More important than Maine’s first-in-the-nation rank for cases of asthma is the national doubling of this affliction during the last two decades. Though when properly treated, asthma is manageable for most people, the lack of a clear cause for the increase is worrisome and demands further research.

The Centers for Disease Control and Prevention reports that the primary cause of asthma, a constructing of the lungs’ airways, is genetic predisposition, but that it can be set off by any number of conditions, including dander from animal hair, molds, dust mites, smoke particulate matter, etc. Its first-ever state-by-state review of asthma, asking 182,000 people whether they had asthma or had ever had it ended up ranking Maine first, with 8.9 percent, among current cases. The national average is 7.2 percent. However, compared with studies in 1980, these rates appear to have more than doubled.

Asthma is often seen as an urban disease, but given some conditions in Maine – high smoking rates, low exercise, lower income (asthma rates are inversely proportional to income rates) and number of wood stoves – having asthma more often triggered here is not surprising. It might, however, cause at least one policy change in Washington. The CDC has a special program to investigate asthma in urban areas, but its study suggests that urban areas have no higher asthma rates than rural places. Of far more concern should be the increasing number of people who have been treated for the disease.

One theory is that Americans have become more germ-conscious now and are shield infants so much that the infants do not develop sufficient immune systems, causing their immune cells to over-react to harmless substances like dust. It is an interesting idea, but it would have to be squared with survey after survey that show Americans spending less time than ever cleaning their homes, potentially leaving an ample supply of germs to which infants would be exposed. Perhaps a more important avenue to pursue is the steady increase in the number and variety of chemicals now found in homes and the increase in the amount of air pollution in some regions.

Nearly one school-aged child in 13 has asthma, with the rate for this age group rising faster than any other. The CDC estimates that asthma accounts not only for 10 million missed school days and cost billions in health care dollars per year, but that the children affected miss out on important parts of life. The new national study points to the importance, especially for Maine, of a much fuller investigation into this disease to find out why so many more people are suffering from it now than just a generation ago.