Why is asthma increasing among children?
Asthma is on the rise, especially among children. The Centers for Disease Control (CDC) reported a prevalence of asthma in children of 3.6% in 1980; by 2003 this had risen to 5.8%, which represents a 60% rise in the number of cases. The numbers are going up in adults, too, but they are most dramatic in children. From my perspective in the PICU, there is no question that this problem is increasing; we are seeing more and more children with the sort of severe asthma attacks that land them in the PICU.
Asthma is really a clinical syndrome more than a specific disease. By that I mean it represents a tendency of a child’s lungs to respond to a variety of triggers — things like allergies, tobacco smoke, and simple viral colds — in a characteristic way. This response is constriction of the smaller airways of the lungs, increased mucous in the airways, and inflammation around the airways. The result is difficulty breathing, mostly manifested by difficulty getting air out of the lungs. Trouble getting air out with each breath causes a child to have the characteristic wheezing sound asthma produces. Besides wheezing, a severe attack causes the child to have difficulty getting enough oxygen into the bloodstream.
What’s happening? Is it just that we’re noticing (and labeling with asthma) more children these days, or does this represent a real increase in the disease? The experts all agree that these numbers indicate a real increase, not some kind of artifact. They point to several possible culprits. Since many asthmatics react to environmental triggers, a decline in air quality is a leading candidate. In fact, various studies have shown that children living in dense, urban environments, especially near busy traffic areas, have a higer risk of asthma. Body weight also contributes to asthma, and the steady rise in childhood obesity likely contributes, too. The fact that “asthma” is probably not just one thing makes it all that more difficult to figure out what is causing this slow-rolling epidemic.
The good news is that, even though the number of children with asthma is on the rise, the therapies we have now are much more effective than those of thirty years ago, so the number of severe complications from asthma is actually decreasing.