Abstract 7383: Plant-based diet index and risk of hepatocellular carcinoma: Findings from a prospective cohort study

Abstract Background: Hepatocellular carcinoma (HCC) accounts for ∼90% of primary liver cancer cases, one of leading causes for cancer incidence (>900, 000 new cases/year) and mortality (>800, 000 deaths/year) worldwide. The established risk factors for HCC are chronic infection with hepatitis B virus (HBV), hepatitis C virus (HCV), alcohol abuse and obesity; among which about two-thirds of HCC cases are attributable to viral hepatitis. Recently, plant-based diets, including overall plant-based dietary index (PDI) and healthful plant-based dietary index (hPDI), which were based on overall intake and sub-categories of food items that deem to be “healthfulness” to better account for the quality of plant foods, have received a great attention due to their potential benefits to chronic diseases. Data on the association between PDI and risk of HCC are sparse. We, thus, prospectively evaluated the associations between PDI and hPDI scores and HCC risk. Methods: We used data from the Singapore Chinese Health Study, a prospective cohort study of 63, 275 participants aged 45-74 living in Singapore. Both PDI and hPDI scores were derived from the semi-quantitative food frequency questionnaire at baseline. The HCC incident cases were identified through record linkage analysis with the Singapore Cancer Registry. Cox proportional hazard regression method was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for HCC in relation with PDI and hPDI scores. A nested case-control study (197 HCC incident cases and 465 matched controls) was also performed among the cohort participants. Conditional logistic regression model was used for the case-control analysis to examine the association between PDI and hPDI scores with risk of HCC with further adjustment for HBsAg seropositivity status. Results: After 17.6 years of follow-up with 819, 573 person-years, we identified 561 incident HCC cases. We found an inverse association between PDI and HCC risk (HRper-SD increment=0.87, 95% CI: 0.79-0.95; Ptrend=0.009). Compared with the lowest quartile, the HRs (95% CIs) of HCC for quartiles 2, 3, and 4 of PDI score were 0.81 (0.64-1.01), 0.75 (0.59-0.95), and 0.73 (0.56-0.93), respectively. Similar pattern was also found between hPDI and HCC risk (HRper-SD increment=0.86, 95% CI: 0.79-0.94; Ptrend=0.002). Furthermore, this inverse association pattern between PDI and HCC risk was found only in HBsAg-negative individuals in the case-control study (ORper-SD increment=0.79, 95% CI: 0.64-0.98; Ptrend =0.04). Conclusions: Our findings showed that higher plant-based dietary index score was associated with lower risk of HCC. Our findings have public health implications for primary prevention against the development of HCC, particularly relevant in populations such as the United States where HCC incidence rate has been increasing in the past 3 decades dur to high prevalence of obesity, but not due to HBV and/or HCV infection. Citation Format: Yen Thi-Hai Pham, Renwei Wang, Jaideep Behari, Jian-Min Yuan, Hung N. Luu. Plant-based diet index and risk of hepatocellular carcinoma: Findings from a prospective cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7383.