Abstract Body (Do not enter title and authors here): Background and Aims:
Plant-based diets have been associated with a lower risk of total mortality among generally health populations. However, the associations of plant-based diets with total mortality remain unclear among older people with cardiometabolic diseases, who have an elevated risk of mortality.

Methods:
We prospectively followed 4,485 participants (mean age: 84 years) from the China Prospective Longitudinal Survey of Health and Longevity (2006-2018), who had cardiometabolic disease in 2006. Dietary data were collected at baseline using a food-frequency questionnaire. Using these data, we created an overall plant-based diet index (PDI), in which plant-based foods received positive scores while animal foods (meat, fish and aquatic products, eggs, milk, animal fats) received reversed scores accordingly. We also created a healthful plant-based diet index (hPDI), where healthy plant-based foods (whole grains, vegetables, vegetable oils, fresh fruits, legumes, beans, garlic, nuts, tea) received positive scores, while less healthy plant-based foods (refined grains, pickles, sugar, preserved vegetables) and animal-based foods were given reversed scores. In addition, an unhealthful plant-based diet index (uPDI) was created by assigning positive scores to less healthy plant-based foods while reverse scores to healthy plant-based foods and animal-based foods. We used Cox proportional hazards regression to compute hazard ratios (HRs) and 95% CIs for total mortality, with adjustment for demographics, dietary and lifestyle factors, and medical history.

Results:
During a 12 years of follow-up, 2,881 deaths were recorded. A higher score from PDI and hPDI was associated with a lower risk total mortality among participants with cardiometabolic diseases (HR and 95% CI for extreme quintiles of PDIs: 0.85, 95% CI 0.75–0.96, P_trend < 0.001; hPDI: 0.84 (0.74–0.94), P_trend < 0.001). A higher uPDI score was associated with a higher total mortality among participants with cardiometabolic diseases (uPDI: 1.28 (1.13-1.47), P_trend < 0.001). These results were consistent in subgroup analyses by age, sex, smoking status, alcohol consumption, education level, physical activity, and BMI.
Conclusion:
Our study suggests that among older Chinese participants with cardiometabolic diseases, adherence to an overall plant-based diet or a healthful plant-based diet, is associated with a lower total mortality, while an unhealthful plant-based diet was associated with a higher total mortality.