Dietary Patterns and Risk of Pancreatic Cancer: A Systematic Review
Authors: Zheng Jiali , Guinter Mark , Merchant Anwar , Wirth Michael , Zhang Jiajia , Stolzenberg‐Solomon Rachael , Steck Susan 
Published: November 2023

BackgroundPancreatic cancer (PanC) has the highest case‐fatality rate among major cancers. Identifying modifiable risk factors, such as dietary patterns, is important toward reducing the burden of this disease. Our goal was to conduct a systematic review to summarize the association between dietary patterns and PanC risk.MethodLiterature search performed by two reviewers was restricted to case‐control and cohort studies identified from PubMed or Web of Science as of June 2016. Eligible studies included a dietary pattern (a priori or data‐driven) as the exposure and reported PanC incidence or mortality as outcome with reported odds ratio (OR), hazard ratio (HR), or relative risk (RR) as an estimate of association and corresponding standard error or 95% confidence interval (CI). For each study, information was extracted and presented on study characteristics, the diet assessment tool, food or nutrient components included in each data‐driven dietary pattern or scoring algorithm for each a priori dietary pattern, and estimates of association with 95% CI for the highest versus the lowest category of dietary pattern score in the multivariate model. Forest plots were used to graphically represent the sex‐specific and overall associations of each identified dietary pattern.ResultsA total of 16 eligible studies with 1,848,584 subjects aged from 18 to 94 years old and 8,881 PanC cases were identified. Eight studies (3 case‐control and 5 cohort studies) examined a priori dietary patterns as exposures and the other eight studies (3 case‐control and 5 cohort studies) examined data‐driven dietary patterns. In two out of six studies describing unfavorable data‐driven dietary patterns, three dietary patterns (“animal products”, “starch rich” and “Western”) were found to have significantly positive associations with PanC risk with adjusted RR from 1.69 to 2.40. Contrastingly, three favorable data‐driven dietary patterns (“fruits and vegetables”, “vitamins and fiber” and “prudent”) were significantly inversely related to PanC risk with adjusted RR from 0.51 to 0.55 in three out of eight studies. All studies on a priori dietary patterns reported statistically significant results with adjusted RR ranging from 0.27 to 0.98, showing that greater adherence to Mediterranean diet, Healthy Eating Index‐2005 or diet with less inflammatory potential or more antioxidant capacity was associated with reduced PanC risk. Dietary patterns and PanC risk association was stronger in case‐control studies than cohort studies, and stronger among men than women.ConclusionInconsistent associations were observed between data‐driven dietary patterns and PanC risk. However, associations for a priori dietary patterns were consistent, suggesting that improved diet quality is associated with a reduced risk of PanC. More research is warranted to verify and explain the sex difference in strength of association between dietary patterns and PanC risk.Support or Funding InformationNo