Consumption of vegetables and fruit and the risk of bladder cancer in the European Prospective Investigation into Cancer and Nutrition

Unveiling the Effects of Cruciferous Vegetable Intake on Different Cancers: A Systematic Review and Dose-Response Meta-analysis

CONTEXT

Epidemiological studies indicated that cruciferous vegetable intake is associated with positive health outcomes. However, the role of cruciferous vegetables may have differential impacts on various cancers.

OBJECTIVE

This meta-analysis aims to review recent epidemiological studies on the link between cruciferous vegetables and various cancers. It seeks to identify the optimal intake dose and timing of cruciferous vegetables influencing their association with cancer risk.

DATA SOURCES

Studies on cruciferous vegetables and cancer were searched in PubMed, NCBI, Web of Science, and Elsevier databases from 1978 to June 2023.

DATA EXTRACTION

Extracted data from 226 relevant case-control and cohort studies were expressed by standardized mean difference and 95% CI, followed by the subgroup analysis to eliminate heterogeneity.

RESULTS

Intake of cruciferous vegetables can prevent cancers, with an odds ratio of 0.77 and risk ratio (RR) of 0.96. The intake levels of cruciferous vegetables associated with the risk of colorectal cancer, lung cancer, upper gastrointestinal cancer, gynecological cancer (ovarian cancer and endometrial cancer), bladder cancer, renal cancer, and prostate cancer were found to be 5.41 servings/week, 5.41 servings/week, 5.5 servings/week, 7.4 servings/week, 5.5 servings/week, 4.85 servings/week, and 3 servings/week, respectively. In a cohort followed for 2 to 15 years, limited consumption of cruciferous vegetables was correlated with a higher cancer RR. In the Asian population, cruciferous vegetables had a significant relationship with lung cancer, head and neck squamous cell carcinoma, and esophageal cancer. Conversely, cruciferous vegetables are predominantly associated with colorectal, renal, gynecological, and prostate cancer in the American population.

CONCLUSION

This study highlights the complex link between cruciferous vegetables and cancer, influenced by factors such as cancer type, region, intake level, and follow-up duration.

Fruits and vegetables intake and bladder cancer risk: a pooled analysis from 11 case-control studies in the BLadder cancer Epidemiology and Nutritional Determinants (BLEND) consortium

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.

Vegetable and fruit intake and the risk of bladder cancer: Japan Public Health Center-based prospective study

BACKGROUND

Vegetable and fruit consumption may have a protective effect against several types of cancer. However, evidence suggesting that increased intake of vegetables and fruits, their subtypes, or the antioxidant nutrients they contain in abundance decreases the risk of bladder cancer is limited.

METHODS

This study included 80,952 participants from the Japan Public Health Center-based Prospective Study, who responded to a food frequency questionnaire in a 5-year follow-up survey in 1995-1998 and were followed up until December 2015 to investigate the associations between intake of vegetables and fruits, their subtypes, or the antioxidant nutrients and bladder cancer risk using Cox proportional hazards regression models.

RESULTS

Within 1,287,514 person-years of follow-up, 401 bladder cancer cases (307 men and 94 women) were diagnosed. No association was found between intake of total vegetable and fruit, total vegetable, total fruit, subtypes of vegetables and fruits, or antioxidant nutrients and bladder cancer risk in both men and women, even in the analyses conducted among men stratified by smoking status.

CONCLUSIONS

In this population, the consumption of vegetables and fruits was not associated with the risk of bladder cancer.

Clinical Potential of Fruit in Bladder Cancer Prevention and Treatment

Bladder cancer (BC) is the most common tumor of the urinary system in the world. Moreover, despite using anticancer therapies, BC is also characterized by a high recurrence risk. Among numerous risk factors, cigarette smoking, occupational exposure to certain aromatic compounds, and genetic factors contribute most strongly to BC development. However, the epidemiological data to date suggests that diet quality may influence some carcinogenic factors of BC and, therefore, might have a preventative effect. Adequate consumption of selected fruits with scientifically proven properties, including pomegranates and cranberries, can significantly reduce the risk of developing BC, even in those at risk. Therefore, in this article, we aim to elucidate, using available literature, the role of fruits, including pomegranates, cranberries, citrus fruits, cactus pears, and apples, in BC prevention and treatment. Previous data indicate the role of compounds in the above-mentioned fruits in the modulation of the signaling pathways, including cell proliferation, cell growth, cell survival, and cell death.

Onco-Preventive and Chemo-Protective Effects of Apple Bioactive Compounds

Cancer is one of the leading causes of death globally. Epidemiological studies have strongly linked a diet high in fruits to a lower incidence of cancer. Furthermore, extensive research shows that secondary plant metabolites known as phytochemicals, which are commonly found in fruits, have onco-preventive and chemo-protective effects. Apple is a commonly consumed fruit worldwide that is available all year round and is a rich source of phytochemicals. In this review, we summarize the association of apple consumption with cancer incidence based on findings from epidemiological and cohort studies. We further provide a comprehensive review of the main phytochemical patterns observed in apples and their bioavailability after consumption. Finally, we report on the latest findings from in vitro and in vivo studies highlighting some of the key molecular mechanisms targeted by apple phytochemicals in relation to inhibiting multiple 'hallmarks of cancer' that are important in the progression of cancer.

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.

Vegetable intake and the risk of bladder cancer in the BLadder Cancer Epidemiology and Nutritional Determinants (BLEND) international study

BACKGROUND

Although a potential inverse association between vegetable intake and bladder cancer risk has been reported, epidemiological evidence is inconsistent. This research aimed to elucidate the association between vegetable intake and bladder cancer risk by conducting a pooled analysis of data from prospective cohort studies.

METHODS

Vegetable intake in relation to bladder cancer risk was examined by pooling individual-level data from 13 cohort studies, comprising 3203 cases among a total of 555,685 participants. Pooled multivariate hazard ratios (HRs), with corresponding 95% confidence intervals (CIs), were estimated using Cox proportional hazards regression models stratified by cohort for intakes of total vegetable, vegetable subtypes (i.e. non-starchy, starchy, green leafy and cruciferous vegetables) and individual vegetable types. In addition, a diet diversity score was used to assess the association of the varied types of vegetable intake on bladder cancer risk.

RESULTS

The association between vegetable intake and bladder cancer risk differed by sex (P-interaction = 0.011) and smoking status (P-interaction = 0.038); therefore, analyses were stratified by sex and smoking status. With adjustment of age, sex, smoking, energy intake, ethnicity and other potential dietary factors, we found that higher intake of total and non-starchy vegetables were inversely associated with the risk of bladder cancer among women (comparing the highest with lowest intake tertile: HR = 0.79, 95% CI = 0.64-0.98, P = 0.037 for trend, HR per 1 SD increment = 0.89, 95% CI = 0.81-0.99; HR = 0.78, 95% CI = 0.63-0.97, P = 0.034 for trend, HR per 1 SD increment = 0.88, 95% CI = 0.79-0.98, respectively). However, no evidence of association was observed among men, and the intake of vegetable was not found to be associated with bladder cancer when stratified by smoking status. Moreover, we found no evidence of association for diet diversity with bladder cancer risk.

CONCLUSION

Higher intakes of total and non-starchy vegetable are associated with reduced risk of bladder cancer for women. Further studies are needed to clarify whether these results reflect causal processes and potential underlying mechanisms.

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 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 g/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 nonmuscle invasive bladder cancer (NMIBC; HR = 0.72; 95% CI 0.56-0.92), the test for heterogeneity by bladder cancer subtype was nonsignificant (P-heterogeneity = .14). Increasing fruit consumption (by 100 g/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 > .05). Our study supports no evidence that the consumption of specific types of fruit reduces the risk of bladder cancer. However, increasing total fruit consumption may reduce bladder cancer risk in women.

Menstrual Factors, Reproductive History, Hormone Use, and Urothelial Carcinoma Risk: A Prospective Study in the EPIC Cohort

BACKGROUND

Urothelial carcinoma is the predominant (95%) bladder cancer subtype in industrialized nations. Animal and epidemiologic human studies suggest that hormonal factors may influence urothelial carcinoma risk.

METHODS

We used an analytic cohort of 333,919 women from the European Prospective Investigation into Cancer and Nutrition Cohort. Associations between hormonal factors and incident urothelial carcinoma (overall and by tumor grade, tumor aggressiveness, and non-muscle-invasive urothelial carcinoma) risk were evaluated using Cox proportional hazards models.

RESULTS

During a mean of 15 years of follow-up, 529 women developed urothelial carcinoma. In a model including number of full-term pregnancies (FTP), menopausal status, and menopausal hormone therapy (MHT), number of FTP was inversely associated with urothelial carcinoma risk (HR≥5vs1 = 0.48; 0.25-0.90; P trend in parous women = 0.010) and MHT use (compared with nonuse) was positively associated with urothelial carcinoma risk (HR = 1.27; 1.03-1.57), but no dose response by years of MHT use was observed. No modification of HRs by smoking status was observed. Finally, sensitivity analyses in never smokers showed similar HR patterns for the number of FTP, while no association between MHT use and urothelial carcinoma risk was observed. Association between MHT use and urothelial carcinoma risk remained significant only in current smokers. No heterogeneity of the risk estimations in the final model was observed by tumor aggressiveness or by tumor grade. A positive association between MTH use and non-muscle-invasive urothelial carcinoma risk was observed.

CONCLUSIONS

Our results support that increasing the number of FTP may reduce urothelial carcinoma risk.

IMPACT

More detailed studies on parity are needed to understand the possible effects of perinatal hormone changes in urothelial cells.

Dietary factors associated with bladder cancer

It is biologically plausible for dietary factors to influence bladder cancer risk considering that beneficial as well as harmful components of a diet are excreted through the urinary tract and in direct contact with the epithelium of the bladder. However, studies that investigated the association between dietary factors and bladder cancer (BC) risk have largely reported inconsistent results. The macronutrient intake and risk of BC could have yield inconsistent results across studies because of lack of details on the type, source and the quantities of different dietary fatty acids consumed. There is evidence to suggest that consumption of processed meat may increase BC risk. Dietary carbohydrate intake does not appear to be directly associated with BC risk. Even though a large number of studies have investigated the association between fruit/vegetable consumption/micronutrients in those and BC risk, they have yielded inconsistent results. Gender-specific subgroup analysis, details of how fruits and vegetables are consumed (raw vs. cooked), adequate control for smoking status/aggressiveness of the cancer and consideration of genetic make-up may clarify these inconsistent results. There is no strong evidence to suggest that supplementation with any common micronutrient is effective in reducing BC risk. These limitations in published research however do not totally eclipse the observation that a diet rich in fruits and vegetables and low in processed meat along with especially smoking cessation may convey some protective effects against BC risk.

Association between selected dietary scores and the risk of urothelial cell carcinoma: A prospective cohort study

Studies investigating the association of food and nutrient consumption with the risk of urothelial cell carcinoma (UCC) have produced mixed results. We used three common dietary scores, the Mediterranean Diet Score (MDS), the Alternate Healthy Eating Index 2010 (AHEI-2010) and the Dietary Inflammatory Index (DII) to assess the evidence of an association between diet and the risk of UCC. Over a median follow-up time of 21.3 years, 379 incident UCC cases were diagnosed. Dietary scores were calculated using data from a 121-item food frequency questionnaire administered at baseline. We used Cox models to compute hazard ratios (HR) for the association between dietary scores (per one standard deviation) and UCC risk. In order to reflect overall adherence to a healthy diet, a metascore was constructed by summing the quintiles of each of the three scores. None of the dietary scores was associated with the risk of UCC overall. A healthier diet was found to be inversely associated with the risk of invasive (MDS: HR = 0.86, 95% CI: 0.74-1.00, metascore: HR = 0.84, 95% CI: 0.71-0.98), but not superficial disease (heterogeneity between subtypes p = 0.04 and p = 0.03, respectively). Results were consistent but weaker for the DII and the AHEI-2010. We found some evidence of effect modification by smoking, in particular for the metascore (Current: HR = 0.77, 95% CI: 0.58-1.01, Former: HR = 0.77, 95% CI: 0.64-0.92, Never: HR = 1.01, 95% CI: 0.81-1.26, p for heterogeneity = 0.05). A healthy diet may be protective against the risk of invasive, but not superficial, UCC. Promoting healthy dietary habits may help lower the risk of invasive UCC, especially for current and former smokers.

Apple intake and cancer risk: a systematic review and meta-analysis of observational studies

OBJECTIVE

Conflicting results on the association between fruit consumption and cancer risk have been reported. Little is known about the cancer preventive effects of different fruit types. The present meta-analysis investigates whether an association exists between apple intake and cancer risk.

DESIGN

Relevant observational studies were identified by literature search (PubMed, Web of Science and Embase). A random-effect model was used to estimate the cancer risk in different anatomical sites. Between-study heterogeneity and publication bias were assessed using adequate statistical tests.

RESULTS

Twenty case-control (three on lung, five on colorectal, five on breast, two on oesophageal, three on oral cavity, two on prostate and one each on pancreas, bladder, larynx, ovary, kidney and brain cancer) and twenty-one cohort (seven on lung, two on colorectal, three on breast and one each on oesophageal, pancreas, bladder, kidney, endometrial, head-neck, urothelial and stomach cancer) studies met the inclusion criteria. Comparing the highest v. lowest level of apple consumption, the reduction of lung cancer risk was statistically highly significant in both case-control (OR=0·75; 95% CI 0·63, 0·88; P=0·001, I 2=0 %) and cohort studies (relative risk=0·89; 95% CI 0·84, 0·94; P<0·001, I 2=53 %). Instead, in the case of colorectal (OR=0·66; 95% CI 0·54, 0·81; P<0·001, I 2=55%), breast (OR=0·79; 95% CI 0·73, 0·87; P<0·001, I 2=1 %) and overall digestive tract (OR=0·50; 95% CI 0·36, 0·69; P<0·001, I 2=90 %) cancers a significant preventive effect of apples was found only in case-control studies while prospective studies indicated no effect. No evidence of publication bias could be detected for colorectal, oral cavity, oesophageal and breast cancer. However, some confounding effects may be present and related to the consumption of other fruit which have not been considered as adjusting factors.

CONCLUSIONS

The present meta-analysis indicates that consumption of apples is associated with a reduced risk of cancer in different anatomical sites.

Fruits and vegetables intake and risk of bladder cancer: a PRISMA-compliant systematic review and dose-response meta-analysis of prospective cohort studies

Clinical practice recommends eating ≥2.5 cups of fruits and vegetables (FVs) each day for cancer prevention, in which the evidence from epidemiological studies for the association between FVs intake and bladder cancer (BC) prevention is inconsistent.We searched the PubMed, Embase, and Willy online Library for relevant studies published up to September 27, 2014. Prospective cohort studies investigated FVs intake, and the risk of BC with ≥3 categories of exposure was included. A dose-response meta-analysis was carried out to evaluate the association between FVs intake and risk of BC.Fourteen cohorts with 17 studies including 9447 cases were identified. No evidence of nonlinear association was examined between FVs intake and risk of BC. The summarized relevant risk (RR) of every 0.2 serving increment a day was 1.00 (95%CI: 0.99, 1.00; P = 0.17; I = 41.7%; n = 14) for total fruits; 0.99 (95%CI: 0.96, 1.01; P = 0.28; I = 37.0%; n = 13) for total vegetables; and 0.99 (95%CI: 0.97, 1.01; P = 0.24; I = 57.5%; n = 8) for both FVs. In further analysis, we observed inverse association between every 0.2 serving increment of green leafy vegetables intake a day and risk of BC (RR = 0.98, 95%CI: 0.96, 0.99; I = 0.0%; P < 0.01; Power = 0.76; n = 6), but neither for cruciferous vegetables (RR = 0.97, 95%CI: 0.93, 1.01; P = 0.19; I = 55.8%; n = 8) nor for citrus (RR = 1.00, 95%CI: 1.00, 1.00; P = 0.83; I = 0.0%; n = 7). Subgroup analysis showed consistent results.Little evidence supports a beneficial effect for total fruits, vegetables, both FVs, and citrus intake against bladder cancer. Green leafy vegetables may help prevent bladder cancer.

Fruits, vegetables, and bladder cancer risk: a systematic review and meta-analysis

Smoking is estimated to cause about half of all bladder cancer cases. Case-control studies have provided evidence of an inverse association between fruit and vegetable intake and bladder cancer risk. As part of the World Cancer Research/American Institute for Cancer Research Continuous Update Project, we conducted a systematic review and meta-analysis of prospective studies to assess the dose-response relationship between fruit and vegetables and incidence and mortality of bladder cancer. We searched PubMed up to December 2013 for relevant prospective studies. We conducted highest compared with lowest meta-analyses and dose-response meta-analyses using random effects models to estimate summary relative risks (RRs) and 95% confidence intervals (CIs), and used restricted cubic splines to examine possible nonlinear associations. Fifteen prospective studies were included in the review. The summary RR for an increase of 1 serving/day (80 g) were 0.97 (95% CI: 0.95-0.99) I(2)  = 0%, eight studies for fruits and vegetables, 0.97 (95% CI: 0.94-1.00, I(2)  = 10%, 10 studies) for vegetables and 0.98 (95% CI: 0.96-1.00, I(2)  = 0%, 12 studies) for fruits. Results were similar in men and women and in current, former and nonsmokers. Amongst fruits and vegetables subgroups, for citrus fruits the summary RR for the highest compared with the lowest intake was 0.87 (95% CI: 0.76-0.99, I(2)  = 0%, eight studies) and for cruciferous vegetables there was evidence of a nonlinear relationship (P = 0.001). The current evidence from cohort studies is not consistent with a role for fruits and vegetables in preventing bladder cancer.

Flavonoid and lignan intake in relation to bladder cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

BACKGROUND

There is growing evidence of the protective role of dietary intake of flavonoids and lignans on cancer, but the association with bladder cancer has not been thoroughly investigated in epidemiological studies. We evaluated the association between dietary intakes of total and subclasses of flavonoids and lignans and risk of bladder cancer and its main morphological type, urothelial cell carcinoma (UCC), within the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

METHODS

A cohort of 477 312 men and women mostly aged 35-70 years, were recruited in 10 European countries. At baseline, dietary flavonoid and lignan intakes were estimated using centre-specific validated questionnaires and a food composition database based on the Phenol-Explorer, the UK Food Standards Agency and the US Department of Agriculture databases.

RESULTS

During an average of 11 years of follow-up, 1575 new cases of primary bladder cancer were identified, of which 1425 were UCC (classified into aggressive (n=430) and non-aggressive (n=413) UCC). No association was found between total flavonoid intake and bladder cancer risk. Among flavonoid subclasses, significant inverse associations with bladder cancer risk were found for intakes of flavonol (hazard ratio comparing fifth with first quintile (HRQ5-Q1) 0.74, 95% confidence interval (CI): 0.61-0.91; P-trend=0.009) and lignans (HRQ5-Q1 0.78, 95% CI: 0.62-0.96; P-trend=0.046). Similar results were observed for overall UCC and aggressive UCC, but not for non-aggressive UCC.

CONCLUSIONS

Our study suggests an inverse association between the dietary intakes of flavonols and lignans and risk of bladder cancer, particularly aggressive UCC.

Intake of fruit and vegetables and risk of bladder cancer: a dose-response meta-analysis of observational studies

BACKGROUND

Observational studies suggest an association between fruit and vegetables intake and risk of bladder cancer, but the results are controversial.

METHODS

We therefore summarized the evidence from observational studies in categorical, linear, and nonlinear, dose-response meta-analysis. Pertinent studies were identified by searching EMBASE and PubMed from their inception to August 2013.

RESULTS

Thirty-one observational studies involving 12,610 cases and 1,121,649 participants were included. The combined rate ratio (RR, 95 % CI) of bladder cancer for the highest versus lowest intake was 0.83 (0.69-0.99) for total fruit and vegetables, 0.81 (0.70-0.93) for total vegetables, 0.77 (0.69-0.87) for total fruit, 0.84 (0.77-0.91) for cruciferous vegetables, 0.79 (0.68-0.91) for citrus fruits, and 0.74 (0.66-0.84) for yellow-orange vegetables. Subgroup analysis showed study design and gender as possible sources of heterogeneity. A nonlinear relationship was found of citrus fruits intake with risk of bladder cancer (P for nonlinearity = 0.018), and the RRs (95 % CI) of bladder cancer were 0.87 (0.78-0.96), 0.80 (0.67-0.94), 0.79 (0.66-0.94), 0.79 (0.65-0.96), and 0.79 (0.64-0.99) for 30, 60, 90, 120, and 150 g/day. A nonlinear relationship was also found of yellow-orange vegetable intake with risk of bladder cancer risk (P for nonlinearity = 0.033). Some evidence of publication bias was observed for fruit, citrus fruits, and yellow-orange vegetables.

CONCLUSION

This meta-analysis supports the hypothesis that intakes of fruit and vegetables may reduce the risk of bladder cancer. Future well-designed studies are required to confirm this finding.

Fruit, vegetable, and fiber intake in relation to cancer risk: findings from the European Prospective Investigation into Cancer and Nutrition (EPIC)

Fruit, vegetables, and certain components of plant foods, such as fiber, have long been thought to protect against cancer. The European Prospective Investigation into Cancer and Nutrition (EPIC) is a prospective cohort that includes >500,000 participants from 10 European countries and has made a substantial contribution to knowledge in this research area. The purpose of this article is to summarize the findings published thus far from the EPIC study on the associations between fruit, vegetable, or fiber consumption and the risk of cancer at 14 different sites. The risk of cancers of the upper gastrointestinal tract was inversely associated with fruit intake but was not associated with vegetable intake. The risk of colorectal cancer was inversely associated with intakes of total fruit and vegetables and total fiber, and the risk of liver cancer was also inversely associated with the intake of total fiber. The risk of cancer of the lung was inversely associated with fruit intake but was not associated with vegetable intake; this association with fruit intake was restricted to smokers and might be influenced by residual confounding due to smoking. There was a borderline inverse association of fiber intake with breast cancer risk. For the other 9 cancer sites studied (stomach, biliary tract, pancreas, cervix, endometrium, prostate, kidney, bladder, and lymphoma) there were no reported significant associations of risk with intakes of total fruit, vegetables, or fiber.

Citrus fruit intake and bladder cancer risk: a meta-analysis of observational studies

Epidemiological studies have investigated the association between citrus fruit and bladder cancer risk; however, the results are inconsistent. To assess these issues, we conducted a meta-analysis of currently available studies. We identified relevant articles by searching the MEDLINE and EMBASE databases. We calculated the summary relative risk (RR) with 95% confidence interval (95% CI) using a random effect model. We included eight case-control studies and six cohort studies in the meta-analysis. There was a significant inverse association between citrus fruit intake and bladder cancer risk in all pooled studies (RR: 0.85; 95% CI, 0.76-0.94) and case-control studies (RR: 0.77; 95% CI, 0.64-0.92), but not in the cohort studies (RR: 0.96; 95% CI, 0.87-1.07). Our results suggest that citrus fruit intake is related to decreased bladder cancer risk. Subsequent well-designed, large prospective studies are needed to obtain better understanding of this relationship.

Adherence to the Mediterranean diet and risk of bladder cancer in the EPIC cohort study

There is growing evidence of the protective role of the Mediterranean diet (MD) on cancer. However, to date no epidemiological study has investigated the influence of the MD on bladder cancer. We evaluated the association between adherence to the MD and risk of urothelial cell bladder cancer (UCC), according to tumor aggressiveness, in the European Prospective Investigation into Cancer and Nutrition (EPIC). The analysis included 477,312 participants, recruited from ten European countries between 1991 and 2000. Information from validated dietary questionnaires was used to develop a relative Mediterranean diet score (rMED), including nine dietary components. Cox regression models were used to assess the effect of the rMED on UCC risk, while adjusting for dietary energy and tobacco smoking of any kind. Stratified analyses were performed by sex, BMI, smoking status, European region and age at diagnosis. During an average follow-up of 11 years, 1,425 participants (70.9% male) were diagnosed with a first primary UCC. There was a negative but non-significant association between a high versus low rMED score and risk of UCC overall (HR: 0.84 [95% CI 0.69, 1.03]) and risk of aggressive (HR: 0.88 [95% CI 0.61, 1.28]) and non-aggressive tumors (HR: 0.78 [95% CI 0.54, 1.14]). Although there was no effect modification in the stratified analyses, there was a significant 34% (p = 0.043) decreased risk of UCC in current smokers with a high rMED score. In EPIC, the MD was not significantly associated with risk of UCC, although we cannot exclude that a MD may reduce risk in current smokers.

Fruit and vegetable intakes are associated with lower risk of bladder cancer among women in the Multiethnic Cohort Study

Fruits and vegetables have been examined for their possible effects on the risk of bladder cancer, as they contain numerous nutrients, phytochemicals, and antioxidants with potentially anticarcinogenic properties. In a prospective analysis of 185,885 older adults participating in the Multiethnic Cohort Study, we examined whether the consumption of fruits and vegetables, or of nutrients concentrated in fruits and vegetables, was associated with bladder cancer risk. Cox proportional hazards models were used to calculate HRs and 95% CIs for bladder cancer in relation to dietary intakes. A total of 581 invasive bladder cancer cases (429 men and 152 women) were diagnosed over a mean follow-up period of 12.5 y. In women, total fruits and vegetables [HR = 0.35 (95% CI: 0.22, 0.56); highest vs. lowest quartile], total vegetables [HR = 0.49 (95% CI: 0.29, 0.83)], yellow-orange vegetables [HR = 0.48 (95% CI: 0.30, 0.77)], total fruits [HR = 0.54 (95% CI: 0.34, 0.85)], and citrus fruits [HR = 0.56 (95% CI: 0.34, 0.90)] were inversely associated with the risk of invasive bladder cancer in risk factor-adjusted models. In addition, women with the highest intakes of vitamins A, C, and E; the carotenoids α-carotene, β-carotene, and β-cryptoxanthin; and folate had a lower risk of bladder cancer. For men, no associations for fruits, vegetables, or nutrients were found overall, although inverse associations were observed for vegetable intake among current smokers, and in ethnic-specific analyses, for fruit and vegetable intake among Latinos specifically. Our findings suggest that greater consumption of fruits and vegetables may lower the risk of invasive bladder cancer among women and highlight the need for specific subgroup analyses in future studies.

Plasma carotenoids and vitamin C concentrations and risk of urothelial cell carcinoma in the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Published associations between dietary carotenoids and vitamin C and bladder cancer risk are inconsistent. Biomarkers may provide more accurate measures of nutrient status.

OBJECTIVE

We investigated the association between plasma carotenoids and vitamin C and risk of urothelial cell carcinoma (UCC) in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition.

DESIGN

A total of 856 patients with newly diagnosed UCC were matched with 856 cohort members by sex, age at baseline, study center, date and time of blood collection, and fasting status. Plasma carotenoids (α- and β-carotene, β-cryptoxanthin, lycopene, lutein, and zeaxanthin) were measured by using reverse-phase HPLC, and plasma vitamin C was measured by using a colorimetric assay. Incidence rate ratios (IRRs) were estimated by using conditional logistic regression with adjustment for smoking status, duration, and intensity.

RESULTS

UCC risk decreased with higher concentrations of the sum of plasma carotenoids (IRR for the highest compared with the lowest quartile: 0.64; 95% CI: 0.44, 0.93; P-trend = 0.04). Plasma β-carotene was inversely associated with aggressive UCC (IRR: 0.51; 95% CI: 0.30, 0.88; P-trend = 0.02). Plasma lutein was inversely associated with risk of nonaggressive UCC (IRR: 0.56; 95% CI: 0.32, 0.98; P-trend = 0.05). No association was observed between plasma vitamin C and risk of UCC.

CONCLUSIONS

Although residual confounding by smoking or other factors cannot be excluded, higher concentrations of plasma carotenoids may reduce risk of UCC, in particular aggressive UCC. Plasma lutein may reduce risk of nonaggressive UCC.

Fruit and vegetable consumption and risk of aggressive and non-aggressive urothelial cell carcinomas in the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Many epidemiological studies have examined fruit and vegetable consumption in relation to the risk of urothelial cell carcinoma (UCC) of the bladder, but results are inconsistent. The association between fruit and vegetable consumption and UCC risk may vary by bladder tumour aggressiveness. Therefore, we examined the relation between fruit and vegetable consumption and the risk of aggressive and non-aggressive UCC in the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

After 8.9 years of follow-up, 947UCC were diagnosed among 468,656 EPIC participants. Of these, 421 could be classified as aggressive UCC and 433 as non-aggressive UCC cases. At recruitment, fruit and vegetable consumption was assessed by validated dietary questionnaires. Multivariable hazard ratios were estimated using Cox regression stratified by age, sex and center and adjusted for smoking status, duration and intensity of smoking, and energy intake.

RESULTS

Total consumption of fruits and vegetables was not associated with aggressive UCC nor with non-aggressive UCC. A 25 g/day increase in leafy vegetables and grapes consumption was associated with a reduced risk of non-aggressive UCC (hazard ratio (HR) 0.88; 95%confidence interval (CI) 0.78-1.00 and HR 0.87; 95%CI 0.77-0.98, respectively), while the intake of root vegetables was inversely associated with risk of aggressive UCC (HR 0.87; 95%CI 0.77-0.98).

CONCLUSION

Our study did not confirm a protective effect of total fruit and/or vegetable consumption on aggressive or non-aggressive UCC. High consumption of certain types of vegetables and of fruits may reduce the risk of aggressive or non-aggressive UCC; however chance findings cannot be excluded.

Is concordance with World Cancer Research Fund/American Institute for Cancer Research guidelines for cancer prevention related to subsequent risk of cancer? Results from the EPIC study

BACKGROUND

In 2007 the World Cancer Research Fund (WCRF) and the American Institute of Cancer Research (AICR) issued 8 recommendations (plus 2 special recommendations) on diet, physical activity, and weight management for cancer prevention on the basis of the most comprehensive collection of available evidence.

OBJECTIVE

We aimed to investigate whether concordance with the WCRF/AICR recommendations was related to cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

DESIGN

The present study included 386,355 EPIC participants from 9 European countries. At recruitment, dietary, anthropometric, and lifestyle information was collected. A score was constructed based on the WCRF/AICR recommendations on weight management, physical activity, foods and drinks that promote weight gain, plant foods, animal foods, alcoholic drinks, and breastfeeding for women; the score range was 0-6 for men and 0-7 for women. Higher scores indicated greater concordance with WCRF/AICR recommendations. The association between the score and cancer risk was estimated by using multivariable Cox regression models.

RESULTS

Concordance with the score was significantly associated with decreased risk of cancer. A 1-point increment in the score was associated with a risk reduction of 5% (95% CI: 3%, 7%) for total cancer, 12% (95% CI: 9%, 16%) for colorectal cancer, and 16% (95% CI: 9%, 22%) for stomach cancer. Significant associations were also observed for cancers of the breast, endometrium, lung, kidney, upper aerodigestive tract, liver, and esophagus but not for prostate, ovarian, pancreatic, and bladder cancers.

CONCLUSION

Adherence to the WCRF/AICR recommendations for cancer prevention may lower the risk of developing most types of cancer.

Nutrigenomics: implications for breast and colon cancer prevention

Nutrigenomics refers to the interaction between one's diet and his/her genes. These interactions can markedly influence digestion, absorption, and the elimination of bioactive food components, as well as influence their site of actions/molecular targets. Nutrigenomics comprises nutrigenetics, epigenetics, and transcriptomics, coupled with other "omic," such as proteomics and metabolomics, that apparently account for the wide variability in cancer risk among individuals with similar dietary habits. Multiple food components including essential nutrients, phytochemical, zoochemicals, fungochemical, and bacterochemicals have been implicated in cancer risk and tumor behavior, admittedly with mixed results. Such findings suggest that not all individuals respond identically to a diet. This chapter highlights the influence of single-nucleotide polymorphism, copy number, epigenetic events, and transcriptomic homeostasis as factors influencing the response to food components and ultimately health, including cancer risk. Both breast and colorectal cancers are reviewed as examples about how nutrigenomics may influence the response to dietary intakes. As the concept that "one size fits all" comes to an end and personalized approaches surface, additional research data will be required to identify those who will benefit most from dietary change and any who might be placed at risk because of an adjustment.

Quercetin and cancer chemoprevention

Several molecules present in the diet, including flavonoids, can inhibit the growth of cancer cells with an ability to act as "chemopreventers". Their cancer-preventive effects have been attributed to various mechanisms, including the induction of cell-cycle arrest and/or apoptosis as well as the antioxidant functions. The antioxidant activity of chemopreventers has recently received a great interest, essentially because oxidative stress participates in the initiation and progression of different pathological conditions, including cancer. Since antioxidants are capable of preventing oxidative damage, the wide use of natural food-derived antioxidants is receiving greater attention as potential anti-carcinogens. Among flavonoids, quercetin (Qu) is considered an excellent free-radical scavenging antioxidant, even if such an activity strongly depends on the intracellular availability of reduced glutathione. Apart from antioxidant activity, Qu also exerts a direct, pro-apoptotic effect in tumor cells, and can indeed block the growth of several human cancer cell lines at different phases of the cell cycle. Both these effects have been documented in a wide variety of cellular models as well as in animal models. The high toxicity exerted by Qu on cancer cells perfectly matches with the almost total absence of any damages for normal, non-transformed cells. In this review we discuss the molecular mechanisms that are based on the biological effects of Qu, and their relevance for human health.

Red Meat, Dietary Nitrosamines, and Heme Iron and Risk of Bladder Cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Background: Previous epidemiologic studies found inconsistent results for the association between red meat intake, nitrosamines [NDMA: N-nitrosodimethylamine, and ENOC (endogenous nitroso compounds)], and the risk of bladder cancer. We investigated the association between red meat consumption, dietary nitrosamines, and heme iron and the risk of bladder cancer among participants of the European Prospective Investigation into Cancer and Nutrition (EPIC).

Methods: Data on food consumption and complete follow-up for cancer occurrence were available for a total of 481,419 participants, recruited in 10 European countries. Estimates of HRs were obtained by proportional hazard models, stratified by age at recruitment, gender, and study center and adjusted for total energy intake, smoking status, lifetime intensity of smoking, duration of smoking, educational level, and BMI.

Results: After a mean follow-up of 8.7 years, 1,001 participants were diagnosed with bladder cancer. We found no overall association between intake of red meat (log2 HR: 1.06; 95% CI: 0.99–1.13), nitrosamines (log2 HR: 1.09; 95% CI: 0.92–1.30 and HR: 0.98; 95% CI: 0.92–1.05 for ENOC and NDMA, respectively) or heme iron

(log2 HR: 1.05; 95 CI: 0.99–1.12) and bladder cancer risk. The associations did not vary by sex, high- versus low-risk bladder cancers, smoking status, or occupation (high vs. low risk).

Conclusions: Our findings do not support an effect of red meat intake, nitrosamines (endogenous or exogenous), or heme iron intake on bladder cancer risk. Cancer Epidemiol Biomarkers Prev; 20(3); 555–9. ©2011 AACR.

Dietary flavonoids as cancer prevention agents

Dietary agents identified from fruits and vegetables contribute to keeping balanced cell proliferation and preventing cell carcinogenesis. Dietary flavonoids, combined with other components such as various vitamins, play an important role in cancer prevention. Flavonoids act on reactive oxygen species, cell signal transduction pathways related to cellular proliferation, apoptosis, and angiogenesis. Many studies demonstrate that flavonoids are responsible for chemoprevention, although mechanisms of action remain to be investigated. Overall, exciting data show that dietary flavonoids could be considered as a useful cancer preventive approach. This review summarizes recent advancements on potential cancer preventive effects and mechanic insight of dietary flavonoids.

Fruit and vegetable intake and overall cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC)

BACKGROUND

It is widely believed that cancer can be prevented by high intake of fruits and vegetables. However, inconsistent results from many studies have not been able to conclusively establish an inverse association between fruit and vegetable intake and overall cancer risk.

METHODS

We conducted a prospective analysis of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to assess relationships between intake of total fruits, total vegetables, and total fruits and vegetables combined and cancer risk during 1992-2000. Detailed information on the dietary habit and lifestyle variables of the cohort was obtained. Cancer incidence and mortality data were ascertained, and hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox regression models. Analyses were also conducted for cancers associated with tobacco and alcohol after stratification for tobacco smoking and alcohol drinking.

RESULTS

Of the initial 142 605 men and 335 873 women included in the study, 9604 men and 21 000 women were identified with cancer after a median follow-up of 8.7 years. The crude cancer incidence rates were 7.9 per 1000 person-years in men and 7.1 per 1000 person-years in women. Associations between reduced cancer risk and increased intake of total fruits and vegetables combined and total vegetables for the entire cohort were similar (200 g/d increased intake of fruits and vegetables combined, HR = 0.97, 95% CI = 0.96 to 0.99; 100 g/d increased intake of total vegetables, HR = 0.98, 95% CI = 0.97 to 0.99); intake of fruits showed a weaker inverse association (100 g/d increased intake of total fruits, HR = 0.99, 95% CI = 0.98 to 1.00). The reduced risk of cancer associated with high vegetable intake was restricted to women (HR = 0.98, 95% CI = 0.97 to 0.99). Stratification by alcohol intake suggested a stronger reduction in risk in heavy drinkers and was confined to cancers caused by smoking and alcohol.

CONCLUSIONS

A very small inverse association between intake of total fruits and vegetables and cancer risk was observed in this study. Given the small magnitude of the observed associations, caution should be applied in their interpretation.