Intake of fruit and vegetables and risk of bladder cancer: a dose–response meta-analysis of observational studies

Baodong Yao, Yujie Yan, Xianwu Ye, Hong Fang, Huilin Xu, Yinan Liu, Sheran Li, Yanping Zhao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


Background: Observational studies suggest an association between fruit and vegetables intake and risk of bladder cancer, but the results are controversial.

Methods: We therefore summarized the evidence from observational studies in categorical, linear, and nonlinear, dose–response meta-analysis. Pertinent studies were identified by searching EMBASE and PubMed from their inception to August 2013.

Results: Thirty-one observational studies involving 12,610 cases and 1,121,649 participants were included. The combined rate ratio (RR, 95 % CI) of bladder cancer for the highest versus lowest intake was 0.83 (0.69–0.99) for total fruit and vegetables, 0.81 (0.70–0.93) for total vegetables, 0.77 (0.69–0.87) for total fruit, 0.84 (0.77–0.91) for cruciferous vegetables, 0.79 (0.68–0.91) for citrus fruits, and 0.74 (0.66–0.84) for yellow–orange vegetables. Subgroup analysis showed study design and gender as possible sources of heterogeneity. A nonlinear relationship was found of citrus fruits intake with risk of bladder cancer (Pfor nonlinearity = 0.018), and the RRs (95 % CI) of bladder cancer were 0.87 (0.78–0.96), 0.80 (0.67–0.94), 0.79 (0.66–0.94), 0.79 (0.65–0.96), and 0.79 (0.64–0.99) for 30, 60, 90, 120, and 150 g/day. A nonlinear relationship was also found of yellow–orange vegetable intake with risk of bladder cancer risk (Pfor nonlinearity = 0.033). Some evidence of publication bias was observed for fruit, citrus fruits, and yellow–orange vegetables.

Conclusion: This meta-analysis supports the hypothesis that intakes of fruit and vegetables may reduce the risk of bladder cancer. Future well-designed studies are required to confirm this finding.

Original languageEnglish
Pages (from-to)1645-1658
Number of pages14
JournalCancer Causes and Control
Issue number12
Publication statusPublished - 18 Nov 2014
Externally publishedYes


  • bladder cancer
  • bladder neoplasms
  • meta-analysis
  • fruit
  • vegetable


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