title: 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.
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).
  
  
  CONCLUSIONS
  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.
authors: 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.
authors: Eric I
authors: EI
authors: Benchimol
authors: Department of Family Medicine, University of Ottawa, Ottawa, Canada; Institute for Clinical Evaluative Sciences, Toronto, Canada; Ottawa Hospital Research Institute, Ottawa, Canada.
authors: Douglas G
authors: DG
authors: Manuel
authors: 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.
authors: Teresa
authors: T
authors: To
authors: 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.
authors: David R
authors: DR
authors: Mack
authors: 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.
authors: Geoffrey C
authors: GC
authors: Nguyen
authors: Department of Immunology, University of Toronto, Toronto, Canada.
authors: Jennifer L
authors: JL
authors: Gommerman
authors: Mount Sinai Centre for Inflammatory Bowel Disease, Toronto, Canada; Department of Medicine, University of Toronto, Toronto, Canada.
authors: Kenneth
authors: K
authors: Croitoru
authors: Institute for Clinical Evaluative Sciences, Toronto, Canada.
authors: Nassim
authors: N
authors: Mojaverian
authors: Institute for Clinical Evaluative Sciences, Toronto, Canada.
authors: Xuesong
authors: X
authors: Wang
authors: 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.
authors: Pauline
authors: P
authors: Quach
authors: 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.
authors: Astrid
authors: A
authors: Guttmann
mesh_terms: D000293:Adolescent; D000328:Adult; D001208:Asia / Q000453:epidemiology; D044466:Asian People; D001249:Asthma / Q000453:epidemiology*; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult