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

Wan X, presented a session held at the American Heart Association (AHA) from 16-18 November 2024, in Chicago, Illinois. This study explored the association between plant-based dietary patterns and all-cause and cause-specific mortality in patients with cardiovascular disease (CVD). Using the UK Biobank dataset, 10,841 participants with baseline CVD were followed over a median of 11.3 years. Three plant-based diet indexes were constructed from web-based 24-hour dietary recall questionnaires: an overall plant-based diet index (PDI), a healthy PDI (hPDI), and an unhealthy PDI (uPDI).

Participants were classified into tertiles based on adherence to PDI, hPDI, and uPDI. Mortality outcomes, including all-cause, CVD-specific, and cancer-specific deaths, were documented using the national death registry. Adjustments were made for potential confounders, including demographics, lifestyle factors, and clinical characteristics. 

During follow-up, 1,275 deaths were recorded. Higher adherence to PDI was negatively associated with all-cause mortality (HR_T3vsT1: 0.81, 95% CI: 0.70–0.94, Ptrend = 0.005) and CVD mortality (HR_T3vsT1: 0.78, 95% CI: 0.61–0.99, Ptrend = 0.040). Conversely, stronger adherence to uPDI was linked to increased all-cause mortality (HR_T3vsT1: 1.33, 95% CI: 1.16–1.53, Ptrend < 0.001) and both CVD and cancer mortality. Mediation analysis revealed that CRP levels explained 6.2%, 4.0%, and 5.1% of the relationship between uPDI and all-cause, CVD, and cancer mortality, respectively. No significant association was observed between hPDI and any mortality outcomes. 

The findings suggest that adherence to PDI reduces mortality risks, likely due to its emphasis on nutrient-dense, minimally processed plant foods. In contrast, the positive correlation between uPDI and mortality might result from the inflammatory impact of unhealthy plant-based foods, as indicated by elevated CRP levels. 

Among patients with CVD, adherence to PDI was associated with reduced risks of all-cause and CVD mortality, whereas uPDI was linked to higher mortality rates, mediated partly by CRP levels. These findings underscore the importance of promoting healthy plant-based dietary patterns and limiting the consumption of unhealthy plant-based foods in dietary guidelines.