National surveillance for asthma--United States, 1980-2004.

The findings in this report suggest that from 1980 through the mid-1990s, increases in asthma prevalence played a substantial role in the increases in patient encounter measures used in asthma surveillance. Because no primary strategies for preventing asthma have been identified, efforts to control asthma exacerbations through interventions that promote adhering to proper medical regimens and reducing exposures to causes of asthma exacerbations should continue to be pursued.