Asthma, type 1 and type 2 diabetes mellitus, and inflammatory bowel disease amongst South Asian immigrants to Canada and their children: a population-based cohort study

Eric I Benchimol; Douglas G Manuel; Teresa To; David R Mack; Geoffrey C Nguyen; Jennifer L Gommerman; Kenneth Croitoru; Nassim Mojaverian; Xuesong Wang; Pauline Quach; Astrid Guttmann

doi:10.1371/journal.pone.0123599

Asthma, type 1 and type 2 diabetes mellitus, and inflammatory bowel disease amongst South Asian immigrants to Canada and their children: a population-based cohort study

PLoS One. 2015 Apr 7;10(4):e0123599. doi: 10.1371/journal.pone.0123599. eCollection 2015.

Authors

Affiliations

¹ Children's Hospital of Eastern Ontario Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Eastern Ontario, Ottawa, Canada; Department of Pediatrics, University of Ottawa, Ottawa, Canada; School of Epidemiology, Public Health and Preventative Medicine, University of Ottawa, Ottawa, Canada; Institute for Clinical Evaluative Sciences, Toronto, Canada.
² Department of Family Medicine, University of Ottawa, Ottawa, Canada; Institute for Clinical Evaluative Sciences, Toronto, Canada; Ottawa Hospital Research Institute, Ottawa, Canada.
³ Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Canada; Department of Immunology, University of Toronto, Toronto, Canada.
⁴ Children's Hospital of Eastern Ontario Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Eastern Ontario, Ottawa, Canada; Department of Pediatrics, University of Ottawa, Ottawa, Canada.
⁵ Institute for Clinical Evaluative Sciences, Toronto, Canada; Mount Sinai Centre for Inflammatory Bowel Disease, Toronto, Canada; Department of Medicine, University of Toronto, Toronto, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada.
⁶ Department of Immunology, University of Toronto, Toronto, Canada.
⁷ Mount Sinai Centre for Inflammatory Bowel Disease, Toronto, Canada; Department of Medicine, University of Toronto, Toronto, Canada.
⁸ Institute for Clinical Evaluative Sciences, Toronto, Canada.
⁹ Children's Hospital of Eastern Ontario Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Eastern Ontario, Ottawa, Canada; Institute for Clinical Evaluative Sciences, Toronto, Canada.
¹⁰ Institute for Clinical Evaluative Sciences, Toronto, Canada; Division of Pediatric Medicine, The Hospital for Sick Children, Toronto, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada; Department of Paediatrics, University of Toronto, Toronto, Canada.

Abstract

Background: There is a high and rising rate of immune-mediated diseases in the Western world. Immigrants from South Asia have been reported to be at higher risk upon arrival to the West. We determined the risk of immune-mediated diseases in South Asian and other immigrants to Ontario, Canada, and their Ontario-born children.

Methods: Population-based cohorts of patients with asthma, type 1 diabetes (T1DM), type 2 diabetes (T2DM), and inflammatory bowel disease (IBD) were derived from health administrative data. We determined the standardized incidence, and the adjusted risk of these diseases in immigrants from South Asia, immigrants from other regions, compared with non-immigrant residents of Ontario. The risk of these diseases in the Ontario-born children of immigrants were compared to the children of non-immigrants.

Results: Compared to non-immigrants, adults from South Asia had higher risk of asthma (IRR 1.56, 95%CI 1.51-1.61) and T2DM (IRR 2.59, 95%CI 2.53-2.65). Adults from South Asia had lower incidence of IBD than non-immigrants (IRR 0.32, 95%CI 0.22-0.49), as did immigrants from other regions (IRR 0.29, 95%CI 0.20-0.42). Compared to non-immigrant children, the incidence of asthma (IRR 0.66, 95%CI 0.62-0.71) and IBD (IRR 0.47, 95%CI 0.33-0.67) was low amongst immigrant children from South Asia. However, the risk in Ontario-born children of South Asian immigrants relative to the children of non-immigrants was higher for asthma (IRR 1.75, 95%CI 1.69-1.81) and less attenuated for IBD (IRR 0.90, 95%CI 0.65-1.22).

Conclusion: Early-life environmental exposures may trigger a genetic predisposition to the development of asthma and IBD in South Asian immigrants and their Canada-born children.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Asia / epidemiology
Asian People
Asthma / epidemiology*
Diabetes Mellitus, Type 1 / epidemiology*
Diabetes Mellitus, Type 2 / epidemiology*
Emigrants and Immigrants / statistics & numerical data*
Female
Humans
Incidence
Inflammatory Bowel Diseases / epidemiology*
Male
Middle Aged
Ontario / epidemiology
Retrospective Studies
Risk Factors
Young Adult

Grants and funding

Funding from: (1) Ontario Ministry of Health and Long-Term Care Academic Health Sciences Centre Alternate Funding Plan Innovation Fund. The funders had no role in the study design or conduct, interpretation of the results, or authorship of the manuscript. Researchers were considered independent from the funders. (2) Faculty of Medicine, University of Toronto. The funders had no role in the study design or conduct, interpretation of the results, or authorship of the manuscript. Researchers were considered independent from the funders.