TUESDAY, Aug. 10, 2004 (HealthDayNews) -- In bad news for children with asthma, a new study suggests that as many as 20 percent of them will see their lungs lose strength over a five-year period.
The kids may not notice the difference, and researchers aren't sure exactly what the decline in lung function will mean for their future health. But the study's senior author said the findings provide more evidence that doctors must closely monitor children with asthma.
"This is an important part of the disease that we're now learning to appreciate and follow," said Dr. Stanley Szefler, head of pediatric clinical pharmacology at the National Jewish Medical & Research Center. "It may have significant effects on long-term outcomes."
About 10 percent of children and 15 percent of adults have asthma. While doctors used to think it was caused by spasms in the lungs, they now suspect it's caused by inflammation due to an overactive immune system, Szefler said.
The typical symptoms of asthma are wheezing and shortness of breath. "Asthmatics tend to be able to get air in, but have difficulty getting air out, which causes air trapping and lung expansion," Szefler said. "It's like a balloon that can't let air out, but gets more in."
About 5,000 people die from asthma each year, about a third of whom are children, Szefler said. For some reason, kids with asthma are less likely than adults to seek medical care when they're severely ill, said Dr. Sean Deitch, an emergency medicine physician at Scripps Memorial Hospital in San Diego. "Children will be reluctant to bring up symptoms to parents, and parents will try to stay at home and self-treat them."
In the new study, Szefler and colleagues examined the medical records of 990 American children with mild to moderate asthma who were studied for about five years. The children, who came from various parts of the United States, were about 8 years old when the study began in the early 1990s. The participants, who are now around 18, continue to take part in the study.
All the children received albuterol, a common asthma medication. Some received one of two inhaled anti-inflammatory drugs -- budesonide and nedocromil -- or a placebo that provided no medical benefit.
Doctors regularly measured the effectiveness of their lungs by having them blow into a measuring device that's similar to the Breathalyzers used by law enforcement.
The findings appear in the August issue of the American Journal of Respiratory and Critical Care Medicine.
About 20 percent of the children lost more than 1 percent each year of the normal lung capacity they should have had. Their lungs declined no matter whether they had mild or moderate asthma or whether they took one of the steroid drugs or a placebo. Boys were more likely to suffer from declining lung function.
Szefler doesn't know if the children will notice the changes. "Asthmatics tend to accommodate to their illness as they get older," he said. "They realize what their limitations are and will adjust to that."
As for other meanings of the findings, Szefler said it's possible that declines in lung capacity could predict which asthmatic children will develop lifelong breathing problems. "About 5 to 10 percent go on to have severe asthma. This might be one of those components that makes the children stay sick," he said.
What to do? Szefler suggests that parents of asthmatic children make sure their doctors regularly monitor lung function. While specialists usually do so, other doctors may be less likely to order the tests, he said.
More information
To learn more about asthma and children, visit the American Academy of Allergy, Asthma and Immunology.
