What exactly is asthma, and why should we be concerned about it in the context of immigration?

Asthma is a chronic respiratory disease characterized by inflammation and narrowing of the airways. This is significant because it poses a substantial public health challenge, especially in countries like Canada with a diverse immigrant population and high asthma prevalence. Understanding how asthma incidence varies across immigrant generations can lead to better targeted prevention and public health strategies.

What is the 'healthy immigrant effect,' and how does it relate to asthma rates among new immigrants?

The 'healthy immigrant effect' is a phenomenon where newly arrived immigrants often exhibit better health outcomes, including lower asthma rates, compared to the native-born population. This could be due to healthier individuals self-selecting for migration, different lifestyle habits, or varying exposures in their countries of origin. However, this effect tends to diminish in subsequent generations, indicating the influence of the new environment.

Why do children of immigrants born in Canada have a higher risk of developing asthma?

Canadian-born children of immigrants display a significantly higher incidence of asthma compared to both their parents and children of long-term residents. This suggests that environmental factors within Canada play a crucial role in shaping asthma risk for subsequent generations. This highlights the need to examine and address specific environmental exposures impacting this group.

What specific environmental factors might be contributing to the increased asthma risk in Canadian-born children of immigrants?

Environmental exposures encountered early in life, potentially even in utero, are likely key factors contributing to the increased asthma risk among Canadian-born children of immigrants. These exposures can include things like air pollution, allergens, dietary changes, and altered microbial environments. The timing is critical because the developing immune system of infants and young children is particularly vulnerable to these environmental triggers.

How can we use the findings about asthma and immigrant generations to improve public health?

Understanding the generational shift in asthma risk allows interventions to be targeted to address the specific vulnerabilities of Canadian-born children of immigrants. Future research should pinpoint the precise environmental factors driving this increased risk. This knowledge will enable the development of tailored interventions to mitigate these exposures and promote respiratory health for all children.

Interplay of heritage and environment in asthma risk.

Asthma and Immigration: Unmasking the Generational Risk

Mira Elwood in Health & Wellness December 2025 • 4 min read.

"A deep dive into how asthma incidence shifts across immigrant generations in Canada, revealing surprising links to environmental factors and early life exposures."

Asthma, a chronic respiratory disease characterized by inflammation and narrowing of the airways, poses a significant public health challenge worldwide. In Canada, a country known for its high asthma prevalence and diverse immigrant population, understanding the interplay between immigration and asthma becomes crucial. Recent research sheds light on how asthma incidence varies across immigrant generations, revealing surprising patterns linked to environmental factors and early life exposures.

A new population-based cohort study, recently published, examined generational patterns of asthma incidence among immigrants in Canada over two decades. The study, which followed a large cohort of immigrants and their children, uncovered that while first-generation immigrants often experience lower asthma rates compared to long-term residents, their Canadian-born children face a significantly higher risk.

This article explores the key findings of this study, unraveling the complex relationship between immigration, environmental exposures, and asthma risk. By understanding these patterns, we can gain valuable insights into targeted prevention strategies and public health initiatives aimed at reducing the burden of asthma in Canada's diverse population.

The Generational Asthma Paradox: Understanding the Shifting Risks

Interplay of heritage and environment in asthma risk.

The study's findings highlight a fascinating paradox: first-generation immigrants, upon arrival in Canada, tend to have lower rates of asthma compared to the long-term Canadian population. This observation aligns with the "healthy immigrant effect," a phenomenon where newly arrived immigrants often exhibit better health outcomes than the native-born population. This advantage could be attributed to various factors, including self-selection of healthier individuals for migration, different lifestyle habits, or varying exposures in their countries of origin.

However, the study revealed a concerning trend: the children of immigrants born in Canada displayed a significantly higher incidence of asthma compared to both their parents and the children of long-term residents. This suggests that factors within the Canadian environment play a crucial role in shaping asthma risk for subsequent generations.

Lower Initial Risk: Immigrants often arrive with a lower asthma incidence.
Rising Risk in Children: Canadian-born children of immigrants see a higher asthma incidence.
Environmental Influence: Canadian environment and lifestyle are key contributing factors.

The increased asthma risk among Canadian-born children of immigrants points towards the influence of environmental exposures encountered early in life, even in utero. These exposures can include a range of factors, from air pollution and allergens to dietary changes and altered microbial environments. The timing of exposure appears critical, suggesting that the developing immune system of infants and young children may be particularly vulnerable to these environmental triggers.

Implications for Prevention and Public Health

The findings from this study offer valuable insights for asthma prevention and public health strategies in Canada. By understanding the generational shift in asthma risk, interventions can be targeted to address the specific vulnerabilities of Canadian-born children of immigrants. Future research should focus on identifying the precise environmental factors driving this increased risk, allowing for the development of tailored interventions to mitigate these exposures and promote respiratory health for all children in Canada.