were exposed, on average, to 19 ppb during the first year of life.

“Children growing up in Southern California have been shown to have reduced growth of lung function when annual NO2 levels are below the current national annual standard,” added Balmes.

The participants, who were between the ages of 8 and 21 and had no other lung diseases or chronic illnesses, were recruited from study centers in Chicago, New York City, Houston, the San Francisco Bay Area and Puerto Rico. To adjust for instances when study participants moved residences, air pollution exposure for all subjects was assessed by using the residential histories from birth through time of recruitment. The researchers based their air pollution exposure estimates on EPA annual measurements.

“The geographic diversity of the study population strengthens the results, because the effects we see are consistent across a wide range of urban environments and conditions,” said Nishimura.

Possible Explanations for How Air Pollution Causes Asthma

While the study was not designed to investigate how air pollution might cause childhood asthma, said Nishimura, the investigators are looking at two possible causes.

The first is that NO2 can interact with a number of other pollutants to create reactive oxygen species – chemically reactive molecules containing oxygen – which can, in turn, damage developing lungs. Immune systems that develop under such conditions, she said, could be “trained” to respond to pollutants as triggers that could later induce asthma.

Another possible explanation, said Nishimura, is that pollutants can potentially cause a genetic predisposition to asthma by altering methylation patterns in DNA. Methylation is a chemical change that alters gene expression without affecting the underlying structure of the DNA itself.

“It has been shown that changes in methylation, which can be affected by pollution, tobacco smoke and even stress, can be inherited across multiple generations,” said Burchard. “Our group is currently investigating methylation as the possible outcome of exposures to a number of pollutants.”

Burchard cautioned that air pollution is “not the entire story,” noting that despite its low air pollution levels, Puerto Rico has the highest asthma prevalence and morbidity in the United States. “This is intriguing, and leaves us more work to do,” he said.

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,800+ scientific posters on ePosters
  • More than 4,000+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Scientific News
Safer, Faster Way To Remove Pollutants From Water
Using nanoparticles filled with enzymes proves more effective than current methods.
Low Impact Fracking Fluid on Top at IChemE Global Awards
A novel fracturing fluid designed to make fracking greener.
Marine Invasive Species May Benefit From Rising CO2 Levels
Ocean acidification may well be helping invasive species of algae, jellyfish, crabs and shellfish to move to new areas of the planet with damaging consequences, according to the findings of a new report.
Game for Climate Adaptation
MIT-led project shows a new method to help communities manage climate risks.
Tufts Chemist Discovers Way to Isolate Single-crystal Ice Surfaces
Promises insights into climate, environment and age-old riddles, such as why no two snowflakes are alike.
Potential Indirect Effects of Humans on Water Quality
Newly studied class of water contaminants occur naturally, but are more prevalent in populated areas.
Rapid Method for Water, Air and Soil Pathogen Screening
Researchers at BGU and the Massachusetts Institute of Technology (MIT) have developed a highly sensitive, cost-effective technology for rapid bacterial pathogen screening of air, soil, water, and agricultural produce in as little as 24 hours.
First Results Describing Sick Sea Star Immune Response
Though millions of sea stars along the West Coast have perished in the past several years from an apparent wasting disease, scientists still don’t know why.
Microbe Sleuth
Tanja Bosak examines how life and the Earth evolved in tandem during their early history together.
The Age of Humans Controlling Microbes
Engineered bacteria could soon be used to detect environmental toxins, treat diseases, and sustainably produce chemicals and fuels.
Scroll Up
Scroll Down

Skyscraper Banner
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,800+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,000+ scientific videos