Classification differences in food insecurity measures between the US and Canada: practical implications to trend monitoring and health research

Background: Food insecurity, the inadequate access to food due to financial constraints, is a major public health issue in the US and Canada, where the same 18-item questionnaire is used to monitor food insecurity. Researchers often assume that findings on food insecurity from the two countries are comparable to each other, but there are between-country differences in how food insecurity status is determined. Objectives: We aimed to compare the distribution of household food insecurity in the Canadian population applying the US and Canadian classification schemes. We also examined the extent to which associations between food insecurity and adults’ health differ under the two schemes. Methods: We used the population representative Canadian Community Health Survey 2005-2017 linked to administrative health records. Food insecurity was measured by the Household Food Security Survey Module. Adults 18 years and older with valid food insecurity status were included from all jurisdictions except Quebec (n = 403,200). We cross-tabulated food insecurity status classified by the US and Canadian schemes. We also fitted logistic regressions on self-reported and objective health measures adjusting for confounders. Results: Applying the Canadian classification scheme, 7.7 percent of households were food insecure; the number fell to 6.0 percent with the US scheme. Associations between food insecurity status and health measures were mostly similar across classification schemes, though the associations between food insecurity and self-reported health were slightly larger if the US scheme was applied. Marginal food security/insecurity was associated with worse health measures irrespective of the classification scheme. US-Canada discordance in classification of marginal food security/insecurity had limited effect on health prediction. Conclusions: US-Canada differences in classification impacted the apparent distribution of household food insecurity but not the associations between food insecurity and measures of adult health. Marginal food security/insecurity should be set apart from the food-secure group for trend monitoring and health research.