Alcohol consumption and its association with cancer, cardiovascular, liver and brain diseases: a systematic review of Mendelian randomization studies

Background

The health effects of alcohol consumption, particularly regarding potential protective benefits of light to moderate intake compared to abstinence, remain a subject of ongoing debate. However, epidemiological studies face limitations due to imprecise exposure measurements and the potential for bias through residual confounding and reverse causation. To address these limitations, we conducted a systematic review of Mendelian Randomization (MR) studies examining the causal relationship between alcohol consumption and cancers, cardiovascular, liver, and neurological diseases.

Methodology

We searched PubMed, ScienceDirect and Embase and Europe PMC up to 05/2024 for MR studies investigating the association of genetically predicted alcohol consumption with cancers, cardiovascular, liver and neurological diseases. We assessed methodological quality based on key elements of the MR design a genetic association studies tool.

Results

We included 70 MR studies that matched our inclusion criteria. Our review showed a significant association of alcohol consumption with multiple cancers such as oral and oropharyngeal, esophageal, colorectal cancers, hepatocellular carcinoma and cutaneous melanoma. While the available studies did not consistently confirm the adverse or protective effects of alcohol on other cancers, such as lung cancer, as suggested by observational studies. Additionally, MR studies confirmed a likely causal effect of alcohol on the risk of hypertension, atrial fibrillation, myocardial infraction and vessels disease. However, there was no evidence to support the protective effects of light to moderate alcohol consumption on cognitive function, Alzheimer's disease, and amyotrophic lateral sclerosis, as reported in observational studies while our review revealed an increased risk of epilepsy and multiple sclerosis. The available studies provided limited results on the link between alcohol consumption and liver disease.

Conclusions

Despite the valuable insights into the causal relationship between alcohol consumption and various health outcomes that MR studies provided, it is worth noting that the inconsistent ability of genetic instrumental variables to distinguish between abstainers, light and moderate drinkers makes it difficult to differentiate between U or J-shaped vs. linear relationships between exposure and outcome. Additional research is necessary to establish formal quality assessment tools for MR studies and to conduct more studies in diverse populations, including non-European ancestries.

Systematic Review Registration

www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021246154, Identifier: PROSPERO (CRD42021246154).

Gut and bladder fermentation syndromes: a narrative review

We recently reported the first clinical case of bladder fermentation syndrome (BFS) or urinary auto-brewery syndrome, which caused the patient to fail abstinence monitoring. In BFS, ethanol is generated by Crabtree-positive fermenting yeast Candida glabrata in a patient with poorly controlled diabetes. One crucial characteristic of BFS is the absence of alcoholic intoxication, as the bladder lumen contains transitional epithelium with low ethanol permeability. In contrast, patients with gut fermentation syndrome (GFS) or auto-brewery syndrome can spontaneously develop symptoms of ethanol intoxication even without any alcohol ingestion because of alcoholic fermentation in the gut lumen. In abstinence monitoring, a constellation of laboratory findings with positive urinary glucose and ethanol, negative ethanol metabolites, and the presence of yeast in urinalysis should raise suspicion for BFS, whereas endogenous ethanol production needs to be shown by a carbohydrate challenge test for GFS diagnosis. GFS patients will also likely fail abstinence monitoring because of the positive ethanol blood testing. BFS and GFS are treated by yeast eradication of fermenting microorganisms with antifungals (or antibiotics for bacterial GFS cases) and modification of underlying conditions (diabetes for BFS and gut dysbiosis for GFS). The under-recognition of these rare medical conditions has led to not only harm but also adverse legal consequences for patients, such as driving under the influence (DUI). GFS patients may be at risk of various alcohol-related diseases.

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).

Moderate wine consumption and cancer risk in context

There is no doubt that excessive consumption of alcoholic beverages and binge drinking patterns increase the risk for cancer and many other diseases. Regarding the safety of light to moderate consumption of wine/alcoholic beverages, however, mixed messages exist. For decades, the potential health benefits of moderate wine consumption have been consistently shown, in particular for reducing cardiovascular mortality and morbidity. On the other hand, some population studies suggested that there is no safe limit of alcohol and ANY consumption is harmful to health, because of an increased cancer risk. Cancer is a multifactorial disease and it is increasingly accepted that certain lifestyle choices can affect the risk of developing cancer. Individuals do not drink only wine/alcoholic beverages, they eat different foods and have particular lifestyle habits. Besides several unmodifiable risk factors (age, sex, ethnicity and genetic disposition), improving lifestyle habits may contribute to reduce the risk of cancer. According to the World Health Organisation (WHO) and the World Cancer Research Fund (WCRF), one third of the cancers could be prevented by adopting a healthy lifestyle (such as avoiding smoking, maintaining a normal body weight, being physically active, avoiding excessive consumption of alcoholic beverages and keeping a healthy dietary pattern). Furthermore, the Mediterranean Diet is considered as one of the healthiest in the world by the WHO and is directly associated with a lower rate of mortality thanks to its effects on disease prevention. However, moderate consumption of wine is an important component of that diet. So recommendations for a healthy lifestyle which include a healthy, balanced diet and avoidance of any alcoholic beverage may be confusing. Can moderate wine drinkers still enjoy a glass of wine with the meal without jeopardizing their health? A detailed analysis of the scientific evidence will be provided and the risk of moderate wine consumption within the context of lifestyle will be examined.

The causal association between smoking, alcohol consumption and risk of bladder cancer: A univariable and multivariable Mendelian randomization study

Smoking and alcohol consumption are associated with bladder cancer risk in observational studies. We conducted a two-sample univariable and multivariable Mendelian randomization (MR) analysis to determine whether those associations are causal. We used 21, 126, 360, 39 single nucleotide polymorphisms (SNPs) as instrumental variables for number of cigarettes per day, lifetime smoking index, smoking initiation, and drinks per week, respectively. A total of 1115 cases with bladder cancer and 174 006 noncases from FinnGen consortium and 2883 cases with bladder cancer and 417 955 noncases from UK Biobank study were obtained. Genetic predisposition to cigarettes per day, lifetime smoking index and smoking initiation were positively associated with an increased risk of bladder cancer in both the FinnGen and UK Biobank consortium. The summary odds ratio (OR) of bladder cancer was 1.79 (95% confidence interval [CI], 1.31-2.45; P = .0002), 2.38 (95% CI, 1.45-3.88; P = .0005) and 1.91 (95% CI, 1.46-2.50; P = 1.59 × 10-06 ) for one SD increase in the number of cigarettes per day, lifetime smoking index and smoking initiation, respectively. The genetically instrumented number of drinks per week was not associated with bladder cancer (OR = 0.69; 95% CI, 0.44-1.10; P = .1237). Estimates were consistent in multivariable MR analyses by the adjustments of body mass index and education. Our study suggests a causal potential of the association of smoking but not alcohol consumption with bladder cancer according to current evidence.

Burden of Cancer Due to Cigarette Smoking and Alcohol Consumption in Korea

This study aimed to estimate the burden of cancer in Koreans attributable to smoking and alcohol consumption using disability-adjusted life years and population attributable fractions. We estimated the burden of 12 cancers due to simultaneous and independent smoking and alcohol exposure in Koreans aged ≥40 years. In men, the cancer burden attributable to the combined risk factors, smoking alone, and alcohol consumption alone were 9.5, 14.8, and 6.1%, respectively; the corresponding values for women were 1.1, 2.5, and 2.7%, respectively. In men, tracheal, bronchial, and lung cancers were the most common cancer types. The disease burden may have been reduced by 16.8, 32.3, and 4.1% in the absence of the combined risk factors, smoking alone, and alcohol consumption alone, respectively. Our findings suggest that risk factor-based intervention may have the greatest preventative effect for lung cancer among all cancers in men. Our real-world data methodology could provide further evidence-based methods to explore and facilitate effective health promotion interventions for specific target groups and may lay the foundation for the establishment of healthcare services according to population subgroups or regional characteristics.

Association Between Alcohol Consumption and Risk of Bladder Cancer: A Dose-Response Meta-Analysis of Prospective Cohort Studies

Background

Controversial results of the association between alcohol consumption and risk of bladder cancer were reported by the previous meta-analyses.

Objective

To quantitatively investigate the association between alcohol consumption and risk of bladder cancer based on prospective cohort studies, and explore whether there is potential dose-response relation.

Method

PubMed, EMBASE, the Cochrane Library databases, China Biology Medicine disc (CBM), and Chinese National Knowledge Infrastructure (CNKI) were searched for relevant studies. Categorical meta-analysis was performed for risk estimates of any alcohol consumers versus non-drinkers as well as different drinking degrees (light, moderate, and heavy) versus none. And two-stage generalized least-squares regression and restricted cubic spline, as well as fixed-effects dose-response models, were used for linear and nonlinear dose-response relation exploration.

Results

9 prospective cohort studies including 1,971,396 individuals were finally included. We did not observe a significant association between alcohol intake and the risk of bladder cancer in the entire population. Linear association was detected in those who consumed alcohol from liquor or spirits (P _linear=0.02). One drink increment each day of alcohol could elevate the risk of bladder cancer by 9% (RR=1.09; 95%CI: 1.01-1.17). Alcohol was a risk factor of bladder cancer for male drinkers (RR=1.23; 95%CI: 1.13-1.35; I²=3.7%), while none linear or nonlinear relation was found.

Conclusion

No significant association between alcohol consumption and bladder cancer risk was found in the entire population, but there was a linear dose-response relation in those who consume alcohol from liquor or spirits. Alcohol may elevate the risk of bladder cancer in males in a dose-independent way.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, PROSPERO (CRD42020216195).

Alcohol Use Disorders and Their Harmful Effects on the Contractility of Skeletal, Cardiac and Smooth Muscles

Alcohol misuse has deleterious effects on personal health, family, societal units, and global economies. Moreover, alcohol misuse usually leads to several diseases and conditions, including alcoholism, which is a chronic condition and a form of addiction. Alcohol misuse, whether as acute intoxication or alcoholism, adversely affects skeletal, cardiac and/or smooth muscle contraction. Ethanol (ethyl alcohol) is the main effector of alcohol-induced dysregulation of muscle contractility, regardless of alcoholic beverage type or the ethanol metabolite (with acetaldehyde being a notable exception). Ethanol, however, is a simple and "promiscuous" ligand that affects many targets to mediate a single biological effect. In this review, we firstly summarize the processes of excitation-contraction coupling and calcium homeostasis which are critical for the regulation of contractility in all muscle types. Secondly, we present the effects of acute and chronic alcohol exposure on the contractility of skeletal, cardiac, and vascular/ nonvascular smooth muscles. Distinctions are made between in vivo and in vitro experiments, intoxicating vs. sub-intoxicating ethanol levels, and human subjects vs. animal models. The differential effects of alcohol on biological sexes are also examined. Lastly, we show that alcohol-mediated disruption of muscle contractility, involves a wide variety of molecular players, including contractile proteins, their regulatory factors, membrane ion channels and pumps, and several signaling molecules. Clear identification of these molecular players constitutes a first step for a rationale design of pharmacotherapeutics to prevent, ameliorate and/or reverse the negative effects of alcohol on muscle contractility.

Light Alcohol Drinking and the Risk of Cancer Development: A Controversial Relationship

BACKGROUND

In accordance with the scientific literature heavy alcohol consumption (>50g per day) represents a risk factor for several diseases development, including cancer. However, the oncogenic role of light alcohol drinking (<12.5g per day) is still unknown.

OBJECTIVE

To assess the scientific knowledge about light alcohol consumption and the risk of malignancy onset.

METHODS

To collect the scientific evidences regarding this topic the keywords "light alcohol drinking", "light alcohol consumption" and "cancer", were used. Papers published during the last 15 years were analyzed, in order to select the most recent evidence. Meta-analyses with well-defined levels of alcohol intake were included in the present review. Other studies that focused on biochemical, molecular and genetic aspects, as well as duplicate articles, were excluded.

RESULTS

Twenty-nine large, meta-analyses were included in this review. Light alcohol drinking was not associated with an increased risk of cancer occurrence, with the exception of breast and prostate cancer and melanoma. Furthermore, a possible protective role of light alcohol consumption on the development of bladder, kidney and ovarian cancer and Non Hodgkin Lymphoma was observed.

CONCLUSION

Light alcohol drinking was not associated with the development of several malignancies, except for a light increase of melanoma, breast cancer in women and prostate cancer in men.

Fluid intake and clinicopathological characteristics of bladder cancer: the West Midlands Bladder Cancer Prognosis Programme

OBJECTIVE

Between 10 and 20% of bladder cancer patients who are diagnosed with nonmuscle-invasive bladder cancer will progress to muscle-invasive disease. Risk of progression depends on several factors at diagnosis including age, tumour stage, grade, size and number, and the presence or absence of carcinoma in situ. Fluid intake may be related to these factors.

METHODS

Data of 1123 participants from the West Midlands Bladder Cancer Prognosis Programme were used. Data collection was via a semistructured questionnaire, and case report forms were used to collect clinicopathological data. Fluid intake was measured for six main categories: alcoholic fluids, hot fluids, fruit fluids, milk, fizzy drinks, and water, and converted into quintile variables. Multilevel mixed-effects linear regression was performed for every beverage category per clinicopathological variable and corrected for age, gender, and smoking status.

RESULTS

Age at diagnosis was distributed differently amongst those in different total fluid intake quintiles (predicted means 71.5, 70.9, 71.5, 69.9, and 67.4, respectively) and showed a significant inverse linear trend in alcohol (P < 0.01), hot fluids (P < 0.01), and total fluids intake (P < 0.01), in nonmuscle-invasive bladder cancer patients.

CONCLUSION

Our results suggest an inverse association for alcohol intake and total fluid intake with age at diagnosis. These results should be confirmed by future studies, alongside a possible (biological) mechanism that could influence tumour growth, and the effect of micturition frequency.

The Epidemiology of Bladder Cancer

There are many risk factors for bladder cancer. During an initial assessment of a patient with bladder cancer, a careful discussion and history assessment is important. Particular focus should include social history with details regarding occupational background and discussion of any environmental exposure history.

Alcohol Drinking and Bladder Cancer Risk From a Pooled Analysis of Ten Cohort Studies in Japan

BACKGROUND

The association of alcohol drinking with bladder cancer risk remains unclear in East Asian populations. Aldehyde dehydrogenase 2 (ALDH2) enzyme oxidizes alcohol-metabolized carcinogenic acetaldehyde into acetate. It is well known that the inactive ALDH2 carriers, specific to East Asian populations, have an increased risk of several cancer types because of increased exposure to acetaldehyde after alcohol consumption. The aim of this study was to examine the association between alcohol drinking and bladder cancer risk using data from ten population-based prospective cohort studies in Japan, where approximately 40% of the population has inactive ALDH2 enzyme.

METHODS

We analyzed 340,497 Japanese participants with average follow-up of 13.4 years. The association between alcohol drinking and bladder cancer risk was evaluated using Cox regression models within each study, and random-effects models were used to estimate pooled hazard ratios (HRs) with corresponding 95% confidence intervals (CIs).

RESULTS

During 4,729,071 person-years, 936 men and 325 women were newly diagnosed with bladder cancer. Our results showed no evidence of significant association between alcohol drinking and bladder cancer risk even among men who consumed alcohol of ≥69 g/week, with HR of 1.02 (95% CI, 0.79-1.33). The null result was observed consistently among women.

CONCLUSIONS

Our findings do not support an association between alcohol drinking and bladder cancer risk in the Japanese, at least without consideration of the polymorphisms of alcohol-metabolizing enzymes.

Bladder Cancer in Iran: An Epidemiological Review

PURPOSE

Bladder cancer is the sixth most common cancer in Iran. Information about the epidemiological situation of the disease and its risk factors is necessary for conducting a planning program to reduce the disease. This study is conducted with the aim of evaluating the epidemiological features of bladder cancer in Iran.

METHODS

This is a systematic review of the published articles in both Persian and English in international and national journals during the years 2000-2019 with key words of Iran and bladder cancer. Articles were selected from the national information database (SID, Magiran) and international databases (PubMed, Scopus, and Web of Science). Articles related to the epidemiological aspects of the disease, including incidence, prevalence, mortality, and risk factors, were evaluated.

RESULTS

The incidence rate of bladder cancer was about 1.6-115; cumulative survival rate was 0.95, mortality rate was 0.5-0.84 and its prevalence in the Iranian population was between 4.10% and 12.8%. The risk of developing malignancy in major risk factor groups, including smoking and opium, was 6.2 (2.04-18.7), increases in protein and animal fat consumption were about 5- and 19-times higher than in the general population, respectively. In terms of occupational exposure, bus and heavy truck drivers were 11.3 (1.3-92.05) more at risk than others.

CONCLUSION

Regarding the increasing trend of this disease, changes in lifestyle to reduce risk factors can be effective in decreasing the incidence and mortality rate of this malignancy.

The interaction of gender and smoking on bladder cancer risks

PURPOSE OF REVIEW

Although smoking and gender are well-established bladder cancer (BCa) risk factors, a significant interaction with other risk factors could help in the identification of patterns for early detection and prevention strategies.

RECENT FINDINGS

Smoking appears to be more strongly associated with BCa risk in women than in men, which could be related to differences in metabolism, smoking behavior, exposure patterns, and DNA repair mechanisms. BMI is associated with a higher risk of BCa with negligible difference between genders. The risk for BCa is increased in postmenopausal women, specifically in women with earlier menopausal age (<45 years). Other potential risk factors such as alcohol, arsenic exposure, and particulate matter inhalation seem to affect the genders differently.Female smokers experience a higher risk of disease recurrence after bacillus Calmette-Guérin therapy than their male counterparts. Lastly, smoking appears to negatively affect the outcome of radiotherapy in women, but not that of men.

SUMMARY

Several lines of evidence point to an interaction between smoking and gender, whereas their impact on other potential risk factors remains to be elucidated. Identifying such differential effects could allow for gender-specific prevention, early detection, and treatment strategies.

Impact of alcohol consumption on the risk of developing bladder cancer: a systematic review and meta-analysis

BACKGROUND

Epidemiologic studies that investigated alcohol consumption in relation to the risk of bladder cancer (BCa) have demonstrated inconsistent results. We conducted a systematic review and meta-analysis of the literature to investigate the association of alcohol including different types of alcoholic beverages consumption with the risk of BCa.

MATERIALS AND METHODS

A systematic search of Web of Science, Medline/PubMed and Cochrane library was performed in May 2018. Studies were considered eligible if they assessed the risk of BCa due to alcohol consumption (moderate or heavy dose) and different types of alcoholic beverages (moderate or heavy dose) in multivariable analysis in the general population (all genders, males or females) or compared with a control group of individuals without BCa.

STUDY DESIGN

observational cohorts or case-control.

RESULTS

Sixteen studies were included in this meta-analysis. Moderate and heavy alcohol consumption did not increase the risk of BCa in the entire population. Sub-group and sensitivity analyses revealed that heavy alcohol consumption increased significantly the risk of BCa in the Japanese population, RR 1.31 (95% CI 1.08-1.58, P < 0.01) in the multivariable analysis, and in males RR of 1.50 (95% CI 1.18-1.92, P < 0.01), with no significant statistical heterogeneity. Moreover, heavy consumption of spirits drinks increased the risk of BCa in males, RR 1.42 (95% CI 1.15-1.75, P < 0.01).

CONCLUSION

In this meta-analysis, moderate and heavy alcohol consumption did not increase the risk of bladder cancer significantly. However, heavy consumption of alcohol might increase the risk of BCa in males and in some specific populations.

Mediterranean Diet and Bladder Cancer Risk in Italy

Previous studies have reported that Mediterranean diet is inversely related to the risk of several neoplasms; however, limited epidemiological data are available for bladder cancer. Thus, we examined the association between Mediterranean diet and this neoplasm in an Italian multicentric case-control study consisting of 690 bladder cancer cases and 665 controls. We assessed the adherence to the Mediterranean diet via a Mediterranean Diet Score (MDS), which represents the major characteristics of the Mediterranean diet and ranges from 0 to 9 (from minimal to maximal adherence, respectively). We derived odds ratios (ORs) of bladder cancer according to the MDS score from multiple logistic regression models, allowing for major confounding factors. The ORs of bladder cancer were 0.72 (95% confidence interval, CI, 0.54–0.98) for MDS of 4–5 and 0.66 (95% CI, 0.47–0.93) for MDS of 6–9 (p for trend = 0.02) compared to MDS = 0–3. Results were similar in strata of sex, age, and education, while the risk appeared somewhat lower in never-smokers and patients with pT1–pT4 bladder carcinomas. Among individual components of the MDS, we observed inverse associations for greater consumption of legumes, vegetables, and fish. In our study, which was carried out on an Italian population, the higher adherence to the Mediterranean diet was related to a lower risk of bladder cancer.

Alcohol consumption and risk of urothelial cell bladder cancer in the European prospective investigation into cancer and nutrition cohort

Findings on the association between alcohol consumption and bladder cancer are inconsistent. We investigated that association in the European Prospective Investigation into Cancer and Nutrition cohort. We included 476,160 individuals mostly aged 35-70 years, enrolled in ten countries and followed for 13.9 years on average. Hazard ratios (HR) for developing urothelial cell carcinoma (UCC; 1,802 incident cases) were calculated using Cox proportional hazards models. Alcohol consumption at baseline and over the life course was analyzed, as well as different types of beverages (beer, wine, spirits). Baseline alcohol intake was associated with a statistically nonsignificant increased risk of UCC (HR 1.03; 95% confidence interval (CI) 1.00-1.06 for each additional 12 g/day). HR in smokers was 1.04 (95% CI 1.01-1.07). Men reporting high baseline intakes of alcohol (>96 g/day) had an increased risk of UCC (HR 1.57; 95% CI 1.03-2.40) compared to those reporting moderate intakes (<6 g/day), but no dose-response relationship emerged. In men, an increased risk of aggressive forms of UCC was observed even at lower doses (>6 to 24 g/day). Average lifelong alcohol intake was not associated with the risk of UCC, however intakes of spirits > 24 g/day were associated with an increased risk of UCC in men (1.38; 95% CI 1.01-1.91) and smokers (1.39; 95% CI 1.01-1.92), compared to moderate intakes. We found no association between alcohol and UCC in women and never smokers. In conclusion, we observed some associations between alcohol and UCC in men and in smokers, possibly because of residual confounding by tobacco smoking.

STOP smoking and alcohol drinking before OPeration for bladder cancer (the STOP-OP study), perioperative smoking and alcohol cessation intervention in relation to radical cystectomy: study protocol for a randomised controlled trial

Background

To evaluate the effect of a smoking-, alcohol- or combined-cessation intervention starting shortly before surgery and lasting 6 weeks on overall complications after radical cystectomy. Secondary objectives are to examine the effect on types and grades of complications, smoking cessation and alcohol cessation, length of hospital stay, health-related quality of life and return to work or habitual level of activity up to 12 months postoperatively.

Methods/design

The study is a multi-institutional randomised clinical trial involving 110 patients with a risky alcohol intake and daily smoking who are scheduled for radical cystectomy. Patients will be randomised to the 6-week Gold Standard Programme (GSP) or treatment as usual (control). The GSP combines patient education and pharmacologic strategies. Smoking and alcohol intake is biochemically validated (blood, urine and breath tests) at the weekly meetings and at follow-up.

Discussion

Herein, we report the design of the STOP-OP study, objectives and accrual up-date. This study will provide new knowledge about how to prevent smoking and alcohol-related postoperative complications at the time of bladder cancer surgery. Till now 77 patients have been enrolled. Patient accrual is expected to be finalised before the end of 2017 and data will be published in 2018.

Trial registration

ClinicalTrials.gov, ID: NCT02188446. Registered on 28 May 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2065-6) contains supplementary material, which is available to authorized users.

Modifiable risk factors for the prevention of bladder cancer: a systematic review of meta-analyses

Each year, 430,000 people are diagnosed with bladder cancer. Due to the high recurrence rate of the disease, primary prevention is paramount. Therefore, we reviewed all meta-analyses on modifiable risk factors of primary bladder cancer. PubMed, Embase and Cochrane database were systematically searched for meta-analyses on modifiable risk factors published between 1995 and 2015. When appropriate, meta-analyses (MA) were combined in meta-meta-analysis (MMA). If not, the most comprehensive MA was selected based on the number of primary studies included. Probability of causation was calculated for individual factors and a subset of lifestyle factors combined. Of 1496 articles identified, 5 were combined in MMA and 21 were most comprehensive on a single risk factor. Statistically significant associations were found for current (RR 3.14) or former (RR 1.83) cigarette smoking, pipe (RR 1.9) or cigar (RR 2.3) smoking, antioxidant supplementation (RR 1.52), obesity (RR 1.10), higher physical activity levels (RR 0.86), higher body levels of selenium (RR 0.61) and vitamin D (RR 0.75), and higher intakes of: processed meat (RR 1.22), vitamin A (RR 0.82), vitamin E (RR 0.82), folate (RR 0.84), fruit (RR 0.77), vegetables (RR 0.83), citrus fruit (RR 0.85), and cruciferous vegetables (RR 0.84). Finally, three occupations with the highest risk were tobacco workers (RR 1.72), dye workers (RR 1.58), and chimney sweeps (RR 1.53). The probability of causation for individual factors ranged from 4 to 68 %. The combined probability of causation was 81.8 %. Modification of lifestyle and occupational exposures can considerably reduce the bladder cancer burden. While smoking remains one of the key risk factors, also several diet-related and occupational factors are very relevant.

Aldehyde dehydrogenase 2 (ALDH2) and alcohol dehydrogenase 1B (ADH1B) polymorphisms exacerbate bladder cancer risk associated with alcohol drinking: gene-environment interaction

Although a range of chemical exposures (cigarette smoking and occupational exposure) are recognized risk factors for the development of bladder cancer (BCa), many epidemiological studies have demonstrated that alcohol drinking is not associated with BCa risk. Aldehyde dehydrogenase 2 (ALDH2; rs671, Glu504Lys) and alcohol dehydrogenase 1B (ADH1B; rs1229984, His47Arg) polymorphisms impact the accumulation of acetaldehyde, resulting in an increased risk of various cancers. To date, however, no studies evaluating the association between BCa risk and alcohol drinking have considered these polymorphisms. Here, we conducted a matched case-control study to investigate whether ALDH2 and ADH1B polymorphisms influence BCa risk associated with alcohol drinking. Cases were 74 BCa patients and controls were 740 first-visit outpatients without cancer at Aichi Cancer Center Hospital between January 2001 and December 2005. Odds ratio (OR), 95% confidence interval (CI) and gene-environment interaction were assessed by conditional logistic regression analysis with adjustment for potential confounders. Results showed that ALDH2 Glu/Lys was associated with a significantly increased risk of BCa compared with Glu/Glu (OR 2.03, 95% CI 1.14-3.62, P = 0.017). In contrast, ALDH2 Glu/Lys showed no increase in risk among the stratum of never drinkers compared with Glu/Glu, indicating a gene-environment interaction. ADH1B His/Arg had an OR of 1.98 (1.20-3.24, P = 0.007) compared with His/His. ADH1B Arg+ showed a similar OR and 95% CI. Individuals with ALDH2 Glu/Lys and ADH1B Arg+ had the highest risk of BCa compared with ALDH2 Glu/Glu and ADH1B His/His [OR 4.00 (1.81-8.87), P = 0.001].

Association between alcohol consumption and the risk of ovarian cancer: a meta-analysis of prospective observational studies

Background

Alcohol consumption has been inconsistently associated with the risk of ovarian cancer. The purpose of this study was to summarize the data from prospective cohort studies on the relationship between alcohol consumption and ovarian cancer using a meta-analytic approach.

Methods

We performed electronic searches of PubMed, Embase, and the Cochrane Library in May 2014 to identify studies that examined the effects of alcohol consumption on the incidence of ovarian cancer. Only prospective cohort studies that reported effect estimates about the incidence of ovarian cancer with 95% confidence intervals (CIs) of alcohol intake were included.

Results

Collectively, we included 13 prospective studies that reported on data from 1,996,841 individuals and included 5,857 cases of ovarian cancer. Alcohol consumption had little to no effect on ovarian cancer incidence when compared to non-drinkers (risk ratio [RR], 1.03; 95% CI, 0.96–1.10; P = 0.473). Similarly, low (RR, 0.96; 95% CI, 0.93–1.00; P = 0.059), moderate (RR, 1.08; 95% CI, 0.92–1.27; P = 0.333), and heavy (RR, 0.99; 95% CI, 0.88–1.12; P = 0.904) alcohol consumption was not associated with the risk of ovarian cancer. Furthermore, subgroup analyses suggested that low alcohol intake was associated with a reduced risk of ovarian cancer whereas heavy alcohol intake was associated with an increased risk of ovarian cancer in multiple subpopulations.

Conclusions

Our study suggests that alcohol intake is not associated with an increased risk of ovarian cancer. Subgroup analyses indicated that alcohol consumption might be associated with the risk of ovarian cancer in specific population or in studies with specific characteristics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1355-8) contains supplementary material, which is available to authorized users.

Alcohol consumption and site-specific cancer risk: a comprehensive dose-response meta-analysis

BACKGROUND

Alcohol is a risk factor for cancer of the oral cavity, pharynx, oesophagus, colorectum, liver, larynx and female breast, whereas its impact on other cancers remains controversial.

METHODS

We investigated the effect of alcohol on 23 cancer types through a meta-analytic approach. We used dose-response meta-regression models and investigated potential sources of heterogeneity.

RESULTS

A total of 572 studies, including 486 538 cancer cases, were identified. Relative risks (RRs) for heavy drinkers compared with nondrinkers and occasional drinkers were 5.13 for oral and pharyngeal cancer, 4.95 for oesophageal squamous cell carcinoma, 1.44 for colorectal, 2.65 for laryngeal and 1.61 for breast cancer; for those neoplasms there was a clear dose-risk relationship. Heavy drinkers also had a significantly higher risk of cancer of the stomach (RR 1.21), liver (2.07), gallbladder (2.64), pancreas (1.19) and lung (1.15). There was indication of a positive association between alcohol consumption and risk of melanoma and prostate cancer. Alcohol consumption and risk of Hodgkin's and Non-Hodgkin's lymphomas were inversely associated.

CONCLUSIONS

Alcohol increases risk of cancer of oral cavity and pharynx, oesophagus, colorectum, liver, larynx and female breast. There is accumulating evidence that alcohol drinking is associated with some other cancers such as pancreas and prostate cancer and melanoma.

Alcohol consumption and hip fracture risk

SUMMARY

The present meta-analysis shows that a nonlinear association between alcohol consumption and the risk of hip fracture was observed. Light alcohol consumption was inversely significantly associated with hip fracture risk, whereas heavy alcohol consumption was associated with an elevated hip fracture risk.

INTRODUCTION

Previous studies examining the association between alcohol consumption and the risk of hip fracture have reported conflicting findings. Therefore, we conducted a meta-analysis of prospective cohort studies to assess the association between alcohol consumption and the risk of hip fracture.

METHODS

PubMed and EMBASE were searched for prospective cohort studies on the relationship between alcohol consumption and the risk of hip fractures. Relative risks (RR) with 95% confidence intervals (CI) were derived using random-effects models throughout the whole analysis.

RESULTS

Eighteen prospective cohort studies were included with 3,730,424 participants and 26,168 hip fracture cases. Compared with non-drinkers, the pooled RR of hip fractures for alcohol consumption was 1.03 (95% CI, 0.91-1.15), with high heterogeneity between studies (P<0.001, I2=72.6%). A nonlinear relationship between alcohol consumption and the risk of hip fracture was identified (P nonlinearity=0.003). Compared with non-drinkers, the pooled RRs of hip fractures were 0.88 (95% CI, 0.83-0.89) for light alcohol consumption (0.01-12.5 g/day), 1.00 (95% CI, 0.85-1.14) for moderate alcohol consumption (12.6-49.9 g/day), and 1.71 (95% CI, 1.41-2.01) for heavy alcohol consumption (≥50 g/day).

CONCLUSIONS

There was no evidence of publication bias. In conclusion, a nonlinear association between alcohol consumption and the risk of hip fracture was observed in this meta-analysis. Further, light alcohol consumption was inversely significantly associated with hip fracture risk, whereas heavy alcohol consumption was associated with an elevated hip fracture risk.

Environmental non-occupational risk factors associated with bladder cancer

CONTEXT

Bladder carcinoma (BC), due its high morbidity and relapsing course, generates significant economic and health care costs. Accordingly, review the environmental nonoccupational risk factors (RF), more or less evidence-based, in the etiology and pathogenesis of BC, because the involvement of urologists is essential for prevention.

ACQUISITION OF EVIDENCE

Review of the peer-reviewed literature (1987-2012) on nonoccupational environmental RF associated with BC retrieved from Medline, Embase and Science Citation Index. The search profiles have been "Risk factors/Epidemiology/Tobacco-smoking/Diet-nutrition-water-liquids/Radiation/Infectious/Farmacological drugs" and "Bladder cancer".

SYNTHESIS OF EVIDENCE

Smoking was associated with 50% of BC in both sexes. Smokers have a 2-5 times higher risk than nonsmokers, directly proportional to the amount and duration of addiction. Drinking water contaminated with arsenic and chromium chlorination byproducts increases the risk of BC. High consumption of red meat and saturated fat may increase the risk, while high intake of fruits and vegetables decreases it. Patients treated with cyclophosphamide, ifosfamide and ionizing radiation have an increased risk of BC. Frequent and prolonged use of hair dyes and Schistosoma haematobium infestation increases the risk of BC.

CONCLUSIONS

The reduction or the cessation of smoking decrease BC. The contaminant-free water consumption with the increase of vegetal foods favour BC prevention. Cancer survivors treated with cyclophosphamide, ifosfamide and radiation therapy should be monitored for early diagnosis of BC.

Bladder cancer: a simple model becomes complex

Bladder cancer is one of the most frequent malignancies in developed countries and it is also characterized by a high number of recurrences. Despite this, several authors in the past reported that only two altered molecular pathways may genetically explain all cases of bladder cancer: one involving the FGFR3 gene, and the other involving the TP53 gene. Mutations in any of these two genes are usually predictive of the malignancy final outcome. This cancer may also be further classified as low-grade tumors, which is always papillary and in most cases superficial, and high-grade tumors, not necessarily papillary and often invasive. This simple way of considering this pathology has strongly changed in the last few years, with the development of genome-wide studies on expression profiling and the discovery of small non-coding RNA affecting gene expression. An easy search in the OMIM (On-line Mendelian Inheritance in Man) database using "bladder cancer" as a query reveals that genes in some way connected to this pathology are approximately 150, and some authors report that altered gene expression (up- or down-regulation) in this disease may involve up to 500 coding sequences for low-grade tumors and up to 2300 for high-grade tumors. In many clinical cases, mutations inside the coding sequences of the above mentioned two genes were not found, but their expression changed; this indicates that also epigenetic modifications may play an important role in its development. Indeed, several reports were published about genome-wide methylation in these neoplastic tissues, and an increasing number of small non-coding RNA are either up- or down-regulated in bladder cancer, indicating that impaired gene expression may also pass through these metabolic pathways. Taken together, these data reveal that bladder cancer is far to be considered a simple model of malignancy. In the present review, we summarize recent progress in the genome-wide analysis of bladder cancer, and analyse non-genetic, genetic and epigenetic factors causing extensive gene mis-regulation in malignant cells.

Alcohol drinking and all cancer mortality: a meta-analysis

BACKGROUND

Epidemiological studies have suggested an inconsistent relationship between alcohol drinking and risk of all cancer mortality. As far as we know, no meta-analysis has been conducted to explore this issue.

PATIENTS AND METHODS

We carried out a PubMed search to find relevant articles published before April 2012 in English. Categorical and dose-response meta-analyses were conducted to identify the impact of alcohol drinking on all cancer mortality. Potential sources of heterogeneity were detected by meta-regression and stratification analyses. Sensitivity and cumulative meta-analyses were also carried out.

RESULTS

Eighteen independent cohort studies met the inclusion criteria. Compared with non/occasional drinkers, the pooled relative risks (RRs) were 0.91 [95% confidence interval (CI) 0.89-0.94] for light, 1.02 (95% CI 0.99-1.06) for moderate, and 1.31 (95% CI 1.23-1.39) for heavy drinkers. Former drinkers presented a higher risk (RR = 1.32, 95% CI 1.15-1.50) than current drinkers (RR = 1.06, 95% CI 0.98-1.16). There was a J-shaped relationship between all cancer mortality and alcohol consumption in males but not in females.

CONCLUSIONS

This meta-analysis confirms the health hazards of heavy drinking (≥50 g/day) and benefits of light drinking (≤12.5 g/day). Large-sample, well-designed, prospective epidemiological studies, especially on heavy drinking among women, should be developed in future.

Epidemiology and risk factors of urothelial bladder cancer

CONTEXT

Urothelial bladder cancer (UBC) is a disease of significant morbidity and mortality. It is important to understand the risk factors of this disease.

OBJECTIVE

To describe the incidence, prevalence, and mortality of UBC and to review and interpret the current evidence on and impact of the related risk factors.

EVIDENCE ACQUISITION

A literature search in English was performed using PubMed. Relevant papers on the epidemiology of UBC were selected.

EVIDENCE SYNTHESIS

UBC is the 7th most common cancer worldwide in men and the 17th most common cancer worldwide in women. Approximately 75% of newly diagnosed UBCs are noninvasive. Each year, approximately 110 500 men and 70 000 women are diagnosed with new cases and 38 200 patients in the European Union and 17 000 US patients die from UBC. Smoking is the most common risk factor and accounts for approximately half of all UBCs. Occupational exposure to aromatic amines and polycyclic aromatic hydrocarbons are other important risk factors. The impact of diet and environmental pollution is less evident. Increasing evidence suggests a significant influence of genetic predisposition on incidence.

CONCLUSIONS

UBC is a frequently occurring malignancy with a significant impact on public health and will remain so because of the high prevalence of smoking. The importance of primary prevention must be stressed, and smoking cessation programs need to be encouraged and supported.