Plant-Based Dietary Index and Risk of Pancreatic Cancer: Findings from a Prospective Cohort Study

BACKGROUND: Data on the association between the plant-based diet and pancreatic cancer are sparse. We, therefore, examined associations for plant-based dietary indices (PDI), healthy PDI (hPDI), and unhealthy PDI (uPDI) with pancreatic cancer risk. METHODS: We used data from the Singapore Chinese Health Study, a prospective cohort study of 63,275 participants, ages 45 to 74 years, living in Singapore who were recruited during 1993 to 1998. The three plant-based dietary scores were calculated from the semiquantitative food frequency questionnaire that was collected at the baseline. We identified pancreatic cancer cases using record linkage with the Singapore Cancer Registry. A Cox proportional hazard regression method was used to generate HRs and 95% confidence intervals (CI) for pancreatic cancer in relation with PDI, hPDI, and uPDI scores, adjusted for potential confounders. RESULTS: After 17.6 years of follow-up, we identified 316 pancreatic cancer cases. uPDI was associated with increased risk of pancreatic cancer with a dose-response trend (HRper-SD increment = 1.20; 95% CI, 1.06-1.37). The adjusted HRs (95% CIs) for quartiles 2, 3, and 4 relative to quartile 1 of uPDI were 1.32 (0.94-1.86), 1.22 (0.86-1.71), and 1.68 (1.18-2.39), respectively (Ptrend = 0.01). Null association was found for PDI and hPDI with pancreatic cancer risk. CONCLUSIONS: We showed that uPDI was associated with increased risk of pancreatic cancer. IMPACT: Our results have public health implications for primary prevention against pancreatic cancer development, one of the deadliest malignancies worldwide.