Association of dietary intake and serum levels of unsaturated fatty acids and risk of pancreatic cancer: A GRADE-assessed systematic review and dose-response meta-analysis of prospective cohort studies.

Lifestyle and dietary factors contribute to about one-third of cancer deaths. The fatty acid composition in diets may be related to pancreatic cancer. A prior meta-analysis examining the connection between mono- and polyunsaturated fatty acid intake and pancreatic cancer risk has not investigated the dose-response relationship. This systematic review and dose-response meta-analysis aims to explore the association between dietary intake and serum levels of unsaturated fatty acids and the risk of pancreatic cancer in adults. A systematic search was conducted across electronic databases, including PubMed, ISI Web of Science, Scopus, and Google Scholar, through April 2026. Thirteen studies involving 1,268,249 participants were eligible for inclusion in the systematic review meta-analysis. During follow-up periods ranging from 8 to 22 years, 4766 cases of pancreatic cancer were recorded. The highest-versus-lowest comparison showed summary risk estimates for PUFA (RR: 0.87, 95% CI: 0.73, 1.03), MUFA (RR: 1.01, 95% CI: 0.81, 1.26), and omega-3 (RR: 1.11, 95% CI: 0.88, 1.40). We found no significant association for dietary intake of unsaturated fatty acids. However, subgroup analyses showed a significant association for PUFA (RR: 0.81, 95% CI: 0.66, 0.99), DHA (RR: 0.75, 95% CI: 0.62, 0.91), and EPA (RR: 0.79, 95% CI: 0.65, 0.96) in studies with ≥ 10 years follow-up duration. Furthermore, non-linear dose-response analysis indicated that consuming 18-30 g/day of oleic acid was inversely associated with pancreatic cancer risk. Regarding circulating fatty acid levels, a significant inverse association was observed for PUFA (RR: 0.82, 95% CI: 0.68,0.98), while no significant associations were found for other fatty acids. Dietary intake of unsaturated fatty acids was not significantly associated with pancreatic cancer risk overall; however, specific intakes, particularly oleic acid, may be protective.