Asthma prevalence in children 1 to 4 years of age, Canada, 2000/2001 to 2011/2012
![](https://cichprofile.ca/wp-content/uploads/2017/09/6.6.1_asthma_prevalence.png)
Source: CICH graphic created using data adapted from Public Health Agency of Canada, Canadian Chronic Disease Surveillance System 2000-2001 to 2010-2011, customized analyses.
Since the 1970s, there have been substantial increases in asthma prevalence in children of industrialized and non-industrialized countries.1
Statistics Canada confirmed a four-fold increase in childhood asthma over a 20-year period between 1978/79 and 1994/95.1
While some of this increase might be due to over-diagnosis, a number of international studies indicate a definite increase, with changes in the environment potentially contributing to this increase.1
According to the Canadian Chronic Disease Surveillance System, asthma prevalence in young children has been steadily declining since 2000 with 6.2% of children aged 1 to 4 having asthma in 2011/2012 compared to 10% in 2000/2001.
1Millar WJ, Hill GB. Childhood asthma. Health Reports (Statistics Canada, catalogue 82-003) 1998; 10(3): 9-21. http://www.statcan.gc.ca/pub/82-003-x/1998003/article/4137-eng.pdf– accessed March 15, 2017.