Abstract:
Objective To explore the association between esophageal cancer and serum vitamin E level and to provide evidences for researches and prevention of esophageal cancer.
Methods Case-control studies on esophageal cancer and serum vitamin E level published from January 1980 to December 2015 were searched through China National Knowledge Infrastructure,Wanfang Database,PubMed,and Web of Science.Meta-analysis was performed with Stata 12.0.
Results A total of 9 literatures (7 in Chinese and 2 in English),involving in 358 esophageal cancer cases and 538 controls,were included in the meta-analysis.The meta-analysis showed that the serum vitamin E level of esophageal cancer cases was lower than that of the controls (standardized mean differenceSMD=-0.50,95% confidence interval95%
CI=-0.65-0.36,
P<0.001).Subgroup analysis found that the serum vitamin E levels of the esophageal cancer cases were lower than those of the controls for the studies conducted in China (SMD=-0.50,95%
CI=-0.67-0.33) and in United States (SMD=-0.51,95%
CI=-0.77-0.25),with the controls selected from communities (SMD=-0.54,95%
CI=-0.69-0.39),with the sample size of larger than 50 (SMD=-0.56,95%
CI=-0.71-0.41),with age-matched controls (SMD=-0.57,95%
CI=-0.72-0.42),and with serum vitamin E level detection using high performance liquid chromatography (HPLC)(SMD=-0.41,95%
CI=-0.59-0.24)and using method other than HPLC (SMD=-0.67,95%
CI=-0.91-0.43)(all
P<0.001).Sensitivity analysis and publication bias test showed that the results of the study were stable and there was no publication bias for the literatures included in the study.
Conclusion Serum vitamin E level is low in esophageal cancer patients.