ASTHMA
What is asthma?
Asthma is one of the most common chronic lung diseases worldwide. Asthma is:
 characterized by recurrent respiratory symptoms – especially wheezing, shortness of breath, chest
tightness, and coughing.
 heterogeneous – its symptoms and their intensity are different from person to person. Most people
with asthma have signs of inflammation in the airways of their lungs.
 variable – the symptoms wax and wane over time for each individual with asthma. Measurements
of lung function also vary over time.
During normal breathing, air flows freely into and out of the lungs. But when asthma is not under
control, the airways of the lungs are thick, swollen, and inflamed. The airways become overly sensitive
to environmental changes, and an asthma attack can happen easily. During an asthma attack, the lining of
the airways swells, muscles around the airways tighten, and mucus clogs the tiny airways in the lungs,
making breathing difficult.
Asthma symptoms vary from hour to hour, from day to day, from week to week, and over months. They
are often worse at night and in the early hours of the morning. The severity of asthma also varies from
individual to individual.
Although asthma cannot be cured, it can be effectively treated. Research shows that with proper
treatment, nearly all asthma patients can achieve and maintain good asthma control, enabling them to
participate in school, work, and other normal activities and prevent visits to the emergency department
and hospital.
What is asthma control and how is it achieved?
Scientists now think of asthma control as having two components: symptom control and future risk. This
means that a person’s asthma is under control when he or she has:
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No (or minimal) asthma symptoms.
No waking at night due to asthma.
No (or minimal) need to use “reliever” medication.
The ability to do normal physical activity and exercise.
Normal (or near-normal) lung function test results (for example, FEV1 or PEF).
No (or very infrequent) asthma attacks.
Low risk of future asthma attacks or other negative outcomes. Doctors consider many factors
when evaluating future risk. A few examples include a person’s history of severe asthma attacks,
smoking, side effects of asthma medications, and how regularly a person takes their asthma
medication as prescribed.
The goal of asthma treatment is to achieve and maintain control of the disease. In order to achieve control,
people need access to effective anti-asthma medications. They also need education to understand how to
take their medicines, how to avoid risk factors or “triggers” that make their asthma worse, and what to do
if their symptoms do worsen.
Most people with asthma need two types of medications: controller medications (especially antiinflammatory agents such as inhaled corticosteroids) that are taken every day over the long term to keep
symptoms and attacks from starting, and reliever medications (rapid-acting bronchodilators) that must be
kept on hand at all times to treat attacks or provide quick relief of symptoms.
How many people are affected by asthma?
An estimated 300 million people worldwide now have asthma according to the Global Burden of Asthma
Report, a compilation of published data on the prevalence and impact of asthma around the world.
Asthma affects people of all ethnic groups, socioeconomic levels, and ages. However, asthma often
develops during childhood. Indeed, asthma is the chronic disease most commonly causing absence from
school.
The Global Burden of Asthma Report was released by the Global Initiative for Asthma (GINA) on World
Asthma Day 2004, and remains one of the most comprehensive current assessments of the burden of
asthma worldwide. The Report also documents that many asthma patients around the world have unmet
needs related to their illness that lead to poor asthma control. In some areas, such as the Middle East and
the former socialist Baltic States, asthma is underdiagnosed and many people with asthma symptoms do
not realize they have the disease. Elsewhere, such as in Central Asia and Pakistan, inadequate knowledge
and widespread misconceptions about asthma and its treatment result in improper management of the
disease. In some areas cost limits patients’ access to asthma medications, but even in regions such as
Western Europe and North America asthma is undertreated or care falls short of that recommended by
evidence-based guidelines.
The Report, which is available from www.ginasthma.org, also documents that the prevalence of asthma is
increasing throughout the world, especially as communities adopt Western lifestyles and become
urbanized. It is estimated that there may be an additional 100 million persons with asthma by 2025.
One of the most serious indicators of lack of asthma control is hospitalization. Asthma-related
hospitalizations pose a heavy social and economic burden, and are an indication that asthma treatment has
failed and needs to be improved. The vast majority of emergency visits caused by asthma could be
avoided if patients knew how to use medication when their symptoms increase.
On World Asthma Day 2010, GINA launched a global campaign to encourage governments, health
departments, and health care workers worldwide to improve asthma control and reduce hospitalization
50% over the course of 5 years. In many parts of the world this challenge has been embraced. For
example, in British Columbia, Canada and in Finland reductions greater than 50% have been seen. GINA
will continue to advocate for this target and plans to systematically review published data to assess
changes in asthma hospitalization rates throughout the world.
What causes asthma?
The causes of asthma are not well understood, and the rapid increase in asthma prevalence around the
world is one of the biggest mysteries in modern medicine. In the 1990s, scientists thought that diesel
exhaust and other pollutants might be causing the asthma epidemic. However, they now believe that the
picture is more complex. Many scientists are examining the role of genetic factors in causing asthma, and
researchers are also looking at how the immune system develops in early life.
The causes of asthma attacks, however, are better understood. People with asthma have chronic
inflammation in their lungs, and airways that narrow more easily than those of people without asthma in
response to a variety of factors. The factors that can set off an asthma attack (sometimes called “triggers”)
include inhaled allergens (such as dust mites, pollen, and cat and dog allergens), tobacco smoke, air
pollution, exercise, strong emotional expressions (such as crying or laughing hard), chemical irritants, and
certain drugs (aspirin and beta-blockers). Each person with asthma reacts to a different set of factors, and
identification of these factors and how to avoid them is a major step for each individual in learning how to
control their disease.
How is asthma diagnosed?
A careful medical history, a physical examination, and tests of lung function provide the information
needed to diagnose asthma. A careful medical history will include questions about a person’s respiratory
symptoms and the pattern of these symptoms, especially whether they vary over time. The most reliable
way to measure lung function for asthma diagnosis is spirometry, a simple, painless test performed in a
health care professional’s office. Spirometry shows that most people with asthma have expiratory airflow
limitation – meaning that they cannot breathe out as fast or as hard as normal – that varies over time or is
reversible with asthma medications. Health care workers have various ways of documenting variable and
reversible airflow limitation.
Measurement of lung function is also useful to monitor the level of asthma control. This may be done
with spirometry or peak flow monitoring. Peak flow measures the maximum speed at which air can flow
out of the lungs and can be tested with portable, plastic peak flow meters ideal for use in home and work
settings.
How can I learn more?
More details about asthma and an effective, evidence-based asthma management program can be found in
the GINA documents available at www.ginasthma.org. In addition to producing a variety of educational
documents, GINA organizes World Asthma Day, an annual awareness-raising event held each May.