Baden MY, Liu G, Satija A, et al. - Experts examined the relationship between 12-year changes in plant-based diet quality evaluated by three plant-based diet indices—an overall plant-based diet index (PDI), a healthful PDI (hPDI), and an unhealthful PDI (uPDI)—and subsequent total and cause-specific mortality in 49,407 and 25,907 women in the Nurses' Health Study and men in the Health Professionals Follow-Up Study, respectively, who were free from cardiovascular disease (CVD) and cancer in 1998. For CVD mortality, the risk correlated with a 10-point rise in each plant-based diet index was 7%, 9%, and 8% lower for PDI, lower for hPDI, and higher for uPDI, respectively. No consistent correlations between variations in plant-based diet indices and cancer mortality were noted. Hence, improving plant-based diet quality over a 12-year period was related to a lower risk of total and CVD mortality, whereas elevated intake of an unhealthful plant-based diet was correlated with a greater risk of total and CVD mortality.