Asthma Data and Surveillance
The Federal Liaison Group on Asthma (FLGA) is a subcommittee
of the National Asthma Education and Prevention Program (NAEPP).
The FLGA is comprised of representatives from 21 federal agencies
that have programmatic activities related to asthma. The FLGA
meets two to three times a year to explore ways of strengthening
federal coordination of asthma activities.
One of five focus areas of the FLGA is asthma data and surveillance.
FLGA members acknowledge that there is confusion about recent
national asthma prevalence estimates due to changes in National
Health Interview Survey (NHIS) methodology in 1997. To clear
up confusion among the public and policy makers, the FLGA
has developed two reference documents, Asthma:
These documents are intended to facilitate an informed and
consistent explanation by federal agencies for changes in
the asthma numbers, and to serve as a briefing outline in
preparation for interviews with the media, for public discussions,
and in preparation of written materials.
The National Center for Health Statistics of the Centers
for Disease Control and Prevention (CDC)--a member of the
FLGA--conducts the NHIS each year to collect data for estimating
asthma prevalence. Between 1997 and 2001, the changes in methodology
most affecting estimates were modifications to the sampling
frames, changes in wording to survey questions, and changes
in the combination and sequencing of questions asked. In a
given year, depending on what questions are asked, the resulting
data provides estimates of period prevalence of asthma, lifetime
diagnosis of asthma, asthma attack prevalence, and/or current
asthma prevalence. Based on the actual questions asked from
1980 through 2001, the resulting data has provided the following
|1980 - 1996:
||Period Prevalence of Asthma (used as a surrogate
for current asthma)
Based on the question, "During the past 12 months, did
anyone in the family have asthma? If yes, who?"
|1997 - 2000:
||Lifetime Diagnosis of Asthma
Asthma Attack Prevalence
Based on the questions, "Has a doctor or other health
professional ever told you that you had asthma?", followed
by, ÒDuring the last 12 months have you had an
episode of asthma or asthma attack?"
Lifetime Diagnosis of Asthma
Asthma Attack Prevalence
Based on the questions, ÒHas a doctor or other
health professional ever told you that you had asthma?",
followed by, ÒDo you still have asthma?", followed
by, "During the last 12 months have you had an episode
of asthma or asthma attack?"
For further information, please refer to the Asthma FAQs
and FAP attached. March 26, 2002