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Asthma - Description
Asthma: A Concern for
Minority Populations
Overview
Asthma is a growing concern in this country, particularly in
inner-city African-American and Latino populations. Asthma is a chronic lung
disease characterized by episodes of airflow obstruction. Symptoms of an asthma
attack include coughing, wheezing, shortness of breath, and chest tightness.
Asthma occurs in people who are predisposed to develop asthma because of genetic
and environmental factors that determine susceptibility. A variety of
"triggers" may initiate or worsen an asthma attack, including viral
respiratory infections, exercise, and exposure to allergens or to airway
irritants such as tobacco smoke and certain environmental pollutants.
Once asthma sufferers learn what conditions prompt their
attacks, they can take steps to control their environment and avoid these
triggers. However, medical treatment with anti-inflammatory agents (especially
inhaled steroids) and bronchodilators is usually necessary to prevent and
control attacks. With optimal management, control of asthma is usually an
attainable goal.
The Impact of Asthma
Asthma affects nearly 15 million Americans, more than 5
percent of the U.S. population. In 1991, asthma claimed approximately 5,000
lives. After a decade of steady decline in the 1970s, the prevalence of asthma,
hospitalizations for asthma, and mortality due to asthma each increased during
the 1980s.
In 1993, among children and young adults, African Americans
were three to four times more likely than whites to be hospitalized for asthma,
and were four to six times more likely to die from asthma. Poverty, substandard
housing that results in increased exposure to certain indoor allergens, lack of
education, inadequate access to health care, and the failure to take appropriate
medications may all contribute to the risk of having a severe asthma attack or,
more tragically, of dying from asthma.
The scope of the health care problem caused by asthma lies
not only in the large number of Americans with the disease, but also in the
limitations that asthma can impose on daily life. Asthma is the leading cause of
school absenteeism due to chronic illness and is the second most important
respiratory condition as a cause of home confinement for adults. Each year,
asthma causes more than 18 million days of restricted activity, and millions of
visits to physicians' offices and emergency rooms. A recent study found that
children with asthma lose an extra 10 million school days each year; this
problem is compounded by an estimated $1 billion in lost productivity for their
working parents. In 1990, asthma-related health care cost our nation
approximately $6.2 billion.
National Cooperative Inner-City Asthma
Studies
In 1991, to address the concerns about asthma in the inner
city, the National Institute of Allergy and Infectious Diseases (NIAID), a
component of the National Institutes of Health, launched the first National
Cooperative Inner-City Asthma Study. The primary aim of the study was to
identify factors responsible for the rise in asthma among inner-city children
and to test new strategies for asthma intervention. The eight centers funded by
NIAID included:
- Albert Einstein School of Medicine, New York, NY;
- Case Western Reserve University, Cleveland, OH;
- Children's Memorial Hospital, Chicago, IL;
- Henry Ford Hospital, Detroit, MI;
- Howard University, Washington, DC;
- The Johns Hopkins University, Baltimore, MD;
- Mt. Sinai Medical Center, New York, NY;
- Washington University, St. Louis, MO.
Phase I of the first National Cooperative Inner-City Asthma
Study (1991-1994) was designed to identify factors associated with severity of
asthma in children ages 4-11. The second phase, completed in February 1996,
studied the effectiveness of a comprehensive program to develop improved
knowledge about asthma, to promote better asthma self-management skills, and to
eliminate or decrease exposure to environmental factors associated with
increased morbidity from asthma.
Phase I enrolled 1,528 children and their families. The
study population was 73 percent African American, 20 percent Latino, and 7
percent Caucasian. Asthma risk factors found to be present in these urban
families included: high levels of indoor allergens, especially cockroach
allergen; high levels of tobacco smoking among family members and caretakers;
and high indoor levels of nitrogen dioxide, a respiratory irritant produced by
inadequately vented stoves and heating appliances. Many patients also reported
difficulties in obtaining follow-up care for their asthma. Low socioeconomic
status and African-American race were independent risk factors for allergic
sensitization to cockroach allergens. Thus, new approaches to reduce exposure to
cockroach allergens may be very useful in controlling asthma.
More than 1,000 children were enrolled in Phase II of the
study. Several sites used a Spanish language program in addition to the standard
English language program. These sites employed bilingual counselors and modified
the intervention to account for cultural issues unique to a Latino population. A
key component of the Phase II intervention was the use of an "asthma care
counselor" whose primary role was to teach and monitor acquisition of
asthma self-management skills. While the results are still preliminary, children
in the intervention limb of the study had striking reductions in major symptoms,
in school absenteeism, in hospitalizations, and in emergency room visits for
asthma.
Based on the success of the first National Cooperative
Inner-City Asthma Study, NIAID and the National Institute of Environmental
Health Sciences (NIEHS) recently initiated a second cooperative multicenter
study. A major objective is to extend and disseminate the findings of the first
National Cooperative Inner-City Asthma Study. This continuation includes new
educational programs for patients and physicians, and focuses on
community-specific interventions and on the relationship between asthma
morbidity and the environment. The seven Centers funded in FY1996 are:
- Albert Einstein School of Medicine, New York, NY;
- Boston University, Boston, MA;
- Children's Memorial Hospital, Chicago, IL;
- Mt. Sinai Medical Center, New York, NY;
- University of Arizona Health Sciences Center, Tucson, AZ;
- University of Texas Southwestern Medical Center, Dallas,
TX;
- Odessa Brown Children's Clinic, Seattle, WA.
NIAID Asthma Demonstration and Education Research
Projects
NIAID also supports 15 extramural Asthma, Allergic, and
Immunologic Diseases Cooperative Research Centers to conduct basic and clinical
research on mechanisms of disease and ways to prevent asthma, allergic, and
immunologic diseases. Each Center supports a Demonstration and Education
Research Project to study educational, behavioral, and environmental
interventions in underserved populations, especially ethnic minorities. All but
one of these projects focus on asthma. Additional Demonstration and Education
Research Projects have been established at university and clinic sites in
Atlanta, Boston, Miami, Dallas, and San Diego. At several of these sites,
researchers are developing interactive video games about asthma as well as other
educational and computer-based clinical management tools for inner-city health
care providers. These projects focus on different inner-city populations and
explore interventions other than those of the National Cooperative Inner-City
Asthma Study.
Studies on the Genetic Basis of Asthma
In collaboration with the National Heart, Lung, and Blood
Institute (NHLBI), NIAID is funding a cooperative study at four centers (Johns
Hopkins University, Baltimore, MD; University of Chicago, Chicago, IL;
University of Maryland, Baltimore, MD; and University of Minnesota, Minneapolis,
MN) to explore the genetic basis of asthma. This study is enrolling asthmatic
patients and their families (many of whom are from ethnic minorities) in order
to identify genes for asthma and for responsiveness to allergens. This study has
identified several candidate genes for asthma, some of which may be more common
in African-American populations. In other studies, investigators supported by
NIAID have identified a genetic change in interleukin-4 (IL-4), an
immune-signaling molecule involved in asthma and allergic responses, that
correlates with asthma severity. This change appears to be several-fold more
common among African Americans than among whites. Studies of such genes should
facilitate development of new and more potent and selective therapies, and may
help to identify patient populations who might respond best to a particular
drug.
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