Plant-Based Diet and All-Cause and Cause-Specific Mortality among Patients with Cardiovascular Disease: A Population-Based Cohort Study

The role of plant-based diets in preventing premature death among patients with cardiovascular disease (CVD) has remained unknown. We aim to explore the association of plant-based dietary patterns with all-cause and cause-specific mortality among patients with CVD. A total of 10 824 participants with CVD at the baseline were followed up in the UK Biobank. We constructed three types of plant-based diet indexes [an overall plant-based diet index (PDI), a healthful PDI (hPDI), and an unhealthful PDI (uPDI)] by assigning different weights to various food groups from web-based 24 h dietary recall questionnaires. The national death registry documented the primary causes of death. The Cox proportional hazards regression models were utilized to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality. Over a median of 9.5 years follow-up, 1273 death cases were ascertained. After multivariable adjustment, PDI had an inverse correlation with all-cause mortality [HRT3 vs. T1: 0.81 (0.70-0.94), Ptrend = 0.005] and marginal inverse association with CVD mortality [HRT3 vs. T1: 0.78 (0.61-0.99), Ptrend = 0.038], while uPDI displayed a positive correlation with all-cause mortality [HRT3 vs. T1: 1.33 (1.16-1.53), Ptrend < 0.001], CVD, and cancer mortality. Additionally, in mediation analyses, serum concentration of C-reactive protein (CRP) accounted for 6.2%, 4.0%, and 5.1% of the relationship between uPDI and all-cause, CVD, and cancer mortality, respectively. No significant associations were detected between hPDI and mortality. Our findings support dietary guidelines that recommend limiting the consumption of unhealthy plant-based foods.