Association between household food insecurity and mortality in Canada: a population-based retrospective cohort study

BACKGROUND: Food insecurity affects 1 in 8 households in Canada, with serious health consequences. We investigated the association between household food insecurity and all-cause and cause-specific mortality. METHODS: We assessed the food insecurity status of Canadian adults using the Canadian Community Health Survey 2005-2017 and identified premature deaths among the survey respondents using the Canadian Vital Statistics Database 2005-2017. Applying Cox survival analyses to the linked data sets, we compared adults' all-cause and cause-specific mortality hazard by their household food insecurity status. RESULTS: Of the 510 010 adults sampled (3 390 500 person-years), 25 460 died prematurely by 2017. Death rates of food-secure adults and their counterparts experiencing marginal, moderate and severe food insecurity were 736, 752, 834 and 1124 per 100 000 person-years, respectively. The adjusted hazard ratios (HRs) of all-cause premature mortality for marginal, moderate and severe food insecurity were 1.10 (95% confidence interval [CI] 1.03-1.18), 1.11 (95% CI 1.05-1.18) and 1.37 (95% CI 1.27-1.47), respectively. Among adults who died prematurely, those experiencing severe food insecurity died on average 9 years earlier than their food-secure counterparts (age 59.5 v. 68.9 yr). Severe food insecurity was consistently associated with higher mortality across all causes of death except cancers; the association was particularly pronounced for infectious-parasitic diseases (adjusted HR 2.24, 95% CI 1.42-3.55), unintentional injuries (adjusted HR 2.69, 95% CI 2.04-3.56) and suicides (adjusted HR 2.21, 95% CI 1.50-3.24). INTERPRETATION: Canadian adults from food-insecure households were more likely to die prematurely than their food-secure counterparts. Efforts to reduce premature mortality should consider food insecurity as a relevant social determinant.