Plant-Based Diet and the Risk of Cardiovascular Disease and Mortality: The Million Veteran Program

Abstract

Abstract Objectives Although prior studies have found inverse associations of plant-based diets with the risk of coronary heart disease, the results for stroke and total mortality are inconsistent. Little is known about the associations between a plant-based diet and cardiovascular health in US Veterans. We aim to prospectively examine the associations between the adherence to a plant-based diet and the incidence of myocardial infarction (MI), acute ischemic stroke (AIS) and total mortality. Methods We included 181,359 participants who were free of cardiovascular disease and cancer at baseline from the Million Veteran Program. Diet was assessed using a food frequency questionnaire at baseline. We calculated a plant-based diet index (PDI) by assigning positive scores to plant foods and reverse scores to animal foods. We calculated hazard ratios (HRs) and 95% confident intervals (CIs) by comparing participants in each quintile with those in the lowest quintile of the PDI. We used electronic health records to identify incident MI and AIS cases. Information on mortality was obtained from systematic searches of the National Death Index. Results Over 717,857 person-years of follow-up (mean follow-up: 4 years), we documented 1467 incident MI cases, 1253 AIS cases, and 5609 deaths. After adjustment for age, sex, body mass index (BMI), total energy intake, race/ethnicity, smoking, physical activity, alcohol use, educational level, socioeconomic status and baseline histories of diabetes, hypercholesterolemia and hypertension, a higher PDI was associated with significantly lower mortality (HR comparing extreme quintiles: 0.87, 95% CI: 0.78–0.96, Ptrend = 0.006). Participants with a greater adherence to a plant-based diet experienced lower risk of incident MI and AIS (HRs comparing extreme quintiles: 0.79, 95% CI: 0.64–0.97, Ptrend = 0.02 for MI; 0.69, 95% CI: 0.55–0.85, Ptrend = 0.005 for AIS). The associations of PDI with mortality, MI and AIS were consistent across different subgroups defined by sex, age, smoking, BMI, diabetes, hypertension and hypercholesterolemia, as well as between white and African American participants. Conclusions A greater adherence to a plant-based diet is associated with substantially lower risk of cardiovascular disease and total mortality in this large population of Veterans. Funding Sources US Department of Veterans Affairs.