Dietary gluten avoidance in Canada: a cross-sectional study using survey data

BACKGROUND: A gluten-free diet (GFD) is required for the management of some conditions, whereas some Canadians may follow a GFD for discretionary reasons. We sought to estimate the prevalence of Canadians who adhere to a GFD, identify factors associated with adherence to a GFD, and describe and compare the location of food preparation and consumption for those who follow a GFD, those who report no dietary avoidances and those reporting other dietary avoidances. METHODS: We used cross-sectional data from the 2015 Canadian Community Health Survey — Nutrition (n = 20 487). Demographic variables included sex, age group, ethnicity, highest level of household education and income adequacy. The relations between respondent characteristics and report of a GFD were estimated using logistic regression. Respondents were further categorized as avoiding dietary gluten, other dietary avoidances and no dietary avoidances. RESULTS: An estimated 1.9% of Canadians follow a GFD. Women had 2 times higher odds (odds ratio [OR] 2.08, 95% confidence interval [CI] 1.32 to 3.27) of reporting a GFD than men. After adjustment for income adequacy, household education, sex, age group and ethnicity, residents of Ontario and Quebec had about half the odds (OR 0.52, 95% CI 0.31 to 0.87, and OR 0.55, 95% CI 0.32 to 0.94, respectively) of reporting a GFD compared with residents of Atlantic Canada. Canadians who followed a GFD consumed significantly fewer calories from foods prepared at restaurants than both Canadians who reported no dietary avoidances and those who reported dietary avoidances other than gluten. Canadians following a GFD reported that 2.0% (95% CI 1.1% to 2.9%) of their daily kilocalories were from foods prepared at restaurants, compared with 6.7% (95% CI 5.4% to 7.9%) for Canadians reporting 1 or more dietary avoidances other than gluten, and 6.4% (95% CI 6.0% to 6.9%) for those reporting no avoidances. INTERPRETATION: The estimated 1.9% prevalence of dietary gluten avoidance likely includes individuals with celiac disease, wheat allergies and nonceliac gluten sensitivity, as well as individuals excluding gluten in the management of irritable bowel syndrome or for reasons related to dietary trends. Canadians eating GFDs consume fewer daily calories from restaurant-prepared foods than other Canadians, which may have social implications.