Living near busy roads is tied to kids' lung risk
A health official calls the study 'a pretty significant finding.'
By CHRIS BOWMAN
Growing up near a freeway stunts a child's breathing capacity for a lifetime, significantly increasing the risk of serious lung and heart diseases later in life, according to researchers who monitored thousands of Southern California children for up to eight years.
The landmark study, led by a team of University of Southern California scientists and released Thursday, delivers a sobering answer to a long-standing question about the health effects of being raised near a busy roadway where air is chronically polluted. These children not only are more likely to develop asthma, but their lung development can be permanently cut short, increasing their odds of having a heart attack or a life-threatening respiratory condition, starting as early as their 50s.
"It's a big risk factor," said James Gauderman, the author and principal investigator of the study by researchers at USC's Keck School of Medicine.
"If you've got less lung capacity, and you get hit with the flu or pneumonia, you've got less reserve to fall back on," Gauderman said.
What air regulators said
The findings carry profound policy implications nationwide for agencies that monitor and regulate air pollution, for locally elected officials who determine where to place new roads and housing tracts, and for education officials who buy property for new schools, California air quality regulators said.
"This is a pretty significant finding. It strengthens the information we need for some of our control programs," said Richard Bode, chief of the health and exposure branch of the state Air Resources Board.
Earlier studies measuring the environmental fallout on neighbors of Southern California freeways prompted the state regulators to go beyond their traditional scope of regional air quality and begin examining local "hot spots."
In the past six years, studies have focused on predominantly low-income neighborhoods near heavy industry, ports, railyards and at schools on busy roads.
The USC study draws data from the state-funded Children's Health Study, a long-term investigation of respiratory health that has been tracking thousands of schoolchildren since 1993. The children, now in their 20s, lived in 12 Southern California communities, from the relatively clean towns of Lompoc and Santa Maria in Santa Barbara County to smoggier Long Beach and Riverside.
Largest of its kind
The project is the largest air pollution health effects study ever undertaken, Gauderman said
While earlier findings from the children's project were more applicable to urban Southern California, results of the new freeways study should resonate nationwide, Gauderman said.
Even in communities with overall good air quality, Gauderman said, "If children are living near a busy road, then our results suggest that they are at increased risk for these kinds of health effects."
The study, scheduled to be published Feb. 17 in the Lancet medical journal, correlated the data from community air quality samples and annual lung function tests with the locations of the children's homes, relative to freeways and other busy roadways.
More than 3,600 children participated for up to eight years. Investigators examined the link between their exposure to traffic pollution at home and their lung development, measured by how much air the child could forcefully exhale into a device called a spirometer.
The researcher accounted for factors that could skew results such as socioeconomic status, smoking and breathing disorders such as asthma.
They found that the overall lung capacity of children living within a mile from a freeway was 3 percent below normal.
The performance of their tiniest airways, where oxygen is delivered to the bloodstream, was about 7 percent below normal.
The reduced breathing capacity is unnoticeable among children because their lungs are still growing. Even after the lungs stop developing, about age 18, the deficit appears to have no effect because their lung capacity, which has lots of reserve, is at its peak.
Lung capacity declines naturally with age, beginning in the 30s and 40s. For those with lungs already compromised by air pollution, the deficit is all the greater.
"These individuals start off living with reduced lung function, so that when they reach middle age, they could be at greater risk for respiratory and cardiovascular disease," Gauderman said. "Most people expect to be active in the 50s."
Earlier research in the children's health project indicated that moving to cleaner environments could improve children's breathing.