Association between fruit and vegetable intake and risk for glioma: A meta-analysis

Objective: Epidemiologic studies evaluating the association between the intake of vegetables and fruit and the risk for glioma have produced inconsistent results. Therefore, the aim of this study was to test the hypothesis that higher vegetable and fruit intake may have a protective effect on risk for glioma. Methods: Pertinent studies were identified by a search in PubMed, Web of Knowledge, and Wan Fang Med Online up to January 2014. Random-effect model was used to combine study-specific results. Publication bias was estimated using Begg's funnel plot and Egger's regression asymmetry test. Results: Fifteen studies involving 5562 cases focusing on vegetable intake and 17 studies involving 3994 cases of fruit intake compared with the risk for glioma were included in this meta-analysis. The combined relative risk (RR) of glioma associated with vegetable intake was 0.775 (95% confidence interval [CI], 0.688-0.872) overall, and the association for subgroup analysis by study design, sources of control, ethnicity, and number of cases was consistent with overall data. For fruit intake and glioma risk, significant protective associations were found in an Asian population (RR, 0.573; 95% CI, 0346-0.947), but not in a white population. No publication bias was found. Conclusions: This analysis indicated that intake of vegetables might have a protective effect on glioma. The intake of fruit might have a protective effect on glioma in the Asian population; however, the results need to be confirmed. (C) 2014 Elsevier Inc. All rights reserved.