Risk Factors for Developing Asthma

DR. SOPHOCLES: What are some of the identified risk factors for developing asthma?
DR. COX: What they identified as risk factors for developing asthma was being sensitive to house dust mites. For persistent wheezers the ratio was 2.41 or those who had wheezed and relapsed, the odds ratio was 2.18. Airway hyper-responsiveness or bronchial challenges predicted persistent wheezing or relapse. For females, there was an increase risk for persistent wheezing with an odds ratio of 1.7. Smoking at age 21 also inceased the risk for persistent wheezing with an odds ratio of 1.84. The earlier the onset of symptoms, the greater the risk of relapse; and pulmonary function tests were consistently lower in those with persistent wheezing than those without persistent wheezing.

So in summary, there appears to be a greater loss of lung function in asthmatics. We are not sure if we can prevent this loss of lung function with adequate controller therapy. We do know that the medicines we currently have for asthma, the controller medications, do not appear to have a sustained disease modifying effect after they are discontinued. We know that the loss of lung function with asthma may occur early but it may not be progressive. It may plateau after the initial loss.
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DR. SOPHOCLES: There have been some differences of opinion on the hygiene theory. Is it still considered a factor?
DR. COX: It was very popular, then was more debated, and now it is coming around again. I don’t think it is the explanation for asthma for all people, but it may be one of them. We’re not allowing ourselves early in our immune development to teach our immune system through our environmental exposures what direction it should go in. The feeling is if you allow these natural infections to occur, there is a shift toward Th1, the non-allergy pathway, and that if you intervene and don’t allow the infection to occur, it continues to go toward the Th2 pathway.
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