The Association between Dietary Protein Intake and the Risk of Pancreatic Cancer: Evidence from 14 Publications.

Many studies have been published to assess the association about dietary protein intake on the risk of pancreatic cancer, but with inconsistent result. This meta-analysis aimed to evaluate whether protein intake could affect the risk of pancreatic cancer. A systematic literature search was performed in PubMed, EMBASE and Web of Science up to October 1, 2019. Pooled relative risks (RR) and 95% confidence intervals (CI) were calculated using a random-effect model. A total of 14 studies (12 case-control studies and two cohort studies) were included. Overall, total protein intake had no significant association on the risk of pancreatic cancer (RR = 1.02, 95%CI= 0.85-1.22, I2=45.7%). Subgroup analyses showed such relationships were almost not influenced by study design and geographic location. Interestingly, when we performed the subgroup analysis by protein type, the opposite association was found in animal protein intake (RR = 1.37, 95%CI= 0.93-2.01) and vegetable protein intake (RR = 0.78, 95%CI= 0.54-1.14), although these two groups were not statistically significant. In conclusion, this meta-analysis indicated that dietary total protein intake may be not associated with the risk of pancreatic cancer. However, protein type may be affecting the result which was found from our research. Therefore, studies with detailed information, especially protein type, are warranted to further confirm these findings.