ZHIZHONG ZHANG,1,* GELIN XU,1,* MINMIN MA,1 JIE YANG,2and XINFENG LIU1
Keywords: Diet; Stomach Cancer; Cancer Prevention; Epidemiology
BACKGROUND & AIMS:The association between dietaryfiber intake and gastric cancer risk has been investigated by many studies, with inconclusive results. Weconducted a meta-analysis of case-control and cohort studies to analyze this association.
METHODS:Relevantstudies were identified by searching PubMed and Embasethrough October 2012. We analyzed 21 articles, which included 580,064 subjects. Random-effects models were used to estimate summary relative risks. Dose-response,subgroup, sensitivity, meta-regression, and publicationbias analyses were performed.
RESULTS:The summary odds ratios of gastric cancer for the highest, compared with the lowest, dietaryfiber intake was 0.58 (95% confidence interval, 0.490.67) with significant heterogeneity among studies (P<.001, I 2 ¼62.2%).Stratified analysis for study design, geographic area, source and type offiber,Lauren’s classification, publication year, sample size, and quality score of study yielded consistent results. Doseresponse analysis associated a 10-g/day increment in fiber intake with a significant (44%) reduction in gastric cancer risk. Sensitivity analysis restricted to studies with control for conventional risk factors produced similar results, and omission of any single study had little effect on the combined risk estimate.
CONCLUSIONS: In a metaanalysis, we show that dietaryfiber intake is associated inversely with gastric cancer risk; the effect probably is independent of conventional risk factors. The direction of the protective association of dietary fiber was consistent among all studies, but the absolute magnitude was less certain because of heterogeneity among the studies. Further studies therefore are required to establish this association