Asthma is a chronic inflammatory disease of the airways that has a global impact and affects both children and adults. Currently, over twenty-five million individuals in the United States have asthma and globally, 300 million are said to be asthmatic. Asthma also affects both sexes. There is not a single cause of asthma but recent studies have shown a critical role for both genetic and environmental factors play a role. Scientists have identified more than 100 “candidate” genes associated with asthma. Environmental factors are equally important. For example childhood exposures to farming and the environmental exposures associated with rural farming is protective against the development of asthma. In contrast, viral respiratory infection in the early life have a temporal relationship with asthma onset. Early life exposure to allergens and pollutants as well as dietary factors and antibiotic use can increase the risk for subsequent asthma. In utero exposures may be particularly important as the airways and immune system are still developing and this is an area of active research.
Asthma was initially treated and managed with drugs that target airway smooth muscle that reduces bronchoconstriction, such as b2-agonists. These drugs are still a main form of treatment. However, research in the last few decades has identified that many subjects with asthma have airway inflammation that is characterized by a type 2 or Th2 response in the lung, which is characterized by allergy, and eosinophilic inflammation in the lung. This aspect of the disease is targeted by inhaled anti-inflammatory compounds such as inhaled corticosteroids (ICS). Although this two-pronged approach is effective in many patients, newer biological therapies that antagonize molecules important in type 2 inflammation have been developed for patients that have more refractory disease. Although deaths related to asthma have decreased since the early 2000s, there are still about 3,500 deaths per year in this country. Females have an asthma death rate 45% higher than men. Non-Hispanic blacks have a death rate that is 200% higher than that for Non-Hispanic whites.
Important Facts About Asthma and Allergy |
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