"The proportion of Americans with asthma increased from 7.3% in 2001 to 8.4% in 2010, marking the highest level ever, the U.S. Centers for Disease Control and Prevention said Tuesday. In 2010, an estimated 18.7 million adults and 7 million children had the disease -- one in every 12 Americans."

"Overall, about 29.1 million adults have been diagnosed with asthma at some point in their lives, but many of those were misdiagnosed or have apparently recovered, leading to the current figure of 18.7 million.

Asthma is a chronic airway disorder characterized by periods of irreversible airflow obstruction caused by inflammation of the airway and contraction of small muscles surrounding it. It can be triggered by exercise, infections, allergies, occupational exposures and airborne irritants such as tobacco smoke. Symptoms include wheezing, coughing, shortness of breath and chest tightness. Symptoms can usually be controlled with a variety of drugs, but there is no known cure and no known way to prevent development of the disorder."

Thomas H. Maugh II reports for the Los Angeles Times May 15, 2012.
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