The association between meat and fish consumption and bladder cancer risk: a pooled analysis of 11 cohort studies

Common questions and misconceptions about protein supplementation: what does the scientific evidence really show?

Protein supplementation often refers to increasing the intake of this particular macronutrient through dietary supplements in the form of powders, ready-to-drink shakes, and bars. The primary purpose of protein supplementation is to augment dietary protein intake, aiding individuals in meeting their protein requirements, especially when it may be challenging to do so through regular food (i.e. chicken, beef, fish, pork, etc.) sources alone. A large body of evidence shows that protein has an important role in exercising and sedentary individuals. A PubMed search of "protein and exercise performance" reveals thousands of publications. Despite the considerable volume of evidence, it is somewhat surprising that several persistent questions and misconceptions about protein exist. The following are addressed: 1) Is protein harmful to your kidneys? 2) Does consuming "excess" protein increase fat mass? 3) Can dietary protein have a harmful effect on bone health? 4) Can vegans and vegetarians consume enough protein to support training adaptations? 5) Is cheese or peanut butter a good protein source? 6) Does consuming meat (i.e., animal protein) cause unfavorable health outcomes? 7) Do you need protein if you are not physically active? 8) Do you need to consume protein ≤ 1 hour following resistance training sessions to create an anabolic environment in skeletal muscle? 9) Do endurance athletes need additional protein? 10) Does one need protein supplements to meet the daily requirements of exercise-trained individuals? 11) Is there a limit to how much protein one can consume in a single meal? To address these questions, we have conducted a thorough scientific assessment of the literature concerning protein supplementation.

C15:0 and C17:0 partially mediate the association of milk and dairy products with bladder cancer risk

The relationship between saturated fatty acids (SFA) and bladder cancer (BC) risk has been conflicting. Our aim was to investigate the relationship between erythrocyte membrane SFA and BC risk. A total of 404 participants were enrolled in the study (including 112 cases and 292 controls). A validated food frequency questionnaire was used to assess the food intake. The constitutive composition of fatty acids in the erythrocyte membrane was measured by gas chromatography. After adjustment for BC risk factors, SFA had no significant association with BC risk. However, C18:0 was positively linked with BC risk with an odds ratio (OR; 95% CI) of 2.99 (1.37-6.53). In contrast, very-long-chain saturated fatty acids (VLCSFA), especially C24:0, were negatively related to BC risk with an OR (95% CI) of 0.28 (0.12-0.65) for VLCSFA and 0.33 (0.15-0.75) for C24:0. Higher total odd-chain SFA (C15:0 and C17:0) were associated with a lower risk of BC with OR (95% CI) of 0.18 (0.076-0.44), 0.18 (0.068-0.47), 0.34 (0.14-0.81), respectively. After subgroup analysis, the protective effects C15:0 and C17:0 were still remained. Receiver operating characteristic analysis displayed that the combination of C15:0 and C17:0 indexes increased the accurate predictive rate of BC risk. Further mediation effect analysis showed that C15:0 and C17:0 could be used as partial mediation effectors for milk and dairy products and bladder carcinogenesis. Overall, the combination of odd-chain SFA (C15:0 and C17:0) in the erythrocyte membrane could serve as a reliable mediator and predictor, indicating a relationship between a high intake of milk and dairy products and a lower risk of BC.

Epidemiology of Bladder Cancer in 2023: A Systematic Review of Risk Factors

CONTEXT

Bladder cancer (BC) is common worldwide and poses a significant public health challenge. External risk factors and the wider exposome (totality of exposure from external and internal factors) contribute significantly to the development of BC. Therefore, establishing a clear understanding of these risk factors is the key to prevention.

OBJECTIVE

To perform an up-to-date systematic review of BC's epidemiology and external risk factors.

EVIDENCE ACQUISITION

Two reviewers (I.J. and S.O.) performed a systematic review using PubMed and Embase in January 2022 and updated it in September 2022. The search was restricted to 4 yr since our previous review in 2018.

EVIDENCE SYNTHESIS

Our search identified 5177 articles and a total of 349 full-text manuscripts. GLOBOCAN data from 2020 revealed an incidence of 573 000 new BC cases and 213 000 deaths worldwide in 2020. The 5-yr prevalence worldwide in 2020 was 1 721 000. Tobacco smoking and occupational exposures (aromatic amines and polycyclic aromatic hydrocarbons) are the most substantial risk factors. In addition, correlative evidence exists for several risk factors, including specific dietary factors, imbalanced microbiome, gene-environment risk factor interactions, diesel exhaust emission exposure, and pelvic radiotherapy.

CONCLUSIONS

We present a contemporary overview of the epidemiology of BC and the current evidence for BC risk factors. Smoking and specific occupational exposures are the most established risk factors. There is emerging evidence for specific dietary factors, imbalanced microbiome, gene-external risk factor interactions, diesel exhaust emission exposure, and pelvic radiotherapy. Further high-quality evidence is required to confirm initial findings and further understand cancer prevention.

PATIENT SUMMARY

Bladder cancer is common, and the most substantial risk factors are smoking and workplace exposure to suspected carcinogens. On-going research to identify avoidable risk factors could reduce the number of people who get bladder cancer.

Dietary vitamin D intake and the bladder cancer risk: A pooled analysis of prospective cohort studies

BACKGROUND & AIMS

Diet may play an essential role in the aetiology of bladder cancer (BC). Vitamin D is involved in various biological functions which have the potential to prevent BC development. Besides, vitamin D also influences the uptake of calcium and phosphorus, thereby possibly indirectly influencing the risk of BC. The aim of the present study was to investigate the relation between vitamin D intake and BC risk.

METHODS

Individual dietary data were pooled from ten cohort studies. Food item intake was converted to daily intakes of vitamin D, calcium and phosphorus. Pooled multivariate hazard ratios (HRs), with corresponding 95% confidence intervals (CIs) were obtained using Cox-regression models. Analyses were adjusted for gender, age and smoking status (Model 1), and additionally for the food groups fruit, vegetables and meat (Model 2). Dose-response relationships (Model 1) were examined using a nonparametric test for trend.

RESULTS

In total, 1994 cases and 518,002 non-cases were included in the analyses. The present study showed no significant associations between individual nutrient intake and BC risk. A significant decreased BC risk was observed for high vitamin D intake with moderate calcium and low phosphorus intake (Model 2: HR_{high vitD, mod Ca, low P}: 0.77, 95% CI: 0.59-1.00). No significant dose-response analyses were observed.

CONCLUSION

The present study showed a decreased BC risk for high dietary vitamin D intake in combination with low calcium intake and moderate phosphorus intake. The study highlights the importance of examining the effect of a nutrient in combination with complementary nutrients for risk assessment. Future research should focus on nutrients in a wider context and in nutritional patterns.

Food groups and urologic cancers risk: a systematic review and meta-analysis of prospective studies

Background

To assess the association between 12 food groups intake and the risk of urologic cancers.

Methods

We scanned PubMed and Web of Science databases up to April 1st, 2023, and 73 publications met the inclusion criteria in the meta-analysis. We used a random effects model to estimate the summary risk ratios (RRs) and 95% confidence intervals (95% CI).

Results

In the linear dose-response meta-analysis, an inverse association was found between each additional daily 100 g of fruits [RR: 0.89, 95%CI = (0.83, 0.97)], 100 g of vegetables [RR: 0.92, 95%CI = (0.85, 0.99)], 12 g of alcohol [RR: 0.91, 95%CI = (0.88, 0.94)] and 1 cup of coffee [RR: 0.95, 95%CI = (0.83, 0.97)] intake and the risk of renal cell carcinoma. Conversely, each additional daily 100 g of red meat intake was positively associated with renal cell carcinoma [RR: 1.41, 95%CI = (1.03, 2.10)]. Inverse associations were observed between each additional daily 50 g of egg [RR: 0.73, 95%CI = (0.62, 0.87)] and each additional daily 1 cup of tea consumption and bladder cancer risk [RR: 0.97, 95%CI = (0.94, 0.99)]. There were no significant associations for nonlinear dose-response relationships between 12 food groups and urological cancers.

Conclusion

Our meta-analysis strengthens the evidence that appropriate intake of specific food groups, such as fruits, vegetables, alcohol, tea, and coffee, is associated with the risk of renal cell carcinoma or bladder cancer. More studies are required to fill the knowledge gap on the links between various food groups and urologic cancers because the evidence was less credible in this meta-analysis.

Systematic Review Registration

This study was registered on PROSPERO (CRD42022340336).

Meat Intake and the Risk of Bladder Cancer: A Systematic Review and Meta-Analysis of Observational Studies

The evidence for the association between meat intake and the risk of bladder cancer (BC) is still inconclusive. A total of 29 studies involving 1,475,125 participants and 18,836 cases of BC were included in the meta-analysis. Among these studies, 11 reported total meat intake, 20 reported red meat intake, 19 reported processed meat intake, 15 reported white meat intake, and 15 reported fish intake. The results suggested that there was an overall increase in BC risk associated with total meat intake (RR = 1.10; 95% confidence interval: 0.92-1.31; I² = 55.20%; P = 0.014), and a higher red meat (RR = 1.23; 95% CI: 1.08-1.39; I² = 51.30%; P = 0.004) or processed meat (RR = 1.16; 95% CI: 1.08-1.25; I² = 28.00%; P = 0.125) intake may increase the risk of BC. In contrast, a higher intake of fish (RR = 0.80; 95% CI: 0.67-0.95; I² = 62.90%; P = 0.001) was inversely associated with the risk of BC. Moreover, we did not observe an association between white meat (RR = 0.96; 95% CI: 0.83-1.10; I² = 53.70%; P = 0.007) and the risk of BC. Our findings suggested that dietary intervention may be an effective approach to preventing BC, which still needs to be confirmed by further well-designed observational studies.

Epidemiology, Screening, and Prevention of Bladder Cancer

CONTEXT

Bladder cancer (BC) represents a significant health problem due to the potential morbidity and mortality associated with disease burden, which has remained largely unaltered over time.

OBJECTIVE

To provide an expert collaborative review and describe the incidence, prevalence, and mortality of BC and to evaluate current evidence for BC screening and prevention.

EVIDENCE ACQUISITION

Data on the estimated incidence and mortality of BC for 2020 in 185 countries were derived from the International Agency for Research on Cancer GLOBOCAN database. A review of English-language articles published over the past 5 yr was conducted using PubMed/MEDLINE to identify risk factors in addition to contemporary evidence on BC screening and prevention.

EVIDENCE SYNTHESIS

BC is the tenth most common cancer worldwide, with 573 278 cases in 2020. BC incidence is approximately fourfold higher in men than women. Tobacco smoking remains the principal risk factor, accounting for approximately 50% of cases. There is insufficient evidence to recommend routine BC screening. However, targeted screening of high-risk individuals (defined according to smoking history or occupational exposure) may reduce BC mortality and should be the focus of prospective randomized trials. In terms of disease prevention, smoking cessation represents the most important intervention, followed by a reduction in exposure to occupational and environmental carcinogens.

CONCLUSIONS

BC confers a significant disease burden. An understanding of BC epidemiology and risk factors provides an optimal foundation for disease prevention and the care of affected patients.

PATIENT SUMMARY

Bladder cancer is the tenth most common cancer worldwide and is approximately four times more common among men than among women. The main risk factors are tobacco smoking, followed by exposure to carcinogens in the workplace or the environment. Routine screening is not currently recommended, but may be beneficial in individuals at high risk, such as heavy smokers. Primary prevention is extremely important, and smoking cessation represents the most important action for reducing bladder cancer cases and deaths.

Dietary B group vitamin intake and the bladder cancer risk: a pooled analysis of prospective cohort studies

PURPOSE

Diet may play an essential role in the aetiology of bladder cancer (BC). The B group complex vitamins involve diverse biological functions that could be influential in cancer prevention. The aim of the present study was to investigate the association between various components of the B group vitamin complex and BC risk.

METHODS

Dietary data were pooled from four cohort studies. Food item intake was converted to daily intakes of B group vitamins and pooled multivariate hazard ratios (HRs), with corresponding 95% confidence intervals (CIs), were obtained using Cox-regression models. Dose-response relationships were examined using a nonparametric test for trend.

RESULTS

In total, 2915 BC cases and 530,012 non-cases were included in the analyses. The present study showed an increased BC risk for moderate intake of vitamin B1 (HRB1: 1.13, 95% CI: 1.00-1.20). In men, moderate intake of the vitamins B1, B2, energy-related vitamins and high intake of vitamin B1 were associated with an increased BC risk (HR (95% CI): 1.13 (1.02-1.26), 1.14 (1.02-1.26), 1.13 (1.02-1.26; 1.13 (1.02-1.26), respectively). In women, high intake of all vitamins and vitamin combinations, except for the entire complex, showed an inverse association (HR (95% CI): 0.80 (0.67-0.97), 0.83 (0.70-1.00); 0.77 (0.63-0.93), 0.73 (0.61-0.88), 0.82 (0.68-0.99), 0.79 (0.66-0.95), 0.80 (0.66-0.96), 0.74 (0.62-0.89), 0.76 (0.63-0.92), respectively). Dose-response analyses showed an increased BC risk for higher intake of vitamin B1 and B12.

CONCLUSION

Our findings highlight the importance of future research on the food sources of B group vitamins in the context of the overall and sex-stratified diet.

Dietary fats and their sources in association with the risk of bladder cancer: A pooled analysis of 11 prospective cohort studies

The effects of fat intake from different dietary sources on bladder cancer (BC) risk remains unidentified. Therefore, the present study aimed to investigate the association between fat intakes and BC risk by merging world data on this topic. Data from 11 cohort studies in the BLadder cancer Epidemiology and Nutritional Determinants (BLEND) study, provided sufficient information on fat intake for a total of 2731 BC cases and 544 452 noncases, which yielded 5 400 168 person-years of follow-up. Hazard ratios (HRs), with corresponding 95% confidence intervals (CIs), were estimated using Cox-regression models stratified on cohort. Analyses were adjusted for total energy intake in kilocalories, gender, smoking status (model-1) and additionally for sugar and sugar products, beers, wine, dressing and plant-based and fruits intakes (model-2). Among women, an inverse association was observed between mono-unsaturated fatty acids (MUFAs) and BC risk (HR comparing the highest with the lowest tertile: 0.73, 95% CI: 0.58-0.93, P-trend = .01). Overall, this preventative effect of MUFAs on BC risk was only observed for the nonmuscle invasive bladder cancer (NMIBC) subtype (HR: 0.69, 95% CI: 0.53-0.91, P-trend = .004). Among men, a higher intake of total cholesterol was associated with an increased BC risk (HR: 1.37, 95% CI: 1.16-1.61, P-trend = .01). No other significant associations were observed. This large prospective study adds new insights into the role of fat and oils in BC carcinogenesis, showing an inverse association between consumption of MUFAs and the development of BC among women and a direct association between higher intakes of dietary cholesterol and BC risk among men.

Genesis and Mechanism of Some Cancer Types and an Overview on the Role of Diet and Nutrition in Cancer Prevention

Cancer is a major disease with a high mortality rate worldwide. In many countries, cancer is considered to be the second most common cause of death after cardiovascular disease. The clinical management of cancer continues to be a challenge as conventional treatments, such as chemotherapy and radiation therapy, have limitations due to their toxicity profiles. Unhealthy lifestyle and poor dietary habits are the key risk factors for cancer; having a healthy diet and lifestyle may minimize the risk. Epidemiological studies have shown that a high fruit and vegetable intake in our regular diet can effectively reduce the risk of developing certain types of cancers due to the high contents of antioxidants and phytochemicals. In vitro and in vivo studies have shown that phytochemicals exert significant anticancer effects due to their free radical scavenging capacity potential. There has been extensive research on the protective effects of phytochemicals in different types of cancers. This review attempts to give an overview of the etiology of different types of cancers and assesses the role of phytonutrients in the prevention of cancers, which makes the present review distinct from the others available.