The association between dietary vitamin A intake and pancreatic cancer risk: A meta-analysis of 11 studies

Whether dietary vitamin A intake could reduce pancreatic cancer risk is still conflicting. We therefore conducted a meta-analysis to summarize the evidence from epidemiological studies. We searched the databases of and Web of Knowledge up to July 2016. Random model was used to combine study-specific relative risks (RR) and 95% confidence interval (CI). Publication bias was assessed by Egger regression asymmetry test and Begg's funnel plot. Eleven studies (10 case-control studies and 1 cohort study) involving 2705 pancreatic cancer cases were included in the present study. The RR (95% CI) of pancreatic cancer for highest category of vitamin A intake compared with lowest category was 0.839 (95% CI = 0.712-0.988) with low heterogeneity detected (I² = 17.8%, P_{heterogeneity} = 0.274). The relationships were also significant for studies designed by case-control [RR = 0.808, 95% CI= 0.690-0.947], as well as in European population [RR = 0.821, 95% CI= 0.693-0.972]. No evidence of publication bias was found. This meta-analysis demonstrated that dietary vitamin A intake might inversely associated with the risk of pancreatic cancer.