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Air Pollution Hurts Heart, Causes Asthma
Even 'Safe' Levels Linked to Disease
By Daniel DeNoon
Reviewed By Brunilda Nazario, MD
on Tuesday, November 11, 2003
WebMD Medical News
Nov. 11, 2003 -- Air pollution brings on heart and asthma attacks -- even at "safe" levels.
The findings come not from one but from three different studies. All link air pollution to death, disease, and/or injury.
'Safe' Air Pollution Harms Heart
Every increase in air pollution kills a few more people, find Demosthenes B. Panagiotakos, PhD, and colleagues at the University of Athens, Greece.
For every one-unit increase in carbon monoxide, the researchers suggest, there are two or more extra deaths each day.
"These health effects occur even at exposure levels below those stipulated in current air-quality standards," Panagiotakos says in a news release. "It is unclear whether a safe threshold exists."
Over a five-year period, the researchers collected daily values of various air pollutants in Athens. They also collected data on heart disease and strokes.
The main finding: A 10-unit increase in carbon monoxide ups heart and stroke deaths by 46%. Panagiotakos reported the findings at this week's Scientific Sessions 2003 meeting of the American Heart Association.
The results shouldn't be a big surprise. Similar studies in other cities reach similar conclusions.
A Drag on the Heart
For a person who smokes, even a short-term increase in air pollution could mean a heart attack.
Yves Cottin, MD, PhD, of the University of Dijon in Burgundy, France, and colleagues collected data on heart attacks that came on bad air days. Not everybody who got heart attacks on these days was a smoker. But pollution was more likely to trigger heart attacks in smokers than in non-smokers.
"Smokers are more sensitive to air pollution, as far as their risk for heart attacks," Cottin says in a news release. "This is yet another strong case against smoking."
It's also a warning for people already at risk of heart attacks to stay indoors and avoid strenuous exercise on bad air days, Cottin says.
Tiny particles floating in the air -- the kind of pollution mainly caused by diesel trucks -- were the worst offender. Even at levels below national standards, they increased the risk of heart attacks.
Cottin reported the findings at this week's Scientific Sessions 2003 meeting of the American Heart Association.
Asthma Attacks From Air Pollution
Mouse studies show that air pollution -- all by itself -- can trigger an asthma attack.
It used to be thought that dirty air alone was not enough to set off an asthma attack, but rather an allergen or other trigger such as pollen was needed to set off an attack. Not so, finds a research team led by Andre Nel, MD, PhD, of UCLA's David Geffen School of Medicine.
"This new experimental study shows that we need to pay closer attention to the intrinsic abilities of air pollutant particles to induce asthma," Nel says in a news release.
Nel's team first gave an allergen to mice to have them develop allergic asthma. This was followed in a few days by an aerosolized noseful of diesel particles. The mice immediately had an asthma attack. But a second study showed that mice bred to have airway trouble also got asthma from diesel particles -- even without the allergen.
For their next study, the researchers will look at actual particles collected from Los Angeles air.
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SOURCES: American Heart Association Scientific Sessions 2003, Orlando, Fla., Nov. 9-12, 2003
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Air Pollution hurts Heart, couses Asthma...