WEDNESDAY, Oct. 8, 2003 (HealthDayNews) -- One in four children with asthma will continue to struggle with the disease in adulthood.
What's more, the younger a person is when he or she develops asthma, the more likely they are to have it as an adult. Also, being female, a smoker, having persistently low lung function and being exposed to dust mites further increases the chances of continuing asthma.
Those are the findings of a study in the Oct. 9 issue of the New England Journal of Medicine.
This is the first study to look at a regular population of children, rather than just high-risk children, and it could provide some clues on how to prevent asthma, or at least more serious forms of the lung disease.
"Ninety percent [of people with asthma] can have normal lives, but we have no way to change the course of the disease," says Dr. Fernando D. Martinez, author of an accompanying editorial in the journal and director of the Arizona Respiratory Center at the University of Arizona. "We need to know the natural history, who is going to get bad disease, if we are going to go to the next step, which is comprehensive prevention."
While inner-city environments have long been known to contain risk factors for asthma, the new study looked at a far different environment -- that of the small city of Dunedin on the South Island of New Zealand.
The researchers studied 613 children born from April 1972 through March 1973 in Dunedin, which is where Dr. Malcolm Sears, the study's lead author, was located at the time.
The children were assessed through the ages of 9 to 26 several times with the aid of questionnaires, pulmonary-function tests and skin-prick allergy tests.
Almost three-quarters of the study population (72.6 percent) reported wheezing at some point in time. For the purposes of this study, "wheezing" and "asthma" are "more or less the same thing," says Sears, who is now research director at the Firestone Institute for Respiratory Health in Hamilton, Ontario. There was, however, a spectrum of severity, and most of the wheezing reported was mild and transient.
Almost 15 percent of the study participants had wheezing that persisted from childhood to adulthood. Of those with wheezing in childhood, 27.4 percent went into remission, but 12.4 percent subsequently relapsed.
The risk factors for both persistent and relapsing asthma were almost identical: a child who was sensitized to house dust mites had a more than two times greater chance of having asthma into adulthood; those with airways that constricted easily or to a large degree had about a three times greater chance of continuing asthma. Females were 70 percent more likely to have persistent wheezing. And those who smoked at age 21 were 84 percent more likely to also have persistent wheezing.
The earlier the asthma started, the greater the risk of it becoming a permanent part of the patient's life, the researchers found. This seems to indicate that environmental factors play some role in triggering the onset of the disease.
Even though it will likely take years before researchers untangle the different factors at play with asthma, the study may offer some immediate benefits.
"It tells us as clinicians that children who have these risk factors need to be watched closely," says Dr. Jonathan Field, director of the Pediatric Allergy and Asthma Clinic at New York University Medical Center in New York City. "There's always going to be some risk whether genetic or environmental, but things we can work on we're now more compelled to work on."
Adds Sears: "We need to find better ways of identifying high-risk cases and treating more actively in early childhood. Once in middle childhood, we have already set the scene for the future. The challenge is how do we identify it [asthma] early enough and how do we treat it effectively."
More information
For more on asthma in children, visit the American Lung Association. The National Institute of Allergy and Infectious Diseases has more on asthma basics.
