Getting at the true underlying cause of the climb will require better ways of distinguishing among various possible types of asthma. Major asthma research networks supported by the National Institutes of Health have begun recording the details of thousands of individuals’ symptoms and treatments. As the results are gathered and analyzed, researchers hope to identify clusters of asthma cases that have different causes and respond to different treatments. The hope is that “if you come in with these characteristics in asthma, we can anticipate what the prognosis is going to be and what the most effective treatment for you is going to be,” says William W. Busse of the University of Wisconsin School of Medicine and Public Health, who is part of one such network.
It will take years to understand fully whether microbial exposure, lifestyle changes or the obesity epidemic is more important in explaining the continuing increase in asthma rates. But one thing is clear: the hygiene hypothesis was just the beginning.
This article was originally published with the title Why Are Asthma Rates Soaring?.