Dietary Patterns Attributable Mortality and Life Expectancy Lost in Canada: Evidence from Canadian National Nutrition Survey Linked to Routinely-Collected Health Administrative Databases

Am J Epidemiol. 2022 Oct 26;kwac189. doi: 10.1093/aje/kwac189. Online ahead of print.


Using five diet quality indices, we estimated the poor dietary pattern attributable mortality and life expectancy lost at the national level, which had previously been largely unknown. The Canadian Community Health Survey 2004 linked to vital statistics was used (n=16 212 adults; representing n=22 898 880). After a median follow-up of 7.5 years, 1722 mortality cases were recorded. Population attributable fractions were calculated to estimate mortality burden of poor dietary patterns (Dietary Guidelines for Americans Adherence Index 2015, Dietary Approaches to Stop Hypertension, Healthy Eating Index, Alternative HEI, and Mediterranean Style Dietary Pattern Score). Better diet quality was associated with a 32-51% and 21-43% reduction in all-cause mortality among adults 45-80 years and ≥20 years, respectively. Projected life expectancy at 45 years was longer for Canadians adhering to a healthy dietary pattern (average 5.2-8.0 years (males) and 1.6-4.1 (females)). At the population level, 26.5-38.9% (males) and 8.9-22.9% (females) of deaths were attributable to poor dietary patterns. Survival benefit was greater for individuals with higher scores on all diet indices, even with relatively small intake differences. The large attributable burden was likely from assessing overall dietary patterns instead of a limited range of foods and nutrients.

Keywords: diet quality indices; dietary pattern; epidemiology; mortality; nutrition; prospective cohort studies.