Estimation of the number of people with Down syndrome living in Canada.

Abstract

We estimate the live births (LBs), selective terminations, miscarriages, and overall population with Down syndrome (DS) in Canada from 1950 to 2020. This study adds to previous work from the United States, Europe, Australia, and New Zealand. The LBs with DS-in the absence of DS-related terminations-were estimated on the maternal age distribution in the general population. Actual LBs were modeled on registry data. We applied constructed survival curves to annual LBs to estimate population numbers. In 2020, there were an estimated 418 LBs with DS in Canada. As a result of DS-related elective terminations, there were 54% fewer children with DS born than potentially could have been born in Canada, as of 2020. The estimated number of people with DS in Canada has increased from 5138 people in 1950 to 22,367 in 2020. Although, in recent years, the population size of people with DS is decreasing in Australia, New Zealand, and Europe, the number of people with DS is still growing in the United States and Canada. In Canada, however, the growth rate is increasingly slowing down, probably foreshadowing a population contraction in the coming years.