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Ontario study first population-wide look at childhood asthma in Canada


A new report from the Institute for Clinical Evaluative Sciences (ICES) released for World Asthma Day (May 4) marks the first population-based study in Canada to look at the impact of asthma on children.

Researchers with ICES and The Hospital for Sick Children (Sick Kids) tracked Ontario children from 0 to 9 years of age between 1995 and 1999. Within this group they examined the incidence (new cases) and prevalence (existing cases) of childhood asthma, the death rate of children with asthma, differences in physician visits and hospitalizations among children with asthma and the general pediatric population, and seasonal and geographic variations of healthcare use by children with asthma.


  • There were over 228,000 new cases of childhood asthma during the study period (1995-1999).
  • One out of every five children aged 0 to 9 years had asthma in 1999. 
  • Compared with the general pediatric population, children with asthma cost OHIP over $100 more per child per year and contributed to over 1/3 of the total OHIP expenditure.
  • Healthcare use by children with asthma remained notably higher than the general pediatric population during the study period. However, their mortality rate was much lower than the general population.

“Children are the most affected by asthma and this study not only confirms the enormous burden of illness asthma places on children and their families, but also the tremendous pressure it exerts on the Ontario healthcare system in general,” said study lead author, Dr. Teresa To, a senior scientist in the Sick Kids Research Institute, an associate professor in the Department of Public Health Sciences at the University of Toronto, and an ICES senior adjunct scientist.

“Our research serves as a benchmark to monitor future changes in asthma diagnosis, treatment, management and health services use both within Ontario and nation-wide. As well, it lays the foundation for researchers to identify barriers to asthma management, for clinicians to study factors that put children at higher risk for asthma and asthma attacks, and for policy makers to more accurately target health programs,” Dr. To added.

This research was funded by Health Canada, the Ontario Ministry of Health and Long-Term Care, and The Hospital for Sick Children Foundation. Dr. To is supported by an Ontario Ministry of Health and Long-Term Care/Canadian Institutes of Health Research Investigator Award.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners and practitioners to make decisions about care delivery and to develop policy.

The Hospital for Sick Children, affiliated with the University of Toronto, is Canada’s most research-intensive hospital and the largest centre dedicated to improving children's health in the country. Its mission is to provide the best in family-centred, compassionate care, to lead in scientific and clinical advancement, and to prepare the next generation of leaders in child health. For more information, please visit www.sickkids.ca.


  • Julie Argles
  • Media Relations Officer, ICES
  • (416) 480-4055 ext. 3602 or cell (416) 432-8143
  • [email protected]
  • Laura Greer
  • Public Affairs, Sick Kids
  • (416) 813-5046 or pager (416) 899-7746
  • [email protected]


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