Plant-based diet indices and the risk of chronic kidney disease, cardiovascular morbidity and mortality in American adults

Plant-based diets are dietary patterns that emphasize higher intakes of plant foods and are low in animal foods. Recently, several distinct plant-based diet indices have been designed to characterize adherence to plant-based diets. Using plant-based diet indices, this dissertation prospectively investigated the association between plant-based diets and chronic kidney disease,cardiovascular disease, cardiovascular disease mortality, and all-cause mortality in a community-based cohort. In addition, all available plant-based diet indices were compared by assessing if greater adherence is associated with a lower risk of hypertension. Using dietary data captured by food frequency questionnaires in the Atherosclerosis Risk in Communities (ARIC) study (45-64 years), 4 indices were constructed: “an overall lantbased diet index (PDI),” “a healthy plant-based diet index (hPDI),” “a less healthy (unhealthy) plant-based diet index (uPDI),” and a “provegetarian diet index.” In PDI, all plant foods were positively scored; in hPDI, only plant foods identified as healthful were positively scored. In uPDI, only plant foods identified as less healthful were positively scored. In provegetarian diet, selected plant foods were positively scored. All indices negatively scored animal foods. Using Cox proportional hazards models, greater adherence to hPDI and provegetarian diet was associated with a lower risk of chronic kidney disease. Greater adherence to PDI and provegetarian diet was associated with a lower risk of cardiovascular disease, cardiovascular disease mortality, and all-cause mortality. The hPDI was associated with a lower risk of cardiovascular disease mortality and all-cause mortality. The uPDI was associated with a higher risk of chronic kidney disease, but did not show an association with cardiovascular disease. When we compared all indices, most indices captured similar dietary patterns. However, differences existed in how food groups were scored. Greater adherence to most indices was associated with a lower risk of hypertension, but uPDI was associated with a higher risk. No significant association was observed with one diet index. These findings illustrate that how plant-based diets are operationalized can affect the ability to detect an association between plant-based diets and chronic diseases. Findings from this dissertation add to the literature that plant-based diets may be considered for prevention of chronic diseases