Over the period several diseases have increased in prevalence or severity. Asthma and hay fever suggest a similar time also. This coincident of time frame has been taken to suggest that there could be a common cause. This journal described that these disease are all related to some changes in “cleanlines” or “hygiene” that have resulted in decreased activation of a common mechanism such T regulator cells, which produce interleukin-10 (IL-10) or transforming growth factor-beta.
Several hypotheses have been tried to explain the increase in asthma’s symptoms or disease. Here, the question was pointing about Is an increase in allergy or hay fever a necessary in asthma, a paralel event, or separate?, then why did the increase in asthma have such a consistent time course througout countries where changes in infectious disease have occured very differently? and the last question is why asthma is more common and more severe in some countries than in other countries that have had an equal scale of increase over the same time course?
Since 1994, there have been multiple reports of an association between elevated body mass index (BMI) and asthma and changes in physical activity could be related to bronchospasm. However, there are aspects of lifestyle that could be relevant toprevalence and severity of asthma : diet, physical activity, and obesity.
A brief explanation how physical activity would have benefiacial effect on asthma were full expansion of the lungs had a more potent effect on bronchial smooth muscle than isoprenaline. It is obvious that the expansion of the lungs is decreased during prolonged periods of sitting down and a different explanation is that physical activity can be an “anti-inflammatory”.
There were many variables conditions that easily confused with exercise-induced asthma or nocturnal asthma. So, there are excellent reasons for asking whether lifestyle changes have contributed to the increased prevalence or severity of asthma. But it seems unlikely that it occurs on normal lungs, thus the hypothesis has to be that decreased physical activity in patients who are allergic can allow persistent or increased severity of wheezing.
On conclusion, the experts stated that once water supplies are clean, and major infectious diseases have been controlled, allergic diseases will appear. It is the combination of the control of infectious disease, prolonged indoor exposure, and sedentary lifestyle that is the key to severity. Using this analysis the severity of asthma in children at many countries such as North American, New York, Atlanta, Philadelphia, and Washington DC who spend long hours indoors, high exposure to mite, cockroach, rodent allergies and very low levels of physical activity becomes much easier to explain. And it appears that these combined factors are the key to the asthma epidemic and, in particular, the key to the rise in severity.
The author of this journal were Thomas A.E, Platts-Mills Professor of Medicine at the University of Virginia Asthma and Allergic Diseases Center, Charlottesville, Virginia, United States of America. E-mail: tap2z@cms.mail.virginia.edu.
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