Infants and very young children in Tucson exposed to high levels of vehicle diesel pollution are more likely than other kids to suffer from early childhood wheezing, a potential asthma indicator.
That's the finding of a new University of Arizona study, the first in Tucson to link vehicle air pollution to respiratory problems in children.
Based on a study of 700 people, it found a connection between the diesel exposures and what's known as "transient wheezing," which starts in infancy and goes away at about age 5 or 6, said Paloma Beamer, an assistant UA professor of environmental health sciences and a principal investigator and one of six researchers on the study.
The study compared children from census tracts with the highest diesel emissions, including areas along Interstates 10 and 19 and the Aviation Parkway, with kids in the entire metro area. The researchers got the diesel data from the Environmental Protection Agency. The main sources of the diesel emissions were trucks, buses and trains.
The study found that children with higher diesel exposure were 1 1/2 times more likely than other kids to have a respiratory illness that included wheezing in their first three years of life. They were nearly twice as likely to have transient wheezing in early childhood that went away by age 6, Beamer said.
In short, young kids who wheeze "are more likely to have diesel exposure than those who don't wheeze," said a second UA researcher who worked on the study, Anne Wright, a professor of pediatrics.
Wright is also a founder and a co-principal investigator of a much broader research effort known as the Tucson Children's Respiratory Study from which the kids studied in the wheezing research were drawn. The larger respiratory study has monitored the health of a target group of Tucsonans since they were newborns back in 1980.
Wheezing is a constriction in the lungs that sounds like whistling and makes it hard for air to move in and out of the lungs. A majority of children have wheezing problems in the first few years of their lives due to viral infections, but for most of them it goes away later, Wright said.
Later in life, wheezing is more common among allergy sufferers and is a leading symptom of asthma for older people. For younger kids, wheezing patterns are more complicated, Wright said. A lot of kids who get asthma later in life will wheeze in their early years, but most kids who wheeze in their early years do not go on to have asthma, she said.
The association between diesel exhaust exposure and transient wheezing was stronger in kids whose parents don't smoke, Beamer said. With kids of smokers, the smoking is a much bigger factor than the diesel emissions affecting the kids' respiratory health.
Kids of mothers without at least a high school diploma also had a higher chance of being affected by the diesel particulate emissions, she said.
"Those households may already be under other types of socio-economic stress," Beamer said.
Numerous university studies in the Los Angeles area have in the past decade linked a variety of health problems to living near and breathing fumes from freeways. They include respiratory ailments, autism, premature births and hardening of the arteries.
But Beamer said that as far as Tucson goes, it is too early to say whether people with kids or who expect to have kids should avoid living near freeways.
"Is this something that deserves more inspection? Yes," Beamer said. "But I would be far more concerned about a smoker living in my household than living close to the freeway."
The researchers' long-term goal is to find ways for parents to intervene at the home level to protect their kids if they live in a neighborhood near a freeway, she said.
"If you are a mother living near the freeway for a reason, are there things you can do to prevent childhood exposures during critical periods of development?"
The researchers are also going to see if any kinds of public policies need changing to protect such children.
The preliminary study, which has not yet been published, was funded with a $40,000 grant from the UA's Southwest Environmental Health Sciences Center.
Beamer and her colleagues have recently started a much more expansive, $670,000 project to try to determine if a relationship exists between exposures to diesel pollutants in the Tucson area and lung and immune-system development and allergies. The National Institutes of Health is financing this ongoing study.
Contact reporter Tony Davis at tdavis@azstarnet.com or 806-7746.
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