Plant-based diet quality and all-cause mortality in a high-risk population

Abstract Background Individuals with chronic conditions such as cardiovascular disease (CVD), type 2 diabetes, and cancer are considered high-risk populations due to their elevated risk of morbidity and mortality. Plant-based diets have gained attention for their potential role in disease prevention and management in general population; however, their relationship with mortality outcomes in high-risk populations remains underexplored. Methods We analyzed data from the Moli-sani Study, a prospective cohort of men and women aged ≥35 years enrolled in Italy (2005-2010). A total of 2,897 participants with a history of CVD, type 2 diabetes, or cancer at baseline were classified at high-risk. Dietary intake was assessed by a validated FFQ. The quality of the plant-based diet was assessed using three distinct dietary patterns: an overall pro-vegetarian food pattern (PVG0), a whole plant-based food pattern (PVG1, including e.g. fruits, vegetables, and nuts), and a pattern mainly focused on processed plant-based foods (PVG2, e.g. fruit juices, refined grains, and sugar-sweetened beverages). Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality, adjusting for confounders. Results Over a median follow up of 14.4 years, a total of 1,137 deaths occurred. Multivariable-adjusted HRs for all-cause mortality (1-SD increase) associated with PVG0, PVG1 and PVG2 dietary patterns were 0.92 (95%CI 0.86-0.98), 0.88 (95%CI 0.83-0.94), and 1.12 (95%CI 1.06-1.20), respectively. Conclusions In high-risk individuals, greater adherence to plant-based diets mainly including whole plant foods was associated with lower mortality, while plant-based diets rich in refined carbohydrates or processed plant-based foods were associated with a higher risk. These findings support dietary strategies focused on whole plant foods as a key component of chronic disease management and secondary prevention in high-risk populations. Key messages • Whole food plant-based diets, but not processed plant-based diets, are associated with lower mortality in high-risk individuals. • Plant food quality may be critical in disease management.