Prevalence and Definition

Prevalence of Asthma

• Asthma is the most common chronic illness affecting children
• Asthma affects 2.3 million Canadians over the age of 4 years with an estimated total cost of between $504 million and $648 million in 1991.
• It accounts for more missed school days and limitations in daily activities than any other childhood illness
• In Ontario, 10 to 13 % of children from birth to 18 years have asthma.
• Asthma is one of the main reasons children are admitted to hospital and is also one of the main reasons children are seen repeatedly in the emergency department.

Definition

Asthma, a chronic inflammatory disorder of the airways. It is characterized by paroxysmal or persistent symptoms such as

• dyspnea
• chest tightness,
• wheezing,
• sputum production and
• cough associated with variable airflow limitation and a variable degree of airway hyper-responsiveness to triggers.

An asthma episode may begin suddenly, or may have a slow onset with a gradual worsening of symptoms.

These episodes, which can last for a few minutes to several days, are attributed to a hyper-responsiveness of the airways and are typically reversible.