Recent research does not show an association between fruit and vegetable consumption and bladder cancer risk. None of these studies looked at the variety in fruit and vegetable consumption, which may capture different aspects of fruit and vegetable consumption. We investigated whether the quantity and the variety in vegetable and fruit consumption are associated with bladder cancer risk in the European Prospective Investigation into Cancer and Nutrition study.
Data on usual food consumption and complete follow‐up for cancer occurrence was available for 478,533 participants, who were recruited in 10 European countries. A calibration study was conducted in an 8% representative subsample. After a mean follow‐up of 8.7 years, 1015 participants were diagnosed with bladder cancer. Diet Diversity Scores (DDSs) were used to quantify the variety in fruit and/or vegetable consumption by counting the number of different fruit and vegetable products eaten at least every two weeks. Multivariable Cox proportional hazard models were used to assess the effect of fruit and vegetable consumption and DDSs on the risk of bladder cancer.
Increments of 100 gram/day in fruit and vegetable consumption did not affect bladder cancer risk (calibrated hazard ratio (HR) 0.98; 95%CI: 0.95–1.01). A slightly stronger, although statistically non‐significant, inverse association was observed among never smokers (calibrated HR=0.92; 95%CI: 0.79–1.06 with increments of 100 g/day). Unexpectedly, more variety in fruit and vegetable products consumed increased bladder cancer risk (HR=1.30 95%CI=1.00–1.69 comparing the highest with the lowest tertile; p‐trend=0.05), which was strongest among never smokers (HR=1.72; 95%CI: 1.00–2.97). Continuous risk estimates did not reach statistical significance (HR for whole cohort 1.02 (95%CI 0.99–1.06 per 2 products increment); HR in never smokers 1.04 (95%CI 0.98–1.11 per 2 products increment)). The quantity and variety of fruit or vegetable consumption separately were not associated with bladder cancer risk.
We conclude that in EPIC quantity and variety of vegetable and fruit consumption is not associated with bladder cancer risk. Increased categorical risks for variety in vegetables and fruits without statistical significant findings in the continuous analyses may be due to chance. Our results provide further evidence that fruit and vegetable consumption does not strongly alter bladder cancer risk.
Citation Information: Cancer Prev Res 2010;3(1 Suppl):B103.