Dr. Roorda said his team was astonished to learn that many patients who were not being monitored continued to use drugs many years after the initial prescriptions had been written. Some patients used drugs prescribed for other family members. And some doctors renewed asthma prescriptions without first checking patients' lung condition.
The study also found that one-third of the group smoked cigarettes, despite the added risk for triggering asthma attacks.
"It is a very stupid situation," Dr. Roorda said.
The myth that most children outgrow asthma emerged in part from articles published in medical journals. Some studies reported that the prognosis for childhood asthma improved with puberty. Others suggested that two-thirds of children outgrow the disease. Yet a few studies said that up to 70 percent continue to have respiratory symptoms as young adults.
Experts now believe that the optimistic reports gave a false impression of asthma because they were incomplete, biased in the way patients were chosen for the studies and did not follow patients long enough to detect recurrences in the decades after adolescence.
"The second decade of life, between 10 and 20 years of age, is a relatively good period for most asthma patients," Dr. Roorda said.
As children mature, their airways grow larger, possibly easing the symptoms of asthma and creating the impression that the condition has disappeared, although the underlying inflammatory problem remains. In many cases, the children have moved away from home and from the agents, such as cats or dogs, that triggered their asthma.
"It is also the period of life when children grow out of their pediatrician instead of their asthma," Dr. Roorda said.
He went on: "Even when you have asthma symptoms, you can manage normal daily activities. So people may not realize that they have symptoms or become used to them. They find a way to cope with their disease and thus may think they have outgrown it, although they haven't. When you ask, 'How are you doing?' many say, 'Fine.' But when you specifically ask, 'do you suffer from breathlessness or wheezing or whatever?' then they say, 'Yes, I do.' But they do not realize that until the moment that you specifically ask them."
Dr. Albert L. Sheffer, an asthma expert at Harvard Medical School who headed the Government-appointed committee that wrote the new asthma guidelines in 1991, said that wider use of medical technology has helped experts understand that asthma usually persists. Newer tools like hand-held peak flow meters, which measure the amount of air exhaled, provide more objective measurements of an asthmatic's health, he said.
Doctors do not know how the newer therapies affect the long-term course of asthma and whether they prevent relapses and chronic lung damage.
To objectively determine the long-term benefits and hazards of such therapies on lung growth and development, the National Heart, Lung and Blood Institute has recruited 944 girls and boys ages 5 to 12 for its Childhood Asthma Management Program. It will be the first long-term study of the disease in children financed by the institute.
The program will follow the children at eight medical centers in the United States for at least five years at a cost of $45 million. It is aimed at resolving a medical debate: some doctors believe children with occasional symptoms from asthma benefit from daily medicine, while others believe these children should take medicine only when they are sick or have symptoms.
The study is to compare the effects of an inhaled corticosteroid called budesonide, a nonsteroidal inflammatory agent called nedocromil and a placebo. All children, including those receiving a placebo, will be able to inhale albuterol, a drug that relaxes the airways, as needed.
Researchers will determine the safety and adverse effects of each therapy and measure such factors as lung function, frequency of asthma attacks, use of health care resources, physical development and quality of life.
Reflecting on the progress in asthma therapy and the puzzles about its growing public health importance, Dr. Roorda said, "It is not as simple as was long thought."
Photo: "Outgrowing asthma is the exception to the rule," said Dr. Ruurd Van Roorda. He found that about 75 percent of children with moderate to severe asthma experienced breathing difficulties in their mid-20's. Dr. Roorda medicated an asthma patient at De Weezenlanden Hospital in Zwolle, the Netherlands. (Agence France-Presse for The New York Times) (pg. C3)