Air pollution takes a toll on young lungs

http://www.msnbc.msn.com/id/33866693/ns/health-kids_and_parenting/

By Emily Sohn
updated 5:34 p.m. ET, Wed., Nov . 11, 2009

New parents already have plenty of potential hazards to worry about, from flame-retardants in footed pajamas to hormone-disruptors in breast milk. A new study now adds air to the list of environmental concerns.

Chronic exposure to air pollution, the study found, increases a baby's chance of developing bronchiolitis — a lung infection that is the most common cause of hospitalizations in the first year of life.

-----

That's true no matter where families live, she added. Her study, published in the American Journal of Respiratory and Critical Care Medicine, took place in the Pacific Northwest, which is known for its clean air and green living.

"This study adds to our understanding about infants and children as being susceptible to health risks from low-level, day-in, day-out exposure to contaminants," Karr said, "even in regions where we might not think it's a bad air pollution setting."

Bronchiolitis is an inflammation of small passages of the lungs. The condition peaks every fall and winter, and is most common in babies between 3 and 6 months old.

A virus called RSV is the most frequent cause of the infection, but the flu or other viruses can also trigger it.

While adults and most young children who catch RSV usually come down with cold symptoms for about a week, babies can develop complications from bronchiolitis. These include difficulty breathing, severe coughing and blue skin.

-----

In previous work, Karr had found a connection between air pollution and bronchiolitis in Los Angeles, which has some of the country's worst air quality. To follow up, she wondered how babies might be faring in supposedly "greener" places.

-----

Using maps of traffic density, industry and other pollution generators near where the infants lived, Karr and colleagues found that babies who had been exposed to the most air pollution, day after day, were between 5 and 10 percent more likely to be hospitalized for bronchiolitis than were babies exposed to the fewest air pollutants.

The biggest contributors were traffic, wood smoke and industrial sources. Exposure levels were all within recommended guidelines.

Pollutants can assault the immune system, cause inflammation and disturb a barrier of cells in the lungs that normally keep out respiratory viruses, Karr said. But there might be other explanations for her findings, too.

At the Columbia Center for Children's Environmental Health in New York, researchers have been putting air-monitoring backpacks on pregnant women and following their babies through adolescence. The results of that study suggest that urban air pollution is affecting the expression of genes in fetuses, setting kids up to develop asthma later in life.

-----