What is the best estimate of the prevalence of autism spectrum disorders in Canada?
The National Epidemiologic Database for the Study of Autism in Canada (NEDSAC) has been monitoring the prevalence of autism spectrum disorders (“autism”) in Newfoundland and Labrador, Prince Edward Island and Southeastern Ontario since 2003. Based on information from our most recent year of data collection (2010 in Prince Edward Island and Southeastern Ontario; 2008 in Newfoundland and Labrador), our best estimate of the prevalence of autism spectrum disorders in Canada is 1 per 94 children.
What does “prevalence” actually mean, and how is it calculated?
The prevalence of a condition refers to what proportion of the population has that condition at a certain point in time. For NEDSAC, the prevalence of autism is reported on a calendar-year basis. Our prevalence estimates were calculated by dividing the number of children identified with autism who lived in the surveillance region (e.g. Prince Edward Island) at any time during a given year by the total number of children who lived in that region in that year.
What age group is the 1 in 94 figure based on?
Since individuals with autism often are not diagnosed until they reach school age, the estimate above is based on children 6 to 9 years of age.
Why don’t you report the prevalence for 8-year-olds, like the Centers for Disease Control and Prevention does in the United States?
Our population in Canada is much smaller than that of the United States. We can get more reliable estimates by reporting the prevalence for an age group rather than a specific age.
Is the prevalence of autism increasing in Canada?
The prevalence of autism does appear to be increasing, based on the information we have collected since 2003. You can view a full report of our findings at www.nedsac.ca under Publications à Reports.
For more information, please contact:
Hélène Ouellette-Kuntz, PhD
NEDSAC Director and Associate Professor
Department of Community Health and Epidemiology, Queen’s University
Tel: 613-548-4417 x 1198