Ginseng Intake and Gastric Cancer Risk: A Meta-Analysis of Observational Epidemiological Studies

Abstract

Background: A number of observational studies have found that ginseng intake may reduce the risk of developing gastric cancer. However, studies have yielded inconsistent results as to whether consuming ginseng can lower the risk of gastric cancer. We conducted a meta-analysis of studies that assessed the association between ginseng intake and the risk of gastric cancer. Methods: We searched MEDLINE, EMBASE, CINAHL, KMbase, KoreaMed, RiCH, National Assembly Library, Riss4u, and DBPIA for studies released through August 2007. We manually searched the references. Two authors independently extracted the data. To assess the quality of the studies Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist for case-control studies and cohort studies were used. Review Manager 5.0 (RevMan) was used for statistical analysis. Results: We identified one case-control study and three cohort studies. The risk ratio (RR) for ginseng intake of all studies was 0.83 (95% confidence interval [CI], 0.46 to 1.51) and I 2 = 91% for heterogeneity. We did subgroup analysis according to different types of study design, nation, and author. The results were consistent only when we did subgroup analysis according to authors. The RR of subgroup by different authors was 1.43 (95% CI, 1.10 to 1.80) and I 2 = 0% without showing heterogeneity. Conclusion: In this meta-analysis, the results suggested that there was insufficient evidence to confirm the association between ginseng intake and the risk of gastric cancer. Subsequent more powerful, well-designed, and larger observational epidemiological studies are needed to clarify the association.