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Living
Near Busy Roadways Ups Chances Of Allergic Asthma
Medical News Today, Jan 18, 2011
An international team of lung experts has new evidence from a study in
shantytowns near Lima, Peru, that teens living immediately next to a busy
roadway have increased risk of allergies and asthma. Living next to a busy
highway makes the odds can go up by 30 percent for developing allergies to
dust mites, pet hairs and mold, and can double for having actual asthma
symptoms, such as wheezing and using medications to help them breathe.
The study, to be published in the Journal of Allergy and Clinical
Immunology online Jan. 18, is believed to be the first to link
heightened rates of allergic disease and exposure to traffic-related
pollution as a possible reason for increased rates of asthma along major
transit routes. Previous studies in Europe and North America relied on self
reports of asthma symptoms or produced conflicting results on possible
tie-ins with high levels of airborne pollution. Until now, experts say no
study has looked at how busy roadways affect the allergic origins of asthma,
a respiratory disease that afflicts some 17 million Americans, including
some 5 million children.
Experts at Johns Hopkins who participated in the study also found that the
risk of allergic disease, or atopy, and of having asthma among 725
teenagers, ages 13 through 15, was worst for those living immediately next
to the busy road, where a steady stream of traffic across multiple lanes
flowed unimpeded all day long. Atopy rates went up by 7 percent for every
city block (approximately 300 feet) closer they lived to the road. For those
who lived next to the road, the odds of having asthma were twice that of
those who lived a quarter-mile (about four city blocks) away.
"Our study clearly shows why we need to protect respiratory health and plan
future major roadways here or abroad away from residential areas and
schools," says senior study investigator and pulmonologist William Checkley,
M.D., Ph.D. "We can also now try preventive strategies aimed at reducing
allergic exposure near roadways to see if this lowers rates of asthma," adds
Checkley, an assistant professor at the Johns Hopkins University School of
Medicine and the University's Bloomberg School of Public Health.
Checkley and lead study investigator Lauren Baumann, M.H.S., chose a poor
district of Lima, called Pampas de San Juan de Miraflores, for their study
because Peru has the highest rates of asthma symptoms among children in
Latin America, at 26 percent. In addition, large numbers of shantytowns like
San Juan de Miraflores have sprung up around the nation's largest city
within the last few decades, many with a single, congested and slow-moving
main thoroughfare.
Baumann, a former Johns Hopkins graduate student in public health, says only
the most-at-risk children were included in the study, pointing out that
people who do not outgrow their asthma by their early teens are twice as
likely to remain asthmatic through adulthood. The year-long study, begun in
2008, included home visits to measure lung function and environmental air
pollutants.
"Family physicians and public health workers now know they need to more
closely monitor children who live near major roadways for allergies and for
the earliest signs of asthma," says Checkley, who notes that his team next
plans further studies on the underlying genetic profile of those at greater
risk of atopy and asthma. "Our ultimate goal is to identify other key
environmental stimuli or traffic-related pollutants that help trigger
allergic disease, and then use our knowledge of how they work biologically
to stop them before asthma sets in," he says.
Funding support for the study was provided by the Johns Hopkins Center for
Global Health; the U.S. National Heart, Lung and Blood Institute, and the
National Institute for Environmental Health Sciences, both members of the
National Institutes of Health (NIH); and the NIH-affiliated John E. Fogarty
International Center for Advanced Study in the Health Science.
Besides Checkley and Baumann, other Johns Hopkins researchers involved in
the study were Colin Robinson, B.A.; Robert Gilman, M.D.; Nadia Hansel,
M.D., M.P.H.; Robert Wise, M.D.; Patrick Breysse, Ph.D., M.H.S.; and
Kathleen Barnes, Ph.D. Other investigators included Juan Combe, M.D.;
Alfonso Gomez, M.D.; Karina Romero, M.D.; Lilia Cabrera, R.N., at A.B.
PRISMA in Lima; and Juan Hernandez, Ph.D., at the Instituto Nacional Salud
Publica in Cuernavaca, Mexico.
Source:
Johns Hopkins Medicine |
