Abstract
BACKGROUND: Few studies have evaluated the effects of plant-based diets combined with ultra-processed food on cardiovascular diseases (CVD). The objective of this study was to assess associations between CVD risk and novel diet indices that integrate balance between plant-based and animal-based foods, nutritional quality and processing level. METHODS: We analyzed data from the French NutriNet-Santé prospective cohort. First, the two original healthy Plant-Based Diet and unhealthy Plant-Based Diet Indices (hPDI and uPDI) were computed. Four new indices were then built, based on the hPDI and uPDI computation, but with a multiplying factor to account for (i) the contribution of unprocessed food (UnPF) and (ii) the contribution of ultra-processed food (UPF), using the NOVA classification, culturally adapted. These two contributions (UnPF and UPF) were estimated using dietary data from 24 h records as percentages of total food consumed (g.day(-1)). The association between each of the six resulting index scores and cardiovascular disease (cerebrovascular and coronary) was estimated using multivariate Cox proportional hazards models adjusted for confounding factors. Sensitivity analyses were also performed to assess the robustness of these novel indices. FINDINGS: Among 63,835 participants, median follow-up time 9.0 years, IQR: 5-13 years, 76% women, mean age 51.4, SD = 10.2, no statistically significant protective or deleterious association was observed between those adhering to a nutritionally healthy but ultra-processed plant-based diet (hPDI-UPF), and a nutritionally unhealthy but unprocessed plant-based diet (uPDI-UnPF). When comparing participants with the highest adherence to a nutritionally healthy and unprocessed plant-based diet (hPDI-UnPF), to those with the lowest, we observed a 44% lower incidence of coronary heart disease (HR(D10 vs. D1): 0.56, 95% CI: [0.42-0.75]) and 32% lower risk for CVD (HR(D10 vs. D1): 0.68, 95% CI: [0.53-0.88]). Similarly, participants with the highest adherence to an unhealthy and ultra-processed plant-based diet (uPDI-UPF) had a 46% higher incidence of coronary heart disease (HR(D10 vs. D1): 1.46, 95% CI: [1.11-1.93]), and a 38% higher incidence of CVD (HR(D10 vs. D1): 1.38, 95% CI: [1.09-1.76]). This was the strongest association observed in our study. INTERPRETATION: The findings of this study mark the importance of considering not only balance between plant-based and animal-based foods, but also nutritional quality and degree of processing when evaluating association between diet and cardiovascular risk. FUNDING: French National Research Agency (ANR, ANR-22-CE36-0012).