**9.1. Overview/epidemiology**

Asthma was first defined in 1860 by Salter, a British clinician who ascertained that attacks were related to smooth muscle contraction. Asthma, at its core, is a chronic airway disease characterized by wheezing, coughing, and breathlessness with variable airway obstruction on pulmonary function testing. Asthma is a relatively common disease; recent reports by the Center for Disease Control (CDC) place its prevalence at approximately 12% (children) and 10% (adults) in the US. (www.cdc.gov) There appears to be a predominance of childhood asthma in non-Hispanic blacks, whereas non-Hispanic Whites, Hispanics, Asians, and Na‐ tive Americans all have similar frequencies of asthma. Additionally, the condition is signifi‐ cantly more common among females than males.
