The effect of fruit and vegetable intake on the development of lung cancer: a meta-analysis of 32 publications and 20 414 cases

BACKGROUND/OBJECTIVES: Quantification of the association between the intake of vegetables and fruits and the risk of lung cancer is controversial. Thus, we conducted a meta-analysis to assess the relationship between vegetables and fruits and lung cancer risk. SUBJECTS/METHODS: Pertinent studies were identified by a search in PubMed and Web of Knowledge. Random-effects models were used to calculate summary relative risks (RR) and the corresponding 95% confidence intervals (CI). Publication bias was estimated using Begg's test. RESULTS: Finally, 30 articles with 37 studies comprising of 20 075 lung cancer cases for vegetables intake with lung cancer risk and 31 articles with 38 studies comprising of 20 213 lung cancer cases for fruits intake with lung cancer risk were included in this meta-analysis. The combined results showed that there were significant associations between vegetables and fruits intake and lung cancer risk. The pooled RR were 0.74 (95% CI: 0.67, 0.82) for vegetables and 0.80 (95% CI: 0.74, 0.88) for fruits. Significant association was found in females on vegetables intake and lung cancer but not in males. The association was also stronger in females than males on fruits intake and lung cancer risk. No publication bias was detected. CONCLUSIONS: Our analysis indicated that intake of vegetables and fruits may have a protective effect on lung cancer, and the associations were stronger in females. As the potential biases and confounders could not be ruled out completely in this meta-analysis, further studies are needed.