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Asthma

Asthma is a chronic health disorder affecting a substantial proportion of children and adults worldwide. It is characterized by coughing, shortness of breath, chest tightness and wheezing. Asthma symptoms and attacks (episodes of more severe shortness of breath) usually occur after exercise or exposure to allergens, viral respiratory infections, irritant fumes or gases. These exposures cause an inflammation of the airway wall and an abnormal narrowing of the airways, which lead to asthma symptoms. Effective treatment can prevent the onset of symptoms in response to these triggers and can control symptoms once they occur.

Risk Factors

Longitudinal studies suggest that susceptibility to childhood asthma is determined during fetal development and in the first three to five years of life. A number of possible risk factors have been suggested for the development of asthma including the following:

  • Family history of allergy and allergic disorders (including hay fever, asthma and eczema);
  • High exposure of susceptible children to airborne allergens (pets, house dust mites, cockroaches, mould) in the first years of life;
  • Exposure to tobacco smoke, including in utero exposure
  • Frequent respiratory infections early in life
  • Low birth weight and respiratory distress syndrome (RDS).

Managing Asthma

Facts & Figures

Knowledge Development and Exchange

Initiatives, Strategies, Systems and Programs


The National Lung Health Framework External link
is a 'Made in Canada' action plan developed by and for a wide range of stakeholders working to improve lung health. Its coordinated approach to the prevention and management of respiratory diseases, including asthma, will have a significant positive impact on the state of lung health in Canada.