Dietary fat intake and risk of esophageal carcinoma: a meta-analysis of observational studies

Dietary fat intake is potentially associated with the onset of esophageal carcinoma (EC), but evidence from observational studies has remained unclear. This study aimed to evaluate the role of fat intake in the development of esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC). A systematic search was conducted in PubMed and Web of Science to identify all relevant studies. Studyspecific relative risks (RR) for the highest versus the lowest intake categories and 95% confidence intervals (CI) were pooled using a random-effects model. Seventeen case-control studies (2058 EAC cases, 1581 ESCC cases and 11696 controls) and two prospective cohort studies (494, 978 participants and 630 EAC cases and 215 ESCC cases) were identified. In EAC, the RRs (95% CI) were 1.69 (1.14-2.50) for total fat intake, 1.88 (1.28-2.77) for saturated fat (SFA) intake, 1.04 (0.86-1.27) for polyunsaturated fat (PUFA) intake and 1.70 (1.01-2.84) for monounsaturated fat (MUFA) intake. In ESCC, the RRs (95% CI) were 1.12 (0.84-1.51) for total fat, 1.38 (0.91-2.08) for SFA, 0.95 (0.55-1.62) for PUFA and 1.04 (0.65-1.66) for MUFA. In conclusion, total fat, SFA and MUFA intake were associated with EAC risk, but fat intake showed no significant association with ESCC risk. Large-scale prospective cohort studies are needed to confirm our findings.