Plant-Based Diet Indices with Greenhouse Gas Emissions and Risk of Cardiometabolic Diseases and All-Cause Mortality: Longitudinal China Cohort Study

<b>Background</b>: Environmental and cardiometabolic impacts of adherence to plant-based dietary patterns with different quality are unclear. <b>Objectives:</b> To investigate the associations between adherence to the overall, healthy, and unhealthy plant-based dietary patterns, as assessed by the plant-based diet index (PDI), healthy PDI (hPDI), and unhealthy PDI (uPDI), respectively, and risk of myocardial infarction (MI), type 2 diabetes (T2D), stroke, and all-cause mortality and greenhouse gas (GHG) emissions. <b>Methods</b>: Data from adults (N = 14,652 for cardiometabolic diseases and 15,318 for all-cause mortality) in the China Health and Nutrition Survey (1997-2015 wave) were analyzed. PDI, hPDI, and uPDI scores were calculated with dietary intake data. The total GHG emissions were calculated by summing the amount of emissions from all food groups included in the index. Cox proportional hazard regression models and linear regression models were used for statistical analysis. <b>Results</b>: Greater adherence to an unhealthy plant-based dietary pattern, as reflected by higher uPDI scores, was positively associated with risk of MI (Q5 vs. Q1: HR = 5.90; 95% CI: 2.59-13.48), T2D (Q5 vs. Q1: HR = 2.18; 95% CI: 1.75-2.73), stroke (Q5 vs. Q1: HR = 5.96; 95% CI: 2.86-12.42) and all-cause mortality (Q5 vs. Q1: HR = 6.87; 95% CI: 4.70-10.03). PDI scores were inversely associated with the risk of MI, T2D, and all-cause mortality, and hPDI scores were inversely and positively associated with the risk of T2D and stroke, respectively. All scores were inversely associated with GHG emissions (all <i>p</i>-trends < 0.001). <b>Conclusions</b>: Long-term adherence to unhealthy plant-based dietary patterns guided by higher uPDI scores may be a risk factor for new-onset cardiometabolic diseases and all-cause death in Chinese adults. Food-based dietary guidelines, clinicians, and dietitians should consider the quality of plant-based dietary patterns prior to making recommendations for both healthy individuals and those with elevated cardiometabolic disease risk.