Has Asthma Prevalence Continued to Increase? A Quantifiable, but Convoluted, Answer

Jeanne Moorman, U.S. Centers for Disease Control and Prevention (CDC)
Clinton J. Alverson, U.S. Centers for Disease Control and Prevention (CDC)

The National Health Interview Survey (NHIS) has been the source of asthma prevalence data since 1979. In 1997, the NHIS underwent a major revision that drastically changed the concept of asthma prevalence. Prior to the revision, it measured a 12-month period prevalence, allowed both self and proxy responses, and did not require a physician diagnosis. Beginning in 1997, adult proxy reporting was eliminated, a physician’s diagnosis was required and the question wording drastically changed to a lifetime prevalence concept. Because of these three changes, the historic asthma prevalence time trend was terminated. The primary goal of this analysis is to provide annual estimates of time trends back to 1979 and future projections through 2010 for the historic 12-month asthma period prevalence measure and a current asthma point prevalence measure. For each asthma prevalence measure we will provide annual estimates for both the percent prevalence and the number of cases.