Lots of funky stuff -- roach parts, dust mites, even ragweed pollen -- can trigger asthma attacks. But other things can also cause the airways to constrict:
Drugs and food: As many as 20 percent of adult asthmatics have attacks after exposure to aspirin, non-steroidal anti-inflammatory medicines, or sulfites in food and drink.
Exercise: An estimated 85 percent of allergic asthmatics wheeze after exercise, with long-distance running and serious cycling being the worst offenders. (Swimming seems particularly benign to asthmatics.)
Emotions: Stress and fatigue can affect the immune system in ways that start or exacerbate an attack. "Any chronic disease," says Marcus Cohen, an allergist in private practice in Madison, Wis., "is precipitated and made worse by psychosomatic factors."
Violence: A study by Rosalind Wright of Brigham and Women's Hospital in Boston suggests that children exposed to violence in their neighborhoods (through hearing gunshots or witnessing physical violence) were twice as likely as other children to experience wheezing and to use emergency medicine to dilate their bronchial tubes. "Researchers have been studying the psychological impact of violence on children, but we also need to be looking at the impact of violence on physical disease," Wright said.
Here's more detail on these triggers -- revolting and otherwise.
An industrial disease?
Edelman agrees that indoor air pollution is a factor, pointing out that people are spending more time inside. There are dust mites, smoke and mold in houses that are closed for energy efficiency. And kids are spending more time in day care, and are getting more viral infections, which predispose them to asthma."
Outdoor air pollution is also an important cause of asthma, he says, "but it's hard to attribute the increase to that, since it's not been increasing for the last 10 years. At the same time, he adds, the Lung Association says the relationship between asthma and air pollution -- particularly fine particles and ground-level ozone -- is clear enough to require federal passage of the proposed air pollution standards. Air that meets the current EPA standards "precipitate asthma attacks," he states.
To some experts, this laundry list of triggers point to the general condition of living in an industrial society as the overarching cause of asthma. "We live in houses that are closed, work in businesses that are closed, the windows don't open, and any pollutant is recirculated," says Cohen. "There's a tremendous amount of volatile organic compounds from synthetic carpet and vinyl upholstery that are off-gassing all the time. Almost everything is carpeted, and that's a place for dust mites to multiply." And many energy-efficient houses have moisture problems that promote the growth of mold and mites. "There are a lot of things going on," Cohen concludes.
Deadly statistics
Overall death and hospitalization rates rise in lockstep with air pollution levels. For example, an increase in airborne fine particles of 100 micrograms per cubic meter increased the death rate by 13 percent in Sao Paolo, Brazil (see "Air Pollution and Mortality..." in the bibliography). Breathing nitrogen oxide, a key component in auto exhaust, exacerbates the lung's allergic reaction to dust mites. The Why Files covered the air pollution standards dispute.
So exactly what is causing the increase in asthma? "The honest answer is that we don't know" the full story, Edelman concludes. "Speaking for the American Lung Association, I'd say it's urgent that we find out what the true cause is."
Right or wrong:
With each 10 microgram increase in airborne fine particles, reports of asthma attacks go up by 3 percent, according to Douglas Dockery of the Harvard School of Public Health (see "Mounting Evidence Ties Asthma to Car Fumes" in the bibliography).
