Fruit consumption and the risk of bladder cancer: a pooled analysis by the BLadder cancer Epidemiology and Nutritional Determinants study

While the association between fruit consumption and bladder cancer risk has been extensively reported, studies have had inadequate statistical power to investigate associations between types of fruit and bladder cancer risk satisfactorily. Fruit consumption in relation to bladder cancer risk was investigated by pooling individual data from 13 cohort studies. Cox regression models with attained age as time scale were used to estimate hazard ratios (HRs) for intakes of total fruit and each of citrus fruits, soft fruits, stone fruits, tropical fruits, pome fruits, and fruit products. Analyses were stratified by sex, smoking status, and bladder cancer subtype. During on average 11.2 years of follow-up, 2836 individuals developed incident bladder cancer. Increasing fruit consumption (by 100 gram/day) was inversely associated with the risk of bladder cancer in women (HR=0.92; 95% CI 0.85-0.99). Although in women the association with fruit consumption was most evident for higher-risk non-muscle invasive bladder cancer (NMIBC) (HR=0.72; 95% CI 0.56 0.92), the test for heterogeneity by bladder cancer subtype was non-significant (p heterogeneity=0.14). Increasing fruit consumption (by 100 gram/day) was not associated with bladder cancer risk in men (HR=0.99; 95% CI 0.94-1.03), never smokers (HR=0.96; 95% CI 0.88-1.05), former smokers (HR=0.98; 95% CI 0.92 1.05), or current smokers (HR=0.95; 95% CI 0.89-1.01). The consumption of any type of fruit was not found to be associated with bladder cancer risk (p-values>0.05). This study supports no evidence that the consumption of specific types of fruit reduces the risk of bladder cancer. However, increasing fruit consumption may reduce bladder cancer risk in women