According to the most recent study of asthma prevalence conducted by the Centers for Disease Control and Prevention, 31.3 million people (114 people per 1,000 – U.S.) had ever been diagnosed with asthma during their lifetime.

When race/ethnicity is considered, current asthma prevalence was about 10% higher among non-Hispanic blacks compared to non-Hispanic whites and about 40% higher compared to Hispanics. Females had a 30% higher prevalence compared to males. However, this pattern was reversed among children. The current asthma prevalence rate for boys aged 0-17 years (99 per 1,000) was over 30% higher than the rate among girls (74 per 1,000).

One of the defining characteristics of asthma is that the airway obstruction is reversible (though not always completely reversible) and may resolve on its own or with treatment.

Since the airway obstruction is variable, asthma may be described as “episodic” in that most people who have it breathe normally or near normally between episodes or acute attacks. In addition to being episodic, asthma is also considered to be chronic (an ongoing problem) and people with asthma have airways that remain inflamed and may get constricted after exposure to an asthma trigger.