Research Spotlight: Study Estimates the Number of Canadians Living with Down Syndrome

Q: How would you summarize your study?

Official statistics on the number of individuals living with Down syndrome (DS) in Canada are currently unavailable. Prior to this study, various advocacy organizations reported widely varying population estimates. 

This study estimates an accurate number of babies born and people living with DS in Canada from 1950 to 2020.

Q: What question were you investigating?

In addition to estimating the total number of people living with DS in Canada from 1950 to 2020, we investigated the following:

• The estimated number of live births of children with DS in Canada from 1950 to 2020
• The impact of prenatal screening and subsequent elective terminations on the number of children with DS born in Canada
• How the prevalence of DS has changed in Canada over time
• How survival rates and, consequently, the age distribution of the DS population in Canada has changed over this period

Q: What methods or approach did you use?

We used a modeling method that combined information on how many babies in the general population were born each year, the ages of their mothers, information on the actual number of live births of babies with DS from birth defects surveillance programs, and information on how long people with DS typically lived. This helped us estimate the expected number of births of children with DS (absent selective terminations), the actual number of live births of children with DS, the impact of selective terminations, and the total population of people with DS over time. 

Q: What did you find?

We found prenatal screenings and elective terminations had a significant impact on DS births, resulting in 54% fewer children with DS being born in 2020 than potentially could have been born. Despite this, the total estimated number of people with DS living in Canada has increased substantially, from 5,138 in 1950 to 22,367 in 2020. This growth is largely attributed to improved survival rates, with the median life expectancy for people with DS rising from four years in 1950 to 59 years from 2000 onwards. This improvement has also changed the age distribution, with a growing proportion of people living into older adulthood.

Although the population is still increasing, its growth rate is slowing down, suggesting a potential decrease in the coming years. 

Q: What are the implications?

By providing these comprehensive estimates for Canada, our study contributes significantly to the understanding of the DS population dynamics in the country. The implications of this research are substantial and multifaceted, including informing policy and resource allocation, supporting advocacy efforts, understanding the impact of societal changes, highlighting the shift to an older population, forecasting future population trends, and providing international context.

Q: What are the next steps?

Earlier, we estimated the DS population in the United States, Europe, Australia, and New Zealand. Next, we will estimate the DS population in Latin American and Caribbean countries. By applying a similar methodology in other regions, we can help to create a more global picture of the DS population.