Objective: This meta-analysis of cohort and case-control studies was undertaken to evaluate the relationship between cruciferous vegetables intake and risk of bladder cancer.
Methods: Eligible studies were retrieved via both computer searches and review of references. The summary relative risks (RRs) with 95% confidence interval (CI) for the highest versus the lowest intake of cruciferous vegetables were calculated. Heterogeneity and publication bias were also evaluated.
Results: Five cohort and five case-control studies were included. A significantly decreased risk with bladder cancer was observed in overall cruciferous vegetables intake group (RR = 0.80; 95% CI 0.69-0.92) and subgroup of case-control studies (RR = 0.78; 95% CI, 0.67-0.89), but not in cohort studies (RR = 0.86; 95% CI, 0.61-1.11). No heterogeneity and publication bias were detected across studies.
Conclusion: Our findings support that cruciferous vegetables intake was related to the decreased risk of bladder cancer. Because of the limited number of studies, further well-designed prospective studies are needed to explore the protective effect of cruciferous vegetables on bladder cancer.