UCLA

Purpose

High consumption of fruits and vegetables decrease the risk of bladder cancer (BC). The evidence of specific fruits and vegetables and the BC risk is still limited.

Methods

Fruit and vegetable consumptions in relation to BC risk was examined by pooling individual participant data from case-control studies. Unconditional logistic regression was used to estimate study-specific odds ratio's (ORs) with 95% confidence intervals (CIs) and combined using a random-effects model for intakes of total fruits, total vegetables, and subgroups of fruits and vegetables.

Results

A total of 11 case-control studies were included, comprising 5637 BC cases and 10,504 controls. Overall, participants with the highest intakes versus the lowest intakes of fruits in total (OR 0.79; 95% CI 0.68-0.91), citrus fruits (OR 0.81; 95% CI 0.65-0.98), pome fruits (OR 0.76; 95% CI 0.65-0.87), and tropical fruits (OR 0.84; 95% CI 0.73-0.94) reduced the BC risk. Greater consumption of vegetables in total, and specifically shoot vegetables, was associated with decreased BC risk (OR 0.82; 95% CI 0.68-0.96 and OR 0.87; 95% CI 0.78-0.96, respectively). Substantial heterogeneity was observed for the associations between citrus fruits and total vegetables and BC risk.

Conclusion

This comprehensive study provides compelling evidence that the consumption of fruits overall, citrus fruits, pome fruits and tropical fruits reduce the BC risk. Besides, evidence was found for an inverse association between total vegetables and shoot vegetables intake.