Asthma Fact Sheet

Asthma Fact Sheet

What is Asthma?

Asthma is a chronic breathing disorder affecting both children and adults.1 It is characterized by:

  • Cough, severe shortness of breath, chest tightness and wheeze1 and usually occurs after exposure to allergens, viral infections and exercise or exposure to irritants such as fumes and cigarette smoke.2
  • Inflammation of the airway wall and abnormal narrowing of the airways which may lead to asthma symptoms.3
  • An asthma attack can be frightening with feelings of suffocation, breathlessness, and loss of control, and can be potentially life threatening.4
  • Asthma can develop at any age, but is most common in childhood.5
  • It is the leading cause of hospital admission for children.7

How Many Canadians Are Living With Asthma?

At present, almost 3 million Canadians are living with asthma or roughly 9.5% of the total population of Canada.

  • In 2005, 8.3% of Canadians ages 12 and older had asthma.12
  • In 2000, almost 16% of children age 4 to 11 had asthma.

What is the Lifetime Risk of Developing Asthma?

Canadians have a two in five chance - or a 40% risk - of being diagnosed with asthma before age 40.6

  • The risk of developing asthma is greatest during childhood, with 20% of children being diagnosed as asthmatic by 12 years of age.6
  • A further 20% of individuals will be diagnosed between the ages of 12 and 40 years.6

How Does Asthma Develop?

Possible risk factors for the development of asthma include:

  • Family history of allergies, asthma and eczema9
  • High exposure to airborne allergens (pet, dust mites, mould) in the first years of life9
  • Exposure to tobacco smoke9
  • Frequent respiratory infections early in life9
  • Low birth weight and respiratory distress syndrome (RDS) at birth9
  • Being overweight or obese10

The Facts about Asthma

Asthma Can Be Controlled. Yet despite this fact:

  • Sixty percent of individuals with asthma have poorly controlled disease, which can often restrict their daily activities.11 Thirty nine percent of individuals report limitation in their physical activity due to asthma.11 Twenty percent report absenteeism from school, work or social engagements due to asthma.11
  • Although 287 Canadians died of asthma in 2003, mortality rates for asthma have fallen since 1990.8

Asthma Triggers

Asthma triggers are allergens and irritants that can create breathing problems when people with asthma are exposed to them. Common triggers include:

  • Dust and dust mites
  • Pollens including tree, grass and ragweed pollens
  • Pets and other animals
  • Cigarette smoke
  • Colds/chest infections
  • Weather and air pollution
  • Cold air and high humidity
  • Food allergies

Asthma Control

Asthma is Controlled When:

  • Asthma symptoms occur less than four times per week
  • One wakes up at night less than once per week
  • One rarely misses school, work or social activities because of asthma symptoms
  • Asthma symptoms are usually mild
  • The need for the blue reliever medications is less than 4 times per week 
  • Physical activity is normal.

Revised 2007-04-24

  1. The Lung Association, What is Asthma? Accessed 2007-04-24 from
  2. The Lung Association, Provoking Factors. Accessed 2007-04-24 from
  3. The Lung Association, Asthma. Accessed 2007-04-24 from
  4. The Lung Association, Life-Threatening Reaction. Accessed 2007-04-24 from
  5. The Lung Association, Asthma Facts and Statistics. Accessed 2007-04-24 from
  6. ICES Report, Burden of Asthma, Sept 2006
  7. Stats Canada, Millar, Wayne J and Gerry B Hill. Childhood Asthma, Health reports, vol. 10, No 3 (Winter 1998); p 12
  8. ICES Report, Burden of Childhood Asthma, May 2004
  9. The Lung Association, Asthma: A Resource for Canadian Journalists, Page 3-4. Accessed 2007-04-24 from
  10. American Journal of Respiratory Critical Care Medicine, 2007
  11. Asthma in Canada A Landmark Survey, Accessed 2007-04-24 from
  12. Statistics Canada, Accessed 2007-04-24 from

Page Last Updated: 29/10/2019