Consumption of Fruits, Vegetables and Bladder Cancer Risk: A Systematic Review and Meta-Analysis of Prospective Cohort Studies.

We examined the association between fruit/vegetable consumption and bladder cancer (BC) risk in a systematic review and meta-analysis of prospective cohort studies stratifying results by gender, smoking status and geographical region. Eligible studies were sought in MEDLINE and EMBASE up to April 20, 2020. Random-effects (DerSimonian-Laird) models were implemented for the calculation of pooled relative risks (RRs) and 95% confidence intervals (CI). Fifteen eligible studies were identified (1,993,881 subjects, 11,097 BC cases). Vegetable consumption (pooled RR = 0.95, 95% CI: 0.87-1.04, n = 10) as well as combined fruit/vegetable consumption was not associated with BC risk. Regarding fruit intake, the overall protective trend did not reach significance (pooled RR = 0.91, 95%CI: 0.81-1.02, n = 11); we found however a significant association in East Asians. A trend toward a protective association with citrus fruit consumption was also noted (pooled RR = 0.83, 95%CI: 0.69-1.01, n = 6), once again with a significant effect in East Asians. Moreover, no association was found regarding the subgroups of leafy vegetables, dark green vegetables, and berries. Single studies pointed to a reduced BC risk in never smoking males consuming cruciferous vegetables and East Asians consuming yellow vegetables. In conclusion, our study reveals possible protective effects; larger studies are needed to investigate the emerging trends.

Association of obesity and other anthropometric characteristics with bladder cancer risk: a systematic review and meta-analysis of longitudinal cohort studies.

PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the potential associations between anthropometric characteristics and bladder cancer risk, synthesizing longitudinal cohort studies. METHODS: Literature search across MEDLINE, EMBASE, Scopus, Google Scholar and Cochrane Central was performed up to December 31, 2019 and data abstraction was performed independently by two authors. Random-effects (DerSimonian-Laird) models were used to estimate pooled relative risks (RR) and 95% confidence intervals (95%CI); subgroup analyses were performed in geographical region, mean age, publication year, length of follow-up, sample size, method of body mass index (BMI) estimation and adjustment for smoking. RESULTS: 27 studies were included (88 593 bladder cancer cases in a total cohort of 49 647 098 subjects). Increased bladder cancer risk was noted in overweight men (pooled RR=1.12, 95%CI: 1.04-1.21) but not in overweight women. Both obese men (pooled RR=1.14, 95%CI: 1.06-1.22) and women (pooled RR=1.19, 95%CI: 1.02-1.38) showed increased risk. Interestingly, height increase per 5 cm did not seem to affect risk of bladder cancer in men (pooled RR=1.03, 95%CI: 0.99- 1.06) and women (pooled RR=1.02, 95%CI: 0.97-1.06). Larger waist circumference was associated with bladder cancer risk in men (pooled RR=1.18, 95%CI: 1.09-1.26) but not women. CONCLUSION: Bladder cancer risk seems to be related with obesity overall and central obesity in men. In contrast to other cancer types, height does not seem to affect risk, but more studies are needed to extract safe conclusions.