FRIDAY, Dec. 5, 2003 (HealthDayNews) -- New research from Finland suggests people who live or work around tobacco smoke may be two to five times more likely to suffer from asthma.
But experts caution the findings don't necessarily mean that otherwise healthy people will develop asthma because they hang around smokers.
The research "doesn't say that tobacco smoke would cause asthma in someone who had no other high risk," says Dr. William E. Berger, a California allergist and author of the book "Allergies & Asthma for Dummies."
An estimated 17 million Americans -- including almost 5 million children -- have asthma, a condition that causes inflammation in the lung's airways, leading to wheezing and coughing.
"The immune system is overreacting to environmental allergens and producing a response, which could be healthy under other circumstances, but in these circumstances it is unhealthy and unprotective," says Dr. Norman H. Edelman, a consultant for scientific affairs at the American Lung Association.
In the Finnish study, researchers looked at 521 people, aged 21 to 63, who developed asthma over a 2.5-year period. They compared them to 932 healthy people.
The findings appear in the December issue of the American Journal of Public Health.
People who were regularly exposed to tobacco smoke at work were 2.2 times more likely to develop asthma, while those exposed at home were 4.8 times more likely to become ill.
It's well-known that smoke can exacerbate asthma by simply acting as a lung irritant, Edelman says. "Certainly for people who smoke, the smoking makes their asthma worse. There's no doubt about that. And there's increasing evidence that exposure to smoking can cause an asthma attack," he says.
Many people appear to be susceptible to asthma, but it only appears in their lives when they go near substances that trigger reactions, Berger explains.
He uses the example of his father, who only started suffering from allergies after arriving in the United States from Europe and being exposed to high levels of ragweed: "He had a genetic predisposition to develop hay fever, and all it took was the right exposure or right trigger," Berger says.
For now, there are still questions about whether smoking can trigger asthma in people without a predisposition. "That's a very hard thing to sort out," Edelman says.
But one thing remains clear: People, especially children, shouldn't be around smoke.
"We at the lung association feel that the critical issue is smoking cessation," Edelman says. "It's inconceivable to me that someone would expose someone to cigarette smoke. If they're hooked, they could go outside to smoke. To continue to smoke and buy an air purifier and think you're protecting your child is bad parenting."
More information
To learn more about allergies and asthma, visit the American Academy of Allergy, Asthma and Immunology or the National Institute of Allergy and Infectious Diseases.
