Objective: Dietary indexes measure the adherence of individuals to a set of nutritional recommendations. However, the health gains associated with adherence to various dietary indexes may vary. Our objective was to compare the magnitude of estimated avoided deaths by chronic diseases obtained by improving diet quality in the French population, measured by a variety of dietary indexes.
Design: Simulation study based on observational data.
Setting: Weighted data from a French population-based cohort study.
Participants: In participants from the NutriNet-Santé cohort, we computed dietary scores reflecting the adherence to various recommendations (Medi-Lite, Healthy Diet Indicator (HDI), Programme National Nutrition Santé/National Nutrition and Health Program - Guidelines Score, Diet Quality Index (DQI), Alternative Healthy Eating Index (AHEI) and the modified Food Standards Agency nutrient profiling system dietary index (FSAm-NPS DI)). Quintiles of the food groups' consumption and dietary intakes were used as input in a simulation model (Preventable Risk Integrated ModEl (PRIME)), yielding the number of delayed or avoided deaths in nutrition-related non-communicable diseases, comparing between very high or very low nutritional quality of the diet and medium nutritional quality.
Results: A modification of dietary intakes from medium quality to very low quality (i.e. from the middle quintile to the quintile with the lowest nutritional quality) was associated with an increased number of deaths ranging from 3485 (95 % uncertainty interval (CI) 4002, 2987) for HDI and 3379 (95 % CI 3881, 2894) for FSAm-NPS DI to 838 (95 % CI 1163, 523) for Medi-Lite. Conversely, a modification of dietary intakes from medium quality to very high quality was associated with a decrease in the number of deaths ranging from 1995 (95 % CI 1676, 2299) for Probability of Adequate Nutrient intake diet, 1986 (95 % CI 1565, 2361) for DQI-International, 1931 (95 % CI 1499, 2316) for FSAm-NPS DI and 858 (95 % CI 499, 1205) for HDI.
Conclusions: Our results provide some insights as the potential impact of following various dietary guidelines to reduce mortality from nutrition-related diseases.
Trial registration: ClinicalTrials.gov NCT03335644.
Keywords: Dietary index; Dietary recommendations; Mortality; Non-communicable diseases; Nutrient profile; Public health impact; Simulation study.