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Abstract
Objectives Coeliac disease (CD) is a complex autoimmune disorder with known genetic risk factors. Approximately 1% of individuals of European ancestry have CD, but the prevalence among different ethnicities living in Canada remains unknown. The objective of the present study was to determine the prevalence of positive CD serology in a population of Canadian adults living in Toronto, and to determine whether the prevalence of CD seropositivity and predisposing human leucocyte antigen (HLA)-DQ2/DQ8 risk genotypes differ between major ethnocultural groups.
Design Cross-sectional screening study of participants from the Toronto Nutrigenomics and Health and the Toronto Healthy Diet studies.
Setting University campus and households across Toronto, Canada.
Participants: free-living Adults (n=2832) of diverse ethnocultural backgrounds.
Main outcome measures Prevalence of positive CD serology was determined by screening for antitissue transglutaminase antibodies in individuals with predisposing HLA-DQ2/DQ8 genotypes. HLA genotypes were determined using six single nucleotide polymorphisms in the HLA gene region.
Results Of the 2832 individuals screened, a total of 25 (0.88%; 95% CI 0.57% to 1.30%) were determined to have positive CD serology. The majority of seropositive CD cases were undiagnosed (87%). Prevalence was highest among Caucasians (1.48%; 95% CI 0.93% to 2.23%), and similar in those of ‘Other’ (0.74%; 95% CI 0.09% to 2.63%) or ‘Unknown’ (0.43; 95% CI 0.01% to 2.36%) ethnicity. No cases of positive CD serology were identified among East Asian or South Asian individuals. East Asians had a lower prevalence of HLA risk genotypes than Caucasians and South Asians (p<0.005).
Conclusions The prevalence of positive CD serology among Canadian adults living in Toronto is likely ~1%, with 87% of cases being undiagnosed. These findings suggest the need for better screening in high genetic risk groups.
Trial registration number NCT00516620; Post-results.
- Epidemiology
- Adult Gastroenterology
- Coeliac Disease
- Genetics
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Footnotes
Contributors JJ and AE-S designed the study. AE-S and DJAJ secured funding. JJ, CRV and SBD performed the analyses. JJ analysed the data and wrote the initial draft. All authors reviewed the manuscript. AE-S had primary responsibility for final content.
Funding This work was supported by the Canadian Institutes of Health Research. JJ is a recipient of a Canadian Institutes of Health Research Doctoral Research Award.
Competing interests AE-S holds shares in Nutrigenomix, a genetic testing company for personalised nutrition. DJAJ has received research grants from Saskatchewan Pulse Growers, the Agricultural Bioproducts Innovation Program through the Pulse Research Network, the Advanced Foods and Material Network, Loblaw Companies, Unilever, Barilla, the Almond Board of California, Agriculture and Agri-Food Canada, Pulse Canada, Kellogg’s Company, Canada, Quaker Oats, Canada, Procter & Gamble Technical Centre, Bayer Consumer Care, Springfield, NJ, Pepsi/Quaker, International Nut & Dried Fruit (INC), Soy Foods Association of North America, the Coca Cola Company (investigator-initiated, unrestricted grant), Solae, Hain Celestial, the Sanitarium Company, Orafti, the International Tree Nut Council Nutrition Research and Education Foundation, the Peanut Institute, the Canola and Flax Councils of Canada, the Calorie Control Council (CCC), the CIHR, the Canada Foundation for Innovation, and the Ontario Research Fund. He has been on the speaker’s panel, served on the scientific advisory board and/or received travel support and/or honoraria from the Almond Board of California, Canadian Agriculture Policy Institute, Loblaw Companies, Nutrigenomix, the Griffin Hospital (for the development of the NuVal scoring system), the Coca Cola Company, EPICURE, Danone, Saskatchewan Pulse Growers, Sanitarium Company, Orafti, the Almond Board of California, the American Peanut Council, the International Tree Nut Council Nutrition Research and Education Foundation, the Peanut Institute, Herbalife International, Pacific Health Laboratories, Nutritional Fundamental for Health, Barilla, Metagenics, Bayer Consumer Care, Unilever Canada and Netherlands, Solae, Kellogg, Quaker Oats, Procter & Gamble, the Coca Cola Company, the Griffin Hospital, Abbott Laboratories, the Canola Council of Canada, Dean Foods, the California Strawberry Commission, Hain Celestial, PepsiCo, the Alpro Foundation, Pioneer Hi-Bred International, DuPont Nutrition and Health, Spherix Consulting and WhiteWave Foods, the Advanced Foods and Material Network, the Canola and Flax Councils of Canada, the Nutritional Fundamentals for Health, Agriculture and Agri-Food Canada, the Canadian Agri-Food Policy Institute, Pulse Canada, the Saskatchewan Pulse Growers, the Soy Foods Association of North America, the Nutrition Foundation of Italy (NFI), Nutrasource Diagnostics, the McDougall Program, the Toronto Knowledge Translation Group (St Michael’s 344 Hospital), the Canadian College of Naturopathic Medicine, The Hospital for Sick Children, the Canadian Nutrition Society (CNS), the American Society of Nutrition (ASN), Arizona State University, Paolo Sorbini Foundation, and the Institute of Nutrition, Metabolism and Diabetes. He received an honorarium from the US Department of Agriculture to present the 2013 W O Atwater Memorial Lecture. He received the 2013 Award for Excellence in Research from the International Nut and Dried Fruit Council. He received funding and travel support from the Canadian Society of Endocrinology and Metabolism to produce mini cases for the Canadian Diabetes Association (CDA). He is a member of the International Carbohydrate Quality 352 Consortium (ICQC). His wife, ALJ, is a director and partner of Glycemic Index Laboratories, and his sister received funding through a grant from the St Michael’s Hospital Foundation 354 to develop a cookbook for one of his studies. JJ, CRV and SBD have no conflicts of interest to declare.
Ethics approval Research Ethics Boards at the University of Toronto and St Michael’s Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data will be made available to all interested researchers upon request to the corresponding author.