2 tables omitted
Asthma is a chronic illness that has been increasing in prevalence in
the United States since 1980.1 In 2000, asthma accounted for 4,487
deaths, approximately 465,000 hospitalizations, an estimated 1.8 million emergency
department (ED) visits, and approximately 10.4 million physician office visits
among persons of all ages.2 To provide prevalence data for state
and local health department asthma programs, the Behavioral Risk Factor Surveillance
System (BRFSS) collects data each year from the 50 states, the District of
Columbia, and three U.S. territories. This report summarizes asthma prevalence
data for adults collected from the 2001 BRFSS survey and from the eight states
that used the adult asthma history module. Findings from BRFSS indicate that
approximately 7.2% of U.S. adults have current asthma. ED visits for asthma
varied more than any other characteristic among the eight states that used
the adult asthma history module. In Mississippi, 67.3% of respondents with
current asthma reported no ED visits during the preceding 12 months, compared
with 87.6% in Washington state. Continued use of the BRFSS asthma prevalence
questions and the asthma history module will allow state health departments
to monitor trends in asthma prevalence and control and to direct public health
BRFSS is a state-based, random-digit–dialed survey of the noninstitutionalized
civilian U.S. population aged ≥18 years; the survey collects information
about modifiable risk factors for chronic diseases and other leading causes
of death.3 In 2001, two asthma questions were used as part of the
core survey by the 50 states, the District of Columbia, Guam, Puerto Rico,
and the Virgin Islands. Lifetime asthma was defined as answering "yes" to
the question, "Have you ever been told by a doctor, nurse, or other health
professional that you have asthma?" Current asthma was defined as answering
"yes" to the lifetime question and to the question, "Do you still have asthma?"
Weighted prevalence estimates and 95% confidence intervals (CIs) were calculated
by using SUDAAN to account for the complex survey design.4
The median response rate for all 54 BRFSS reporting areas was 51.1%
(range: 33.3% [New Jersey]–81.5% [Puerto Rico]).5 The overall
prevalence of lifetime asthma among adults was 11.0% (95% CI = 10.8%-11.2%)
(n = 204,797). Lifetime asthma prevalence from all 54 reporting areas ranged
from 7.5% in Guam to 19.6% in Puerto Rico. Among the 50 states, lifetime asthma
ranged from 8.4% in Nebraska to 13.3% in Nevada. During 2001, an estimated
15.1 million adults in the United States and the District of Columbia had
current asthma; the overall prevalence was 7.2% (95% CI = 7.0%-7.4%). Current
asthma prevalence from all 54 reporting areas ranged from 3.5% in Guam to
9.5% in Puerto Rico. Among the 50 states, current asthma prevalence ranged
from 5.3% (Louisiana and South Dakota) to 9.5% (Massachusetts). Current asthma
was higher among persons who were multiple race and non-Hispanic (12.2%),
followed by non-Hispanic blacks (8.5%), non-Hispanic whites (7.2%), other
race and non-Hispanic (5.9%), and Hispanics (5.7%).
For this report, seven questions (of the nine questions in the asthma
history module) were used to measure the level of asthma control in respondents
with current asthma. Respondents were asked to report the number of visits
to an ED, urgent (unscheduled) doctor visits, or routine check-ups; the number
of days they could not perform their usual activities, had trouble with sleep,
or had asthma symptoms; and whether they had an asthma attack or episode during
the preceding 12 months.
The overall current asthma prevalence for the eight states that used
the module was 7.7% (95% CI = 7.3%-8.1%). Current asthma prevalence varied
from 5.3% (South Dakota) to 9.0% (Michigan). Among respondents with current
asthma, 82.7% reported no visits to an ED during the preceding 12 months;
71.0% reported no urgent visits to a physician; and 54.4% reported routine
check-ups for asthma during the preceding 12 months. An estimated 71.6% of
respondents with current asthma reported no days of activity limitation, 60.9%
reported no days of disturbed sleep, and 21.8% reported having no symptoms
during the preceding 30 days. An estimated 47.2% of respondents with current
asthma reported no asthma attack or episode during the preceding 12 months.
The control characteristics presented were configured so high values represent
positive aspects of asthma management. Over time, improved asthma management
would result in increased values on each of the seven control characteristics.
On each of the seven asthma-control questions, several states were above
or below the CI for the eight-state total. South Dakota was above the CI on
six of seven questions, indicating above-average asthma control. Michigan,
with the highest current asthma prevalence in the eight states, was within
the eight-state total CI on all questions, indicating an average level of
asthma control among residents with current asthma.
L Rhodes, MPH, JE Moorman, MS, SC Redd, MD, DM Mannino, MD, Div of Environmental
Hazards and Health Effects, National Center for Environmental Health, CDC.
Asthma is a multifactorial lung disease that causes wheezing, shortness
of breath, coughing, and chest tightness. It is often associated with familial,
allergenic, socioeconomic, psychological, and environmental factors.6,7 Asthma affects proportionately more children than adults, women
than men, and nonwhites than whites.1 Morbidity and mortality can
be partly preventable with better medical, environmental, and self management.
The 2001 BRFSS lifetime prevalence estimate (11.0%) was slightly higher
than the 2000 BRFSS lifetime estimate (10.5%). This difference might be an
actual increase in prevalence or might be associated with a minor change in
question wording in 2001. The current asthma prevalence in 2001 (7.2%) was
the same as in 2000. The findings in this report indicate no consistent regional
pattern in asthma prevalence and some variability among the states. Possible
reasons for this variability include demographic, socioeconomic (e.g., income
and education levels), and environmental factors (e.g., outdoor air pollution
and climate), physician diagnostic procedures, or data-collection practices.
In 2001, current asthma prevalence estimates were comparable with 2000 BRFSS
estimates for whites, blacks, and persons of other races. However, the change
in the positioning of the race and ethnicity questions on the BRFSS core survey
and the addition of a multiple race question could have affected the asthma
prevalence estimates when both race and ethnicity are considered.
The findings in this report are subject to at least three limitations.
First, the median response rate for BRFSS was low (51.1%); however, asthma
prevalence is similar to estimates in other surveys with higher response rates
(e.g., National Health Interview Survey). Second, BRFSS does not measure asthma
prevalence among institutionalized adults, the military, children aged <18
years, and residents without telephones; the percentage of households with
telephones ranged from 87% (Mississippi) to 98% (Massachusetts).8 Asthma
prevalence in households without telephones might be different than in those
with telephones. Finally, the validity of self-reported asthma status in BRFSS
is unknown. BRFSS case definitions include respondents who have been told
by a physician they have asthma; either the physician's diagnosis or the respondent's
recall of that diagnosis might be inaccurate. A 1993 review of asthma questionnaires
reported a mean sensitivity of 68% (range: 48%-100%) and a mean specificity
of 94% (range: 78%-100%) when self-reported asthma was compared with a clinical
diagnosis of asthma.9
Use of BRFSS asthma lifetime and current prevalence questions allows
state health departments to monitor trends in asthma prevalence and to direct
asthma management. Combined with the existing adult asthma history module,
health departments can examine detailed asthma characteristics within their
states. BRFSS remains the only comprehensive source of state-level surveillance
data for asthma and other chronic diseases.
This report is based on data contributed by state BRFSS coordinators.
References: 9 available
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