More than 15 million Americans—almost a third of them under the age of 18—suffer from asthma today, up from an estimated 6 million in 1980. Moreover, despite the advent of powerful new drugs, asthma-related deaths have almost doubled, from 2,891 in 1980 to 5,637 in 1995, the most recent year for which statistics are available. Perhaps most surprising, despite decades of research medical science has yet to find the root cause of the disease, much less a cure.
For the past 15 years, Dr. Fernando Martinez, director of the Respiratory Sciences Center at the University of Arizona in Tucson, has been following more than 1,200 children with the respiratory illness. He believes that an underlying weakness in some people's immune systems sensitizes them to allergens in their environment. "The presence of those allergens can trigger an asthmatic attack," explains Martinez, 48. He spoke to PEOPLE special correspondent Michael Haederle about this familiar yet baffling condition.
What exactly is asthma?
It's a very complex condition characterized by difficulty in breathing. The most important thing is, it comes and goes. It's chronic: Once you start having asthma, you have it for a long period of time.
Given all the research, why is so little known about asthma's cause?
Until recently our focus was on allergies and allergens and getting rid of allergens. We now believe what causes asthma is a more generalized reaction against many things, including infections and allergies.
What might be some of the causes?
Actually, asthma is many conditions including infection-associated asthma and allergy-related asthma, both probably due to various causes. But all share a common effect: Your chest gets tight and you start wheezing and coughing.
Who gets asthma?
People of any age, from babies to 90-year-olds. Most cases begin in the first few years of life. The onset is usually associated with a virus or a cold. People catch a cold and start to wheeze. While many children grow out of their symptoms, those whose relatives have asthma are much more likely to go on to have chronic asthma—one reason we think genes are involved.
How much has the incidence of asthma increased?
In Tucson we had between 50 and 80 percent more cases in 1990 than in 1970. In part this is because we have become more aware of asthma. But I think there's something real here—the increase is not just due to more diagnoses. And it is happening around the country, particularly among children. Since 1982 the rate of childhood asthma has increased 55 percent in the United States.
Why such a dramatic rise?
Something happens in the first three years of life that triggers this condition. It's a time when the immune system is adapting to the environment. One theory suggests that childhood infections help the immune system develop in a more robust way. That process may be necessary for the immune system to mature so that it can fight other infections in the future. It could be that our success at preventing childhood infections has left us more vulnerable to allergens in our environment.
Among what populations has asthma increased the most?
There are some striking comparisons between East and "West Germany that address this question. When the East collapsed, someone thought to start a comparison of asthma rates. Naturally they expected East Germany, with its severe air pollution, would have more asthma. What they actually found was the contrary. There was much more asthma in the West—more allergies too. In the U.S., African-Americans have more severe asthma than the rest of the population. They have at least a 50 percent higher prevalence of severe asthma than whites do. Higher severe asthma rates suggest that poverty and lack of access to preventive therapies may account for the differences between the two groups.
Is geography a factor?
The primary trigger for asthma attacks varies depending on where one lives. Inner-city residents are exposed to cockroaches and their feces. There is a protein in cockroach feces that is an antigen and can trigger an attack. Coastal residents are most susceptible to house-dust mites, whose feces become allergens when airborne, while in the Southwest mold spores are the usual culprit.
Is secondhand smoke a factor?
Lungs exposed to cigarette smoke in utero or postnatally develop abnormally. If lung function is lower, that may predispose children to asthma. We did a study several years ago showing that if antismoking laws were not enforced in day-care centers, there was a much higher incidence of asthma.
What about stress?
Stress does not cause asthma, but certainly it can cause symptoms. There is a subjective part to asthma that needs to be taken into account. There is a very active placebo response with asthma. Many people get better when they think they're receiving medication even when they're inhaling an inert substance.
Do cats and other pets cause asthma?
Cats have dander containing a very specific allergen that we inhale. Some people don't seem to be affected by their own cats but show symptoms when they visit someone else with a cat.
Can materials used in carpeting, furnishings and buildings make one asthmatic?
We don't know if these glues or, for example, formaldehyde, which is used in new furniture and water beds, cause asthma. We do know that for an established asthmatic, exposure to those substances is very bad.
Do well-insulated homes contribute to the increase in cases of asthma?
The hypothesis is that we're exposing people to more stuff when the air is sealed inside a home. But I'm not convinced that tighter houses are associated with an increase in asthma. For people whose asthma is triggered by allergens, very tight houses might be a factor. For those whose asthma is linked to respiratory infections, a tightly sealed house makes no difference. However, we can't find a general rule for asthma. That's the mystery of the disease.
Does air pollution increase the threat of asthma?
It's clear that air pollution is bad if you already have asthma. But if you don't have it, I'm not convinced that polluted air will give it to you. Some researchers believe that diesel emissions interact with allergens and make them more easily absorbed into the lungs. But asthma also develops in places where there is no diesel exposure and the environment seems pristine.
What is the correlation between the use of inhalers and asthma-related deaths?
When you have asthma that is not under control, inhalers may temporarily relieve your symptoms, but that is not enough. If you have severe asthma and use inhalers without anti-inflammatories, you are not controlling the basic cause of the disease. Not only do you mask your symptoms, but research has shown that the excessive use of inhalers may inhibit their ability to relieve symptoms in the future. That may put you at risk for death.
What works best to manage asthma?
The drugs we have available now include corticosteroids, cromones and antileukotrienes. We have very potent medicines that can be taken for a long time with few side effects. Today even people with quite severe asthma can engage in competitive sports, as do Olympic gold medalist Jackie Joyner-Kersee and retired NBA basketball player Dominique Wilkins.
Why is asthma hard to treat?
The problem is that you have to take the medicine all the time. It's very difficult to convince people to take medication when they are feeling fine.
How can you tell if your child is at risk, and what should you do?
Children who have eczema or constant runny noses seem to be most susceptible. A physician needs to get a good patient history from the parents. If we treat young asthma sufferers with the right anti-inflammatory drugs, we protect their lungs from the effects of chronic inflammation and prevent attacks when they are older. As a parent, first remember that 95 percent of the time asthma can be controlled and children can lead perfectly normal lives. Second, be very attentive. Inform the doctor immediately if there are certain alarm signals. If a child wakes up and has trouble breathing, that's a very important warning. It means the condition is getting worse. Many children don't want to admit they have symptoms, and then they can end up in an intensive care unit.
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