Vitamin E intake and pancreatic cancer risk: a meta-analysis of observational studies.
BACKGROUND
Some epidemiological studies have suggested that vitamin E intake reduces the risk of pancreatic cancer; however, this conclusion has not been supported by all the published studies. We conducted a meta-analysis to assess the relationship between vitamin E intake and the risk of pancreatic cancer by combining the results from published articles.


METHODS
We searched the published studies that reported the relationship between vitamin E intake and pancreatic cancer risk using the PubMed, Web of Science, and Embase databases through December 31st, 2014. Based on a fixed-effects or random-effects model, the RR and 95% CI were used to assess the combined risk.


RESULTS
In total, 10 observational studies (6 case-control studies and 4 cohort studies) were included. The overall RR (95% CI) of pancreatic cancer for the highest vs. the lowest level of vitamin E intake was 0.81 (0.73, 0.89). We found little evidence of heterogeneity (I2=19.8%, P=0.255). In the subgroup analyses, we found an inverse association between vitamin E intake and pancreatic cancer risk both in the case-control and cohort studies. Additionally, this inverse association was not modified by different populations.


CONCLUSIONS
In our meta-analysis, there was an inverse association between vitamin E intake and the risk of pancreatic cancer. A high level of vitamin E might be a protective factor for populations at risk for pancreatic cancer.
Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China (mainland).
Lujian
L
Peng
Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China (mainland).
Xiangde
X
Liu
Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China (mainland).
Qian
Q
Lu
Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China (mainland).
Tengqian
T
Tang
Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China (mainland).
Zhanyu
Z
Yang
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016588:Anticarcinogenic Agents / Q000008:administration & dosage; D000975:Antioxidants / Q000008:administration & dosage / Q000502:physiology*; D001208:Asia / Q000453:epidemiology; D016022:Case-Control Studies; D015331:Cohort Studies; D019587:Dietary Supplements; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064887:Observational Studies as Topic / Q000706:statistics & numerical data*; D010190:Pancreatic Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D012107:Research Design; D012306:Risk; D012307:Risk Factors; D018401:Sample Size; D014481:United States / Q000453:epidemiology; D014810:Vitamin E / Q000008:administration & dosage / Q000502:physiology*; D055815:Young Adult
D016588:Anticarcinogenic Agents; D000975:Antioxidants; D014810:Vitamin E