Intake of vegetables and fruit and risk of esophageal adenocarcinoma: a meta-analysis of observational studies

To study the association between the intake of fruit and vegetables and risk of esophageal adenocarcinoma (EAC), we summarized the evidence from observational studies in categorical and linear dose-response meta-analyses. Eligible studies published up to June 2013 were retrieved via computerized searches of MEDLINE and EMBASE. Random-effects models were used to calculate summary relative risks (SRRs) and the corresponding 95 % confidence intervals (CIs). Between-study heterogeneity was assessed using the Cochran's Q and I (2) statistics. A total of 12 studies involving 1,572 cases of EAC were included in this meta-analysis. Based on the highest versus lowest analysis, inverse associations were observed between intakes of vegetable (SRRs = 0.76, 95 % CIs 0.59-0.96; P (heterogeneity) = 0.098, I (2) 40.4 %; n = 9 studies), intakes of fruit (SRRs = 0.73, 95 % CIs, 0.55-0.98; P (heterogeneity) = 0.03, I (2) = 52.9 %; n = 9 studies), and intakes of total vegetables and fruit combined (SRRs = 0.68, 95 % CI 0.49-0.93; P (heterogeneity) = 0.162, I (2) = 38.9 %; n = 5 studies). Similar results were also observed in a linear dose-response analysis. These data support the hypothesis that intakes of vegetables and fruit may significantly reduce the risk of EAC. Further investigation with prospective designs, validated questionnaires, and good control of important confounders is warranted.