Coffee and cancer: a prospective study of 43,000 Norwegian men and women

Exposure to polycyclic aromatic hydrocarbons (PAHs) and bladder cancer: evaluation from a gene-environment perspective in a hospital-based case-control study in the Canary Islands (Spain)

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been linked to bladder cancer.

OBJECTIVE

To evaluate the role of PAHs in bladder cancer, PAHs serum levels were measured in patients and controls from a case-control study.

METHODS

A total of 140 bladder cancer patients and 206 healthy controls were included in the study. Sixteen PAHs were analyzed from the serum of subjects by gas chromatography-mass spectrometry.

RESULTS

Serum PAHs did not appear to be related to bladder cancer risk, although the profile of contamination by PAHs was different between patients and controls: pyrene (Pyr) was solely detected in controls and chrysene (Chry) was exclusively detected in the cases. Phenanthrene (Phe) serum levels were inversely associated with bladder cancer (OR = 0·79, 95%CI = 0·64-0·99, P = 0·030), although this effect disappeared when the allelic distribution of glutathione-S-transferase polymorphisms of the population was introduced into the model (multinomial logistic regression test, P = 0·933). Smoking (OR = 3·62, 95%CI = 1·93-6·79, P<0·0001) and coffee consumption (OR = 1·73, 95%CI = 1·04-2·86, P = 0·033) were relevant risk factors for bladder cancer.

CONCLUSIONS

Specific PAH mixtures may play a relevant role in bladder cancer, although such effect seems to be highly modulated by polymorphisms in genes encoding xenobiotic-metabolizing enzymes.

Factors that affect risk for pancreatic disease in the general population: a systematic review and meta-analysis of prospective cohort studies

BACKGROUND & AIMS

Pancreatic diseases place significant burdens on health care systems worldwide. However, there is lack of agreement about which factors increase or reduce risk for pancreatic disease. We reviewed high-quality studies of factors that affect risk for pancreatic diseases in the general population.

METHODS

We searched 3 databases (Medline, Embase, and Scopus) for prospective cohort studies of modifiable risk and/or protective factors for acute pancreatitis, chronic pancreatitis, and pancreatic cancer in adult populations. Factors that were investigated in 2 or more studies were assessed by meta-analysis if the required data were available. Subgroup analyses were performed when appropriate. Outcome measures were relative risk (RR) and 95% confidence interval (CI).

RESULTS

Our analysis included 51 population-based studies with more than 3 million individuals and nearly 11,000 patients with pancreatic diseases. A total of 31 different factors were investigated. Current tobacco use was the single most important risk factor for pancreatic diseases (RR, 1.87; 95% CI, 1.54-2.27), followed by obesity (RR, 1.48; 95% CI, 1.15-1.92) and heavy use of alcohol (RR, 1.37; 95% CI, 1.19-1.58). Tobacco and heavy use of alcohol had bigger effects on risk of acute pancreatitis and chronic pancreatitis than pancreatic cancer. Vegetable consumption (RR, 0.71; 95% CI, 0.57-0.88) and fruit consumption (RR, 0.73; 95% CI, 0.60-0.90) provided the greatest degree of protection against pancreatic diseases on the basis of meta-analyses. Vegetable consumption had stronger association with protection against acute pancreatitis and fruit consumption with protection against pancreatic cancer.

CONCLUSIONS

On the basis of systematic review and meta-analysis, current tobacco use, obesity, and heavy use of alcohol are associated with significant increases in risk for pancreatic diseases. Vegetables and fruit consumption are associated with reduced risk for pancreatic diseases. Prevention strategies for acute pancreatitis, chronic pancreatitis, and pancreatic cancer should consider these factors.

Coffee consumption and risk of gastric cancer: a large updated meta-analysis of prospective studies

The potential role of coffee consumption in the development of various types of cancer has been extensively investigated in epidemiologic studies. How coffee consumption may modulate risk of gastric cancer, however, remains a subject open for investigation. To better quantify this relation, we quantitatively summarized evidence from prospective studies. Eligible studies were identified on PubMed databases. The summary risk estimates were obtained using the random-effects model. Subgroup, sensitivity and dose-response analyses were conducted. The present meta-analysis included 12 prospective cohort studies. A pooled analysis of these studies suggested that coffee consumption (highest vs. lowest consumption) was not associated with risk of gastric cancer (RR = 1.12, 95% CI = 0.93–1.36). In the subgroup analysis, significant increased risk was detected in the U.S. studies (RR = 1.36, 95% CI = 1.06–1.74) and in the studies with <10 years of follow-up (RR = 1.24, 95% CI = 1.00–1.54), and the greatest increase in risk was observed in those studies without adjustment for smoking (RR = 1.48, 95% CI = 1.13–1.93). There was some evidence of publication bias (P for Egger’s test = 0.03). Cumulative evidence from prospective studies suggests that coffee consumption is not associated with risk of gastric cancer. The observed positive results may be confounded by smoking and need further investigation.

Endometrial cancer in relation to coffee, tea, and caffeine consumption: a prospective cohort study among middle-aged women in Sweden

This study aimed to add to prospective data on the possible inverse association between coffee consumption and endometrial cancer risk, already supported by several case-control studies. Coffee and tea consumption and possible confounding factors were assessed among 42,270 women aged 30-49 years at enrollment in 1991-1992 in the Swedish Women's Lifestyle and Health cohort study, with complete follow-up through 2009. We calculated caffeine intake per day; Cox proportional hazard models were used to estimate multivariable relative risks (mRR) for endometrial cancer with 95% confidence intervals (CIs). One hundred forty-four endometrial cancers were diagnosed during follow-up. Women with and without endometrial cancer had a similar mean daily coffee consumption (549 vs. 547 g), tea consumption (104 vs. 115 g), and caffeine intake (405 vs. 406 mg). Compared to those consuming <2 cups of coffee per day, women consuming >3 cups had a mRR of 1.56 (95% CI: 0.94-2.59; P for trend = 0.17). Compared with the lowest tertile of caffeine intake, the highest tertile had a mRR of 1.32 (95% CI: 0.87-1.99; P for trend = 0.27). Our study provides no convincing evidence of an association between coffee consumption, tea consumption, or caffeine intake and endometrial cancer risk among middle-aged women.

Coffee consumption and risk of colorectal cancer: the Japan Collaborative Cohort Study

BACKGROUND

Epidemiologic studies have reported coffee consumption to be associated with various health conditions. The purpose of this study was to examine the relationship of coffee consumption with colorectal cancer incidence in a large-scale prospective cohort study in Japan.

METHODS

We used data from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study). Here, we analyzed a total of 58 221 persons (23 607 men, 34 614 women) followed from 1988 to the end of 2009. During 738 669 person-years of follow-up for the analysis of colorectal cancer risk with coffee consumption at baseline, we identified 687 cases of colon cancer (355 males and 332 females) and 314 cases of rectal cancer (202 males and 112 females). We used the Cox proportional-hazard regression model to estimate hazard ratio (HR).

RESULTS

Compared to those who consumed less than 1 cup of coffee per day, men who consumed 2-3 cups of coffee per day had an HR of 1.26 (95% confidence interval [CI] 0.93-1.70), and men who consumed more than 4 cups of coffee per day had an HR of 1.79 (95% CI 1.01-3.18). A statistically significant increase in the risk of colon cancer was associated with increasing coffee consumption among men (P for trend = 0.03). On the other hand, coffee consumption in women was not associated with incident risk of colon cancer. Coffee consumption was also not associated with rectal cancer incidence in men or women.

CONCLUSIONS

This large-scale population-based cohort study showed that coffee consumption increases the risk of colon cancer among Japanese men.

Coffee consumption and urologic cancer risk: a meta-analysis of cohort studies

OBJECTIVES

Controversial results were reported among several epidemiologic studies on the relationship between coffee consumption and urologic cancer risk. We, therefore, conducted this meta-analysis to clarify these associations.

METHODS

Electronic databases including Pubmed, Embase and Cochrane library were searched between January 1966 and August 2013 for eligible studies. Pooled relative risk (RR) and its 95 % confidence interval (CI) were calculated. All P values are two tailed.

RESULTS

Thirteen cohorts were eligible for inclusion. As to prostate cancer (PCa), significant reverse association was found among highest versus none/lowest analysis with acceptable heterogeneity (RR 0.86, 95 % CI 0.79-0.95; I(2) 25 %, P value for heterogeneity: 0.221). A pooled RR which assessed advanced PCa was 0.73 (with 95 % CI 0.50-1.07), and a slight stronger reverse association was found in fatal PCa. However, a slight insignificant reverse association, basing on 8 studies with 9 outcomes, was found in dose-response analysis (RR 0.98, 95 % CI 0.93-1.03). For kidney and bladder cancer, insignificant associations were found in both highest versus none/lowest analyses and dose-response analyses.

CONCLUSIONS

Our findings suggest that coffee consumption may reduce the risk of PCa. No associations were found with both bladder and kidney cancer. Further well-designed large-scaled cohort studies are warranted to provide more definitive conclusions.

Coffee and green tea consumption is associated with upper aerodigestive tract cancer in Japan

The impact of coffee and green tea consumption on upper aerodigestive tract (UADT) cancer risk has not been established. Evaluation of the possible anticarcinogenic properties of their ingredients is confounded by the potential increase in risk owing to the high temperatures at which these beverages are generally consumed. We conducted a case-control study to evaluate the association between coffee and tea consumption and the risk of UADT cancer. The study enrolled 961 patients with UADT cancer and 2,883 noncancer outpatients who visited Aichi Cancer Center between 2001 and 2005. Information on coffee and green tea consumption and other lifestyle factors was collected via a self-administered questionnaire. Consumption of three or more cups of coffee per day had a significant inverse association with UADT cancer [odds ratio (OR) 0.73, 95% confidence interval (CI) 0.55-0.96]. In contrast, consumption of three or more cups of green tea per day had a significant positive association with UADT cancer (OR 1.39, 95% CI 1.13-1.70). These associations were evident for head and neck cancer but not for esophageal cancer. The association of coffee consumption with head and neck cancer was observed only among never smokers and alcohol drinkers. Similarly, the association of green tea consumption was observed among never smokers and never alcohol drinkers. No change in these associations was seen on stratification by each confounding factors. These findings suggest that consumption of coffee might be associated with a decreased risk of UADT cancer, whereas that of green tea might be associated with an increased risk.

Coffee consumption and risk of prostate cancer: a meta-analysis of prospective cohort studies

Observational studies and animal evidence suggest an association between coffee consumption and the risk of prostate cancer. However, the results are inconsistent. We evaluated the association by conducting a meta-analysis of prospective cohort studies. PubMed and Embase were searched through June 2013 to identify studies that met predetermined inclusion criterion. A random-effects model was used to calculate the pooled risk estimates. Ten prospective cohort studies involving 8973 patients with prostate cancer and 206 096 participants were included in this systematic review. Compared with individuals who seldom or never drink coffee, the pooled relative risk of prostate cancer was 0.88 (95% confidence interval: 0.82-0.95) for regular coffee drinkers. Exclusion of any single study did not materially alter the combined risk estimate. Visual inspection of a funnel plot and Begg's and Egger's tests did not indicate evidence of publication bias. In summary, integrated evidence from prospective cohort studies supports the hypothesis that coffee consumption may decrease the risk of prostate cancer.

Coffee consumption and risk of prostate cancer: an up-to-date meta-analysis

BACKGROUND/OBJECTIVES

Epidemiologic findings concerning the association between coffee consumption and prostate cancer risk yielded mixed results. We aimed to investigate the association by performing a meta-analysis of all available studies.

SUBJECTS/METHODS

We searched PubMed, Web of Science and EMBASE for studies published up to July 2013. We calculated the summary relative risk (RR) and 95% confidence intervals (CIs) for ever, moderate and highest consumption of coffee vs non/lowest consumption. The dose-response relationship was assessed by restricted cubic spline model and multivariate random-effect meta-regression.

RESULTS

A total of 12 case-control studies and 12 cohort studies with 42,179 cases were selected for final meta-analysis. No significant associations were found among overall analysis. A borderline positive association was found for highest drinkers in five small hospital-based case-control (HCC) studies involving 2278 cases. However, compared with non/lowest drinkers, the summary RRs were 0.92 (95% CI=0.85-0.99) for ever drinkers, 0.92 (95% CI=0.85-1.00) for moderate drinkers and 0.83 (95% CI=0.72-0.96) for highest drinkers from 12 cohort studies, comprising a total of 34,424 cases. An increase in coffee intake of two cups/day was associated with a 7% decreased risk of prostate cancer according to cohort studies. A significant inverse relationship was also found for fatal prostate cancers and high-grade prostate cancers.

CONCLUSIONS

Case-control studies especially HCC ones might be prone to selection bias and recall bias that might have contributed to the conflicting results. Therefore, the present meta-analysis suggests a borderline significant inverse association between coffee consumption and prostate cancer risk based on cohort studies.

Ways to enhance lymphocyte trafficking into tumors and fitness of tumor infiltrating lymphocytes

The tumor is a hostile microenvironment for T lymphocytes. Indeed, irregular blood flow, and endothelial cell (EC) anergy that characterize most solid tumors hamper leukocyte adhesion, extravasation, and infiltration. In addition, hypoxia and reprograming of energy metabolism within cancer cells transform the tumor mass in a harsh environment that limits survival and effector functions of T cells, regardless of being induced in vivo by vaccination or adoptively transferred. In this review, we will summarize on recent advances in our understanding of the characteristics of tumor-associated neo-angiogenic vessels as well as of the tumor metabolism that may impact on T cell trafficking and fitness of tumor infiltrating lymphocytes. In particular, we will focus on how advances in knowledge of the characteristics of tumor ECs have enabled identifying strategies to normalize the tumor-vasculature and/or overcome EC anergy, thus increasing leukocyte-vessel wall interactions and lymphocyte infiltration in tumors. We will also focus on drugs acting on cells and their released molecules to transiently render the tumor microenvironment more suitable for tumor infiltrating T lymphocytes, thus increasing the therapeutic effectiveness of both active and adoptive immunotherapies.

Coffee consumption and risk of breast cancer: an up-to-date meta-analysis

Objectives

This updated meta-analysis was conducted to assess the association between coffee consumption and breast cancer risk.

Methods

We conducted a systematic search updated July 2012 to identify observational studies providing quantitative estimates for breast cancer risk in relation to coffee consumption. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and generalized least square trend estimation was used to assess dose–response relationships.

Results

A total of 26 studies (16 cohort and 10 case–control studies) on coffee intake with 49497 breast cancer cases were included in the meta-analysis. The pooled RR showed a borderline significant influence of highest coffee consumption (RR = 0.96; 95% CI 0.93–1.00), low-to moderate coffee consumption (RR = 0.99; 95% CI 0.95–1.04), or an increment of 2 cups/day of coffee consumption (RR = 0.98; 95% CI 0.97–1.00) on the risk of breast cancer. In stratified analysis, a significant inverse association was observed in ER-negative subgroup. However, no significant association was noted in the others.

Conclusions

Our findings suggest that increased coffee intake is not associated with a significantly reduced risk of breast cancer, but we observe an inverse association in ER-negative subgroup analysis. More large studies are needed to determine subgroups to obtain more valuable data on coffee drinking and breast cancer risk.

Increased caffeine intake is associated with reduced risk of basal cell carcinoma of the skin

Studies in animals suggest that caffeine administration helps prevent squamous cell skin cancer development, but there have been limited epidemiologic studies on the association between caffeine consumption and skin cancer risk. Using data from the Nurses' Health Study and the Health Professionals Follow-up Study, we prospectively examined risks of basal cell carcinoma (BCC, 22,786 cases), squamous cell carcinoma (SCC, 1,953 cases), and melanoma (741 cases) in relation to caffeine intake. Cox proportional hazard models were used to calculate relative risks (RR) and 95% confidence intervals (CI). The amount of caffeine intake from all dietary sources was inversely associated with BCC risk. Compared with the lowest quintile, the highest quintile had the lowest risk (RR, 0.82 in women; 95% CI:,0.77-0.86 and RR, 0.87 in men; 95% CI, 0.81-0.94; Ptrend<0.0001 in both). A significant inverse association was also found between caffeinated coffee consumption and BCC risk. Compared with individuals who consumed caffeinated coffee less than 1 cup per month, women who consumed more than 3 cups/d had the lowest risk (RR, 0.79; 95% CI, 0.74-0.85; Ptrend<0.0001) and the RR for men was 0.90 (95% CI, 0.80-1.01; Ptrend=0.003). Caffeine from other dietary sources (tea, cola, and chocolate) was also inversely associated with BCC risk. Decaffeinated coffee consumption was not associated with a similar decrease in BCC risk. In contrast, caffeine intake was not found to be inversely associated with risks of SCC or melanoma. Our findings argue that caffeine intake in men and women is inversely associated with risk of BCC.

Coffee consumption and risk of gastric and pancreatic cancer--a prospective cohort study

Only few prospective studies have examined the association between coffee consumption and risk of gastric and pancreatic cancer. This study is designed to evaluate this relationship among Finns, whose coffee consumption is the highest in the world. A total of 60,041 Finnish men and women who were 26-74 years of age and without history of any cancer at baseline were included in the present analyses. Coffee consumption and other study parameters were determined at baseline using standardized measurements. Participants were prospectively followed up for onset of gastric and/or pancreatic cancer, emigration, death or until June 30, 2006. During a mean follow-up period of 18 years, 299 cases of gastric cancer and 235 cases of pancreatic cancer were found. There was a nonsignificant inverse association between coffee consumption and risk of gastric cancer among men but not in the women. The multivariate-adjusted hazard ratio of stomach and pancreatic cancer incidence for ≥ 10 cups of coffee per day compared with nondrinkers were 0.75 (95% CI, 0.40-1.41) (P for trend = 0.19) and 0.82 (95% CI, 0.38-1.76) (P for trend = 0.95) for the combined population of men and women, respectively. We did not find a significant association between coffee consumption and the risk of gastric and/or pancreatic cancers.

Coffee consumption and risk of colorectal cancer: a meta-analysis of observational studies

Objective

Separate meta-analyses based on case–control and cohort studies have reported different results on the relationship between coffee consumption and colorectal cancer risk. To clarify the effect of coffee intake on colorectal cancer risk, we performed a meta-analysis based on both case–control and cohort studies.

Design

Review study.

Setting

We identified case–control and cohort studies related to coffee consumption and colorectal cancer risk listed on MEDLINE, the Cochrane Controlled Trials Register, EMBASE, Science Citation Index and PubMed (until May 2011).

Subjects

Research literature on the relationship between coffee consumption and colorectal cancer risk.

Results

Twenty-five case–control (15 522 cases) and sixteen cohort studies (10 443 cases) were included in the meta-analysis. Comparing the highest v. the lowest/non category of coffee consumption, the combined results from case–control studies showed a significant relationship with colorectal cancer (OR = 0·85, 95 % CI 0·75, 0·97) and colon cancer (OR = 0·79, 95 % CI 0·67, 0·95), but not rectal cancer (OR = 0·95, 95 % CI 0·79, 1·15). For cohort studies, there was a slight suggestion of an inverse association with colorectal cancer (relative ratio = 0·94; 95 % CI 0·88, 1·01) and colon cancer (OR = 0·93, 95 % CI 0·86, 1·01), rather than rectal cancer (OR = 0·98, 95 % CI 0·88, 1·09). In subgroup analyses using case–control studies, significant inverse associations were found in females for colorectal cancer and in Europe for colorectal and colon cancer, while the subgroup analyses of cohort studies found that coffee drinks substantially decreased risk of colon cancer only in Asian women.

Conclusions

Results from case–control studies suggest coffee consumption can significantly decrease the risks of colorectal cancer and colon cancer, especially in Europe and for females.

Coffee and tea consumption and the risk of ovarian cancer: a prospective cohort study and updated meta-analysis

BACKGROUND

In 2007 the World Cancer Research Fund Report concluded that there was limited and inconsistent evidence for an effect of coffee and tea consumption on the risk of epithelial ovarian cancer (EOC).

OBJECTIVE

In the European Prospective Investigation into Cancer and Nutrition (EPIC), we aimed to investigate whether coffee intakes, tea intakes, or both are associated with the risk of EOC.

DESIGN

All women participating in the EPIC (n = 330,849) were included in this study. Data on coffee and tea consumption were collected through validated food-frequency questionnaires at baseline. HRs and 95% CIs were estimated by using Cox proportional hazards models. Furthermore, we performed an updated meta-analysis of all previous prospective studies until April 2011 by comparing the highest and lowest coffee- and tea-consumption categories as well as by using dose-response random-effects meta-regression analyses.

RESULTS

During a median follow-up of 11.7 y, 1244 women developed EOC. No association was observed between the risk of EOC and coffee consumption [HR: 1.05 (95% CI: 0.75, 1.46) for the top quintile compared with no intake] or tea consumption [HR: 1.07 (95% CI: 0.78, 1.45) for the top quintile compared with no intake]. This lack of association between coffee and tea intake and EOC risk was confirmed by the results of our meta-analysis.

CONCLUSION

Epidemiologic studies do not provide sufficient evidence to support an association between coffee and tea consumption and risk of ovarian cancer.

Coffee, tea, and sugar-sweetened carbonated soft drink intake and pancreatic cancer risk: a pooled analysis of 14 cohort studies

BACKGROUND

Coffee has been hypothesized to have pro- and anticarcinogenic properties, whereas tea may contain anticarcinogenic compounds. Studies assessing coffee intake and pancreatic cancer risk have yielded mixed results, whereas findings for tea intake have mostly been null. Sugar-sweetened carbonated soft drink (SSB) intake has been associated with higher circulating levels of insulin, which may promote carcinogenesis. Few prospective studies have examined SSB intake and pancreatic cancer risk; results have been heterogeneous.

METHODS

In this pooled analysis from 14 prospective cohort studies, 2,185 incident pancreatic cancer cases were identified among 853,894 individuals during follow-up. Multivariate (MV) study-specific relative risks (RR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards models and then pooled using a random-effects model.

RESULTS

No statistically significant associations were observed between pancreatic cancer risk and intake of coffee (MVRR = 1.10; 95% CI, 0.81-1.48 comparing ≥900 to <0 g/d; 237g ≈ 8oz), tea (MVRR = 0.96; 95% CI, 0.78-1.16 comparing ≥400 to 0 g/d; 237g ≈ 8oz), or SSB (MVRR = 1.19; 95% CI, 0.98-1.46 comparing ≥250 to 0 g/d; 355g ≈ 12oz; P value, test for between-studies heterogeneity > 0.05). These associations were consistent across levels of sex, smoking status, and body mass index. When modeled as a continuous variable, a positive association was evident for SSB (MVRR = 1.06; 95% CI, 1.02-1.12).

CONCLUSION AND IMPACT

Overall, no associations were observed for intakes of coffee or tea during adulthood and pancreatic cancer risk. Although we were only able to examine modest intake of SSB, there was a suggestive, modest positive association for risk of pancreatic cancer for intakes of SSB.

A prospective cohort study of coffee consumption and risk of endometrial cancer over a 26-year follow-up

BACKGROUND

Coffee has been reported to lower levels of estrogen and insulin, two hormones implicated in endometrial carcinogenesis, but prospective data on the relation between coffee consumption and risk of endometrial cancer are limited.

METHODS

We prospectively assessed coffee consumption in relation to endometrial cancer risk in the Nurses' Health Study (NHS) with 67,470 female participants aged 34 to 59 in 1980. Cumulative average coffee intake was calculated with all available questionnaires to assess long-term effects. Cox regression models were used to calculate incidence rate ratios (RR), controlling for other risk factors.

RESULTS

Fewer than 4 cups of coffee per day were not associated with endometrial cancer risk. However, women who consumed 4 or more cups of coffee had 25% lower risk of endometrial cancer than those who consumed less than 1 cup per day (multivariable RR = 0.75; 95% CI = 0.57-0.97; P(trend) = 0.02). We found the similar association with caffeinated coffee consumption (RR for ≥4 vs. <1 cup/d = 0.70; 95% CI = 0.51-0.95). For decaffeinated coffee consumption, a suggestive inverse association was found among women who consumed 2 or more cups per day versus <1 cup/mo. Tea consumption was not associated with endometrial cancer risk.

CONCLUSIONS

These prospective data suggest that four or more cups of coffee per day are associated with a lower risk of endometrial cancer.

IMPACT

Drinking of coffee, given its widespread consumption, might be an additional strategy to reduce endometrial cancer risk. However, addition of substantial sugar and cream to coffee could offset any potential benefits.

Caffeinated coffee, decaffeinated coffee and endometrial cancer risk: a prospective cohort study among US postmenopausal women

There is plausible biological evidence as well as epidemiologic evidence to suggest coffee consumption may lower endometrial cancer risk. We evaluated the associations between self-reported total coffee, caffeinated coffee and decaffeinated coffee, and endometrial cancer risk using the Women's Health Initiative Observational Study Research Materials obtained from the National Heart, Lung, and Blood Institute Biological Specimen and Data Repository Coordinating Center. Our primary analyses included 45,696 women and 427 incident endometrial cancer cases, diagnosed over a total of 342,927 person-years of follow-up. We used Cox-proportional hazard models to evaluate coffee consumption and endometrial cancer risk. Overall, we did not find an association between coffee consumption and endometrial cancer risk. Compared to non-daily drinkers (none or <1 cup/day), the multivariable adjusted hazard ratios for women who drank ≥4 cups/day were 0.86 (95% confidence interval (CI) 0.63, 1.18) for total coffee, 0.89 (95% CI 0.63, 1.27) for caffeinated coffee, and 0.51 (95% CI 0.25, 1.03) for decaf coffee. In subgroup analyses by body mass index (BMI) there were no associations among normal-weight and overweight women for total coffee and caffeinated coffee. However among obese women, compared to the referent group (none or <1 cup/day), the hazard ratios for women who drank ≥2 cups/day were: 0.72 (95% CI 0.50, 1.04) for total coffee and 0.66 (95% CI 0.45, 0.97) for caffeinated coffee. Hazard ratios for women who drank ≥2 cups/day for decaffeinated coffee drinkers were 0.67 (0.43-1.06), 0.93 (0.55-1.58) and 0.80 (0.49-1.30) for normal, overweight and obese women, respectively. Our study suggests that caffeinated coffee consumption may be associated with lower endometrial cancer risk among obese postmenopausal women, but the association with decaffeinated coffee remains unclear.

Coffee intake and oral-oesophageal cancer: follow-up of 389,624 Norwegian men and women 40-45 years

Background:

The evidence on the relationship between coffee intake and cancer of the oral cavity and oesophagus is conflicting and few follow-up studies have been done.

Methods:

A total of 389 624 men and women 40–45 years who participated in a national survey programme were followed with respect to cancer for an average of 14.4 years by linkage to the Cancer Registry of Norway. Coffee consumption at baseline was reported as a categorical variable (0 or <1 cup, 1–4, 5–8, 9+ cups per day).

Results

Altogether 450 squamous oral or oesophageal cancers were registered during follow-up. The adjusted hazard ratios with 1–4 cups per day as reference were 1.01 (95% confidence interval: 0.70, 1.47), 1.16 (0.93, 1.45) and 0.96 (0.71, 1.14) for 0 or <1 cup, 5–8 and 9+ cups per day, respectively. Stratification by sex, type of coffee, smoking status and dividing the end point into oral and oesophageal cancers gave heterogeneous and non-significant estimates.

Conclusion:

This study does not support an inverse relationship between coffee intake and incidence of cancer in the mouth or oesophagus, but cannot exclude a weak inverse relationship.

Coffee consumption and risk of cancers: a meta-analysis of cohort studies

Background

Coffee consumption has been shown to be associated with cancer of various sites in epidemiological studies. However, there is no comprehensive overview of the substantial body of epidemiologic evidence.

Methods

We searched MEDLINE, EMBASE, Science Citation Index Expanded and bibliographies of retrieved articles. Prospective cohort studies were included if they reported relative risks (RRs) and corresponding 95% confidence intervals (CIs) of various cancers with respect to frequency of coffee intake. We did random-effects meta-analyses and meta-regressions of study-specific incremental estimates to determine the risk of cancer associated with 1 cup/day increment of coffee consumption.

Results

59 studies, consisting of 40 independent cohorts, met the inclusion criteria. Compared with individuals who did not or seldom drink coffee per day, the pooled RR of cancer was 0.87 (95% CI, 0.82-0.92) for regular coffee drinkers, 0.89 (0.84-0.93) for low to moderate coffee drinkers, and 0.82 (0.74-0.89) for high drinkers. Overall, an increase in consumption of 1 cup of coffee per day was associated with a 3% reduced risk of cancers (RR, 0.97; 95% CI, 0.96-0.98). In subgroup analyses, we noted that, coffee drinking was associated with a reduced risk of bladder, breast, buccal and pharyngeal, colorectal, endometrial, esophageal, hepatocellular, leukemic, pancreatic, and prostate cancers.

Conclusions

Findings from this meta-analysis suggest that coffee consumption may reduce the total cancer incidence and it also has an inverse association with some type of cancers.

Coffee consumption and risk of cancers: a meta-analysis of cohort studies

BACKGROUND

Coffee consumption has been shown to be associated with cancer of various sites in epidemiological studies. However, there is no comprehensive overview of the substantial body of epidemiologic evidence.

METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded and bibliographies of retrieved articles. Prospective cohort studies were included if they reported relative risks (RRs) and corresponding 95% confidence intervals (CIs) of various cancers with respect to frequency of coffee intake. We did random-effects meta-analyses and meta-regressions of study-specific incremental estimates to determine the risk of cancer associated with 1 cup/day increment of coffee consumption.

RESULTS

59 studies, consisting of 40 independent cohorts, met the inclusion criteria. Compared with individuals who did not or seldom drink coffee per day, the pooled RR of cancer was 0.87 (95% CI, 0.82-0.92) for regular coffee drinkers, 0.89 (0.84-0.93) for low to moderate coffee drinkers, and 0.82 (0.74-0.89) for high drinkers. Overall, an increase in consumption of 1 cup of coffee per day was associated with a 3% reduced risk of cancers (RR, 0.97; 95% CI, 0.96-0.98). In subgroup analyses, we noted that, coffee drinking was associated with a reduced risk of bladder, breast, buccal and pharyngeal, colorectal, endometrial, esophageal, hepatocellular, leukemic, pancreatic, and prostate cancers.

CONCLUSIONS

Findings from this meta-analysis suggest that coffee consumption may reduce the total cancer incidence and it also has an inverse association with some type of cancers.

Fluid intake and incidence of renal cell carcinoma in UK women

Background:

It has been suggested that the apparent protective effect of alcohol intake on renal cell carcinoma may be due to the diluting effect of carcinogens by a high total fluid intake. We assessed the association between intakes of total fluids and of specific beverages on the risk of renal cell carcinoma in a large prospective cohort of UK women.

Methods:

Information on beverage consumption was obtained from a questionnaire sent ∼3 years after recruitment into the Million Women Study. Cox proportional hazards models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for renal cell carcinoma associated with beverage consumption adjusted for age, region of residence, socioeconomic status, smoking, and body mass index.

Results:

After an average of 5.2 years of follow-up, 588 cases of renal cell carcinoma were identified among 779 369 women. While alcohol intake was associated with a reduced risk of renal cell carcinoma (RR for ⩾2 vs <1 drink per day: 0.76; 95% CI: 0.61–0.96; P for trend=0.02), there was no association with total fluid intake (RR for ⩾12 vs <7 drinks per day: 1.15; 95% CI: 0.91–1.45; P for trend=0.3) or with intakes of specific beverages.

Conclusions:

The apparent protective effect of alcohol on the risk of renal cell carcinoma is unlikely to be related to a high fluid intake.

Coffee drinking and pancreatic cancer risk: A meta-analysis of cohort studies

AIM: To quantitatively assess the relationship between coffee consumption and incidence of pancreatic cancer in a meta-analysis of cohort studies.

METHODS: We searched MEDLINE, EMBASE, Science Citation Index Expanded and bibliographies of retrieved articles. Studies were included if they reported relative risks (RRs) and corresponding 95% CIs of pancreatic cancer with respect to frequency of coffee intake. We performed random-effects meta-analyses and meta-regressions of study-specific incremental estimates to determine the risk of pancreatic cancer associated with a 1 cup/d increment in coffee consumption.

RESULTS: Fourteen studies met the inclusion criteria, which included 671 080 individuals (1496 cancer events) with an average follow-up of 14.9 years. Compared with individuals who did not drink or seldom drank coffee per day, the pooled RR of pancreatic cancer was 0.82 (95% CI: 0.69-0.95) for regular coffee drinkers, 0.86 (0.76-0.96) for low to moderate coffee drinkers, and 0.68 (0.51-0.84) for high drinkers. In subgroup analyses, we noted that, coffee drinking was associated with a reduced risk of pancreatic cancer in men, while this association was not seen in women. These associations were also similar in studies from North America, Europe, and the Asia-Pacific region.

CONCLUSION: Findings from this meta-analysis suggest that there is an inverse relationship between coffee drinking and risk of pancreatic cancer.

Chlorogenic acid differentially alters hepatic and small intestinal thiol redox status without protecting against azoxymethane-induced colon carcinogenesis in mice

Colorectal cancer (CRC) is a leading cause of cancer-related deaths in the United States. Epidemiological data have suggested that coffee consumption is inversely related to CRC risk, which may be attributed to chlorogenic acid (CGA), an ester of caffeic acid (CA) and quinic acid. This study was conducted to determine whether chronic dietary CGA supplementation would attenuate tumorigenesis and oxidative stress in a mouse model of azoxymethane (AOM)-induced colon cancer. Mice (4-wk old; n = 15/group) were fed CGA (0%, 0.01%, or 0.1%) for 20 wk and received 6 weekly intraperitoneal AOM injections (10 mg/kg). CGA and CA dose-dependently accumulated in the small intestinal mucosa. AOM induced (P < 0.05) colonic aberrant crypt foci (14.2 +/- 1.9/field) and tumors (14.6 +/- 1.1/colon), which were correlated (r = .677; P < 0.05), and CGA at either dose did not reduce tumorigenesis. Hepatic GSH/GSSG and Cys/CySS ratios were unaffected by AOM, but CGA at 0.1% increased these ratios by decreasing GSSG and CySS. CGA did not affect the ratios of small intestinal GSH/GSSG or Cys/CySS, which were decreased in response to AOM treatment. Collectively, these data indicated that CGA did not protect against AOM-induced tumorigenesis but affected hepatic thiol redox status in this colon cancer model.

Coffee and tea intake and risk of head and neck cancer: pooled analysis in the international head and neck cancer epidemiology consortium

BACKGROUND

Only a few studies have explored the relation between coffee and tea intake and head and neck cancers, with inconsistent results.

METHODS

We pooled individual-level data from nine case-control studies of head and neck cancers, including 5,139 cases and 9,028 controls. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI), adjusting for potential confounders.

RESULTS

Caffeinated coffee intake was inversely related with the risk of cancer of the oral cavity and pharynx: the ORs were 0.96 (95% CI, 0.94-0.98) for an increment of 1 cup per day and 0.61 (95% CI, 0.47-0.80) in drinkers of >4 cups per day versus nondrinkers. This latter estimate was consistent for different anatomic sites (OR, 0.46; 95% CI, 0.30-0.71 for oral cavity; OR, 0.58; 95% CI, 0.41-0.82 for oropharynx/hypopharynx; and OR, 0.61; 95% CI, 0.37-1.01 for oral cavity/pharynx not otherwise specified) and across strata of selected covariates. No association of caffeinated coffee drinking was found with laryngeal cancer (OR, 0.96; 95% CI, 0.64-1.45 in drinkers of >4 cups per day versus nondrinkers). Data on decaffeinated coffee were too sparse for detailed analysis, but indicated no increased risk. Tea intake was not associated with head and neck cancer risk (OR, 0.99; 95% CI, 0.89-1.11 for drinkers versus nondrinkers).

CONCLUSIONS

This pooled analysis of case-control studies supports the hypothesis of an inverse association between caffeinated coffee drinking and risk of cancer of the oral cavity and pharynx.

IMPACT

Given widespread use of coffee and the relatively high incidence and low survival of head and neck cancers, the observed inverse association may have appreciable public health relevance.

Risk of colon cancer and coffee, tea, and sugar-sweetened soft drink intake: pooled analysis of prospective cohort studies

BACKGROUND

The relationships between coffee, tea, and sugar-sweetened carbonated soft drink consumption and colon cancer risk remain unresolved.

METHODS

We investigated prospectively the association between coffee, tea, and sugar-sweetened carbonated soft drink consumption and colon cancer risk in a pooled analysis of primary data from 13 cohort studies. Among 731 441 participants followed for up to 6-20 years, 5604 incident colon cancer case patients were identified. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models and then pooled using a random-effects model. All statistical tests were two-sided.

RESULTS

Compared with nonconsumers, the pooled multivariable relative risks were 1.07 (95% CI = 0.89 to 1.30, P(trend) = .68) for coffee consumption greater than 1400 g/d (about six 8-oz cups) and 1.28 (95% CI = 1.02 to 1.61, P(trend) = .01) for tea consumption greater than 900 g/d (about four 8-oz cups). For sugar-sweetened carbonated soft drink consumption, the pooled multivariable relative risk comparing consumption greater than 550 g/d (about 18 oz) to nonconsumers was 0.94 (95% CI = 0.66 to 1.32, P(trend) = .91). No statistically significant between-studies heterogeneity was observed for the highest category of each beverage consumed (P > .20). The observed associations did not differ by sex, smoking status, alcohol consumption, body mass index, physical activity, or tumor site (P > .05).

CONCLUSIONS

Drinking coffee or sugar-sweetened carbonated soft drinks was not associated with colon cancer risk. However, a modest positive association with higher tea consumption is possible and requires further study.

Coffee and tea consumption and endometrial cancer risk in a population-based study in New Jersey

We evaluated the role of tea and coffee and substances added (sugar/honey, creamers, and milk) on endometrial cancer risk in a population-based case-control study in six counties in New Jersey, including 417 cases and 395 controls. Multivariate odds ratios (OR) and 95% confidence intervals (CI) were computed using unconditional logistic regression. There was a moderate inverse association with coffee consumption, with an adjusted OR of 0.65 (95% CI: 0.36-1.17) for women who reported more than two cups/day of coffee compared to none. Tea consumption appeared to increase risk (OR: 1.93; 95% CI: 1.08-3.45), but after including the variables sugar/honey and cream/milk added to tea in the model, the risk estimate was attenuated and no longer statistically significant (OR: 1.77; 95% CI: 0.96-3.28 for those consuming more than one cup/day of tea compared to nonusers). There was a suggestion of a decreased risk associated with green tea, but the confidence interval included one (adjusted OR for one or more cups/week vs. none: 0.75; 95% CI: 0.48-1.18). We found an association with adding sugar/honey to tea, with those adding two or more teaspoons/cup having an OR of 2.66 (95% CI: 1.42-4.98; p for trend <0.01) after adjusting for relevant confounders. For sugar/honey added to coffee the corresponding OR was 1.43 (95% CI: 0.81-2.55). Our results indicate that sugars and milk/cream added to coffee and tea should be considered in future studies evaluating coffee and tea and endometrial cancer risk.

Tea, coffee, carbonated soft drinks and upper gastrointestinal tract cancer risk in a large United States prospective cohort study

The authors investigated the relationship between hot tea, iced tea, coffee and carbonated soft drinks consumption and upper gastrointestinal tract cancers risk in the NIH-AARP Study. During 2,584,953 person-years of follow-up on 481,563 subjects, 392 oral cavity, 178 pharynx, 307 larynx, 231 gastric cardia, 224 gastric non-cardia cancer, 123 Oesophageal Squamous Cell Carcinoma (ESCC) and 305 Oesophageal Adenocarcinoma (EADC) cases were accrued. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated by multivariate-adjusted Cox regression. Compared to non-drinking, the hazard ratio for hot tea intake of > or =1 cup/day was 0.37 (95% CI: 0.20, 0.70) for pharyngeal cancer. The authors also observed a significant association between coffee drinking and risk of gastric cardia cancer (compared to <1 cup/day, the hazard ratio for drinking >3 cups/day was 1.57 (95% CI: 1.03, 2.39)), and an inverse association between coffee drinking and EADC for the cases occurring in the last 3 years of follow-up (compared to <1 cup/day, the hazard ratio for drinking >3 cups/day was 0.54 (95% CI: 0.31, 0.92)), but no association in earlier follow-up. In summary, hot tea intake was inversely associated with pharyngeal cancer, and coffee was directly associated with gastric cardia cancer, but was inversely associated with EADC during some follow-up periods.

Coffee consumption and risk of lung cancer: a meta-analysis

Epidemiologic studies have evaluated the potential association between coffee consumption and lung cancer risk. However, results were inconsistent. To clarify the role of coffee in lung cancer, we conducted a meta-analysis on this topic. We searched PubMed and EMBASE databases (from 1966 to January 2009) and the reference lists of retrieved articles. Study-specific risk estimates were pooled using random-effects model. Five prospective studies and 8 case-control studies involving 5347 lung cancer cases and 104,911 non-cases were included in this meta-analysis. The combined results indicated a significant positive association between highest coffee intake and lung cancer [relative risk (RR)=1.27, 95% confidence interval (CI)=1.04-1.54). Furthermore, an increase in coffee consumption of 2 cups/day was associated with a 14% increased risk of developing lung cancer (RR=1.14, 95% CI=1.04-1.26). In stratified analyses, the highest coffee consumption was significantly associated with increased risk of lung cancer in prospective studies, studies conducted in America and Japan, but borderline significantly associated with decreased risk of lung cancer in non-smokers. In addition, decaffeinated coffee drinking was associated with decreased lung cancer risk, although the number of studies on this topic was relative small. In conclusion, results from this meta-analysis indicate that high or an increased consumption of coffee may increase the risk of lung cancer. Because the residual confounding effects of smoking or other factors may still exist, these results should be interpreted with caution.

Risk factors for lung cancer: a case-control study in Hong Kong women

To identify etiological connections of lung cancer in Chinese women in Hong Kong, who are among the highest in lung cancer incidence and mortality, we conducted a case-control study, in which 279 female lung cancer cases and 322 controls were selected and frequency matched. A variety of information, including dietary habits, occupational history, smoking, domestic environmental exposures, and family history of cancer was collected, and their associations with lung cancer were analyzed with logistic analysis approach. In addition to positive associations with exposures to cooking emissions and to radon at home, smoking and family cancer history, we observed that increasing consumption of meat was linked to a higher risk, whereas consumptions of vegetables had a strong protective effect against lung cancer. Moderate consumption of coffee appeared to be beneficial against the disease. Those never employed and domestic helpers were at a higher risk. The results indicated that environmental exposures, risky personal behaviors, or lifestyle, as well as family cancer aggregation are among important contributors to the high incidence of lung cancer in Hong Kong females.

Total fluid and specific beverage intake and risk of renal cell carcinoma in Canada

BACKGROUND

Intake of total fluids and specific beverages may be associated with the risk of renal cell carcinoma (RCC) through a diluting effect of carcinogens. However, total fluid consumption and RCC risk has not received sufficient examination. In this study, we assessed the roles of total fluid intake and type of beverage intake in the risk of RCC.

METHODS

Mailed questionnaires were completed by 1138 newly diagnosed, histologically confirmed RCC cases and 5039 population controls between 1994 and 1997 in 8 Canadian provinces. Data collection included information on socio-economic status, physical activity, smoking habits, alcoholic and non-alcoholic beverage use, diet, residential history and occupational history. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived through unconditional logistic regression.

RESULTS

Higher total fluid intake was associated with risk of RCC; the OR for the highest versus the lowest quartile was 1.49 (95% CI 1.20-1.85). Intake of total juices and coffee was also related to the risk of RCC; for the highest versus the lowest quartile, the ORs were 1.53 (95% CI 1.18-1.99) and 1.33 (95% CI 1.07-1.66), respectively. These positive associations were stronger in men, but not in women. Higher coffee intake was more strongly associated with RCC in normal weight subjects. In contrast, total intake of alcohol was inversely associated with the risk of RCC. Intake of tap water (not in coffee or tea), bottled water, tea, soft drinks and milk was not related to RCC.

CONCLUSIONS

The risk of RCC for higher intake of total fluids, coffee and juices might involve gender differences.

Coffee drinking and risk of endometrial cancer--a population-based cohort study

Coffee drinking has been reported to have beneficial effects on insulin resistance, which has been directly associated with endometrial cancer. Although a relationship between coffee consumption and endometrial cancer risk is biologically plausible, this hypothesis has been previously explored in only 2 prospective studies, with a small number of cases. We used data from the Swedish Mammography Cohort, a population-based prospective cohort study of 60,634 women. During 17.6 years of follow-up, 677 participants were diagnosed with incident endometrial cancer (adenocarcinoma). We examined the association between self-reported coffee consumption (at baseline 1987-90 and in 1997) and endometrial cancer risk using Cox proportional hazards models. Each additional cup (200 g) of coffee per day was associated with a rate ratio (RR) of 0.90 [95% confidence interval (CI), 0.83-0.97]. In women drinking 4 or more cups of coffee a day, the RR for the risk reduction of endometrial cancer was 0.75 (95% CI, 0.58-0.97) when compared with those who drank 1 cup or less. The association seemed largely confined to overweight and obese women, who showed a respective risk reduction of 12% (95% CI, 0-23%) and 20% (95% CI, 7-31%) for every cup of coffee, but was not observed among normal-weight women. There was a statistically significant interaction between coffee consumption and body mass index (p(interaction) < 0.001). These data indicate that coffee consumption may be associated with decreased risk of endometrial cancer, especially among women with excessive body weight. If confirmed by other prospective studies, these results are of major public health significance.

Trigonelline is a novel phytoestrogen in coffee beans

Drinking coffee has been associated with the development of several endocrine-related cancers. The interpretation of these data has often been limited to the role that caffeine plays. Trigonelline (Trig), a niacin-related compound, is a natural constituent of coffee accounting for approximately 1% dry matter in roasted beans. Studies exploring the effects of this bioactive compound on mammalian cells are limited. The initial purpose of our studies was to determine whether Trig alters the actions of estradiol (E(2)), using proliferation of estrogen-dependent human breast cancer (MCF-7) cells as a model system. When cells were cotreated with suboptimal doses of E(2) (10 pmol/L) and Trig (100 pmol/L), an additive enhancement of MCF-7 growth was observed. In the absence of E(2), Trig stimulated MCF-7 cell proliferation in a dose-responsive manner and significantly enhanced cell growth at concentrations as low as 100 pmol/L. Cotreatment of MCF-7 cells with Trig and ICI 182,780, an estrogen receptor (ER) antagonist, inhibited Trig-induced cell proliferation. Trig treatment also induced activation of estrogen response element reporter assays in MCF-7 cells and increased expression of ER target genes (pS2, progesterone receptor, and cyclin D1) similar to E(2). While our data demonstrate that Trig activates the ER, competitive binding assays showed that Trig does not compete E(2) off of the ER at any concentration. This suggests that Trig is activating the ER through a separate mechanism. Collectively, these data demonstrate that Trig even at low concentrations stimulates MCF-7 cell growth and that this effect is mediated through ER, clearly identifying Trig as a novel phytoestrogen.

Coffee consumption and risk of colorectal cancer: a systematic review and meta-analysis of prospective cohort studies

An inverse association between coffee consumption and the risk of colorectal cancer has been found in several case-control studies, but such an association was not consistent in prospective cohort studies. We conducted a systematic meta-analysis of prospective cohort studies on coffee consumption and colorectal cancer published up to June 2008. We combined relative risks (RR) for colorectal cancer comparing high vs. low categories of coffee consumption using random-effects models. We identified 12 eligible cohort studies, which included 646,848 participants and 5,403 cases for colorectal cancer. The summarized result of the meta-analysis comparing high- vs. low-consumption categories showed no significant effect of coffee consumption on colorectal cancer risk (RR = 0.91; 95% confidence intervals [CI]: 0.81-1.02). The RR was 0.93 (95% CI: 0.71-1.22) when considering 4 studies conducted in the United States of America, 0.91 (95% CI: 0.76-1.10) for 5 studies from Europe, and 0.83 (95% CI: 0.62-1.10) for 3 Japanese studies. No significant differences by sex and cancer-site were found, but there was a slight suggestion of an inverse association between coffee consumption and colon cancer in women (RR = 0.79; 95% CI: 0.60-1.04), especially Japanese women (RR = 0.62; 95% CI: 0.37-1.05). The suggestive inverse associations were slightly stronger in studies that controlled for smoking and alcohol, and in studies with shorter follow-up times. Information on coffee type, its serving size, or brewing method may provide a better understanding of this reassuring result and the real role of coffee on colorectal cancer risk.

Coffee consumption and risk of breast cancer: a metaanalysis

OBJECTIVE

This metaanalysis was conducted to assess the association between coffee consumption and breast cancer risk.

STUDY DESIGN

Relevant studies were identified by searching Medline (1966-May 2008) and the reference lists of retrieved articles. The summary relative risk (RR) with 95% confidence interval (CI) was calculated using a random-effects model.

RESULTS

Nine cohort and 9 case-control studies met the inclusion criteria. The combined RR showed a borderline significant influence of highest coffee consumption (RR, 0.95; 95% CI, 0.90-1.00) or an increment of 2 cups/day of coffee consumption (RR, 0.98; 95% CI, 0.96-1.00) on the risk of breast cancer. In stratified analysis, borderline significant associations were observed among cohort and case-control studies and studies conducted in Europe and the United States. However, no significant association was noted among studies conducted in Asia.

CONCLUSION

Our findings suggest a possible influence of high coffee consumption or an increased coffee consumption on the risk of breast cancer.

Alcohol, coffee, and bladder cancer risk: a review of epidemiological studies

The objective was to review epidemiological studies that evaluated the association between consumption of coffee and alcohol and urinary bladder cancer. We searched the Medline database for observational studies of bladder neoplasms that included information on coffee or alcohol drinking, and looked for papers quoted as references in reviews of risk factors for bladder cancer and in studies that had been selected for inclusion. Results from epidemiological studies allow excluding a strong association between coffee and bladder cancer. Several studies reported a moderate increase in risk in coffee drinkers as compared with nondrinkers, but no trend with dose has been established. Epidemiological data on alcohol drinking and bladder cancer are suggestive of no association, although findings were not always consistent. For both habits, an explanation of the moderate increase in risk observed in some investigations might be attributed to residual confounding by smoking, or to an association between alcohol, coffee, and yet unidentified risk factors for bladder cancer.

Coffee and alcohol consumption and bladder cancer

Epidemiological studies on coffee, alcohol and bladder cancer risk published up to 2007 were reviewed. Coffee drinkers have a moderately higher relative risk of bladder cancer compared to non-drinkers. The association may partly be due to residual confounding by smoking or dietary factors, but the interpretation remains open to discussion, although the absence of dose and duration-risk relations weighs against the presence of a causal association. Most studies of alcohol and bladder cancer found no association, with some studies finding a direct and other an inverse one. This again may be due to differential confounding effect of tobacco smoking--the major risk factor for bladder cancer--in various populations. Thus, epidemiological findings on the relation between alcohol drinking and bladder cancer exclude any meaningful association.

Coffee drinking and endometrial cancer risk: a metaanalysis of observational studies

We conducted a metaanalysis of published studies on the relation between coffee drinking and endometrial cancer risk, which included 2 cohort (201 cases) and 7 case-control studies (2409 cases). The summary relative risk (RR) for coffee drinkers vs nondrinkers was 0.80 (95% confidence interval [CI], 0.68-0.94), with significant heterogeneity between studies. Compared with nondrinkers, the summary RR was 0.87 (95% CI, 0.78-0.97) for low-to-moderate coffee drinkers and 0.64 (95% CI, 0.48-0.86) for heavy coffee drinkers. The summary RR for an increase of 1 cup/d was 0.93 (95% CI, 0.89-0.97), which suggests an inverse relation between coffee and endometrial cancer. However, the causality must be confirmed.

Coffee, green tea, and caffeine consumption and subsequent risk of bladder cancer in relation to smoking status: a prospective study in Japan

Coffee and caffeine consumption are thought to increase the risk of bladder cancer. However, few studies have stratified this risk by smoking status, which is a potential confounder. Here, we investigated the association between coffee, green tea (another major source of caffeine), and caffeine, and bladder cancer incidence in relation to smoking status. We conducted a population-based prospective study in a cohort of Japanese, comprising a total of 49 566 men and 54 874 women aged 40–69 years who reported their coffee and green tea consumption at baseline. During follow-up from 1990 through 2005, 164 men and 42 women were newly diagnosed with bladder cancer. Cigarette smoking was associated with an increased risk of bladder cancer, with a strong dose–response relationship. Coffee was positively associated with bladder cancer risk in men, without statistical significance. When stratified by smoking status, coffee and caffeine consumption were associated with an increased risk of bladder cancer in never- or former-smoking men, with hazard ratios (95% confidence interval) in the highest categories of coffee (one or more cups per day) and caffeine consumption compared with the lowest of 2.24 (95% CI = 1.21–4.16) and 2.05 (95% CI = 1.15–3.66), respectively. In conclusion, cigarette smoking was confirmed as a risk factor for bladder cancer. Coffee and caffeine may be associated with an increased bladder cancer risk in never or former smokers among Japanese men.

Coffee consumption and the risk of oral, pharyngeal, and esophageal cancers in Japan: the Miyagi Cohort Study

An inverse association between coffee consumption and the risk of oral, pharyngeal, and esophageal cancers has been suggested in case-control studies, but few results from prospective studies are available. Data from the Miyagi Cohort Study in Japan were used to clarify the association between coffee consumption and the risk of these cancers. Information about coffee consumption was obtained from self-administered food frequency questionnaires in 1990. Among 38,679 subjects aged 40-64 years with no previous history of cancer, 157 cases of oral, pharyngeal, and esophageal cancers were identified during 13.6 years of follow-up. Hazard ratios were estimated by the Cox proportional hazards regression model. The risk of oral, pharyngeal, and esophageal cancers was inversely associated with coffee consumption. The multivariate-adjusted hazard ratio of these cancers for > or =1 cups of coffee per day compared with no consumption was 0.51 (95% confidence interval: 0.33, 0.77). This inverse association was consistent regardless of sex and cancer site and was observed both for subjects who did not drink or smoke and for those who currently drank or smoked at baseline. In conclusion, coffee consumption was associated with a lower risk of oral, pharyngeal, and esophageal cancers, even in the group at high risk of these cancers.

Hypoxia-adenosinergic immunosuppression: tumor protection by T regulatory cells and cancerous tissue hypoxia

Cancerous tissue protection from tumor-recognizing CD8(+) and CD4(+) T cells (antitumor T cells) limits the therapeutic potential of immunotherapies. We propose that tumor protection is to a large extent due to (a) inhibition of antitumor T cells by hypoxia-driven accumulation of extracellular adenosine in local tumor microenvironment and due to (b) T regulatory cell-produced extracellular adenosine. The adenosine triggers the immunosuppressive signaling via intracellular cyclic AMP-elevating A2A adenosine receptors (A2AR) on antitumor T cells. In addition, the activated antitumor T cells in hypoxic tumor microenvironment could be inhibited by elevated levels of immunosuppressive hypoxia-inducible factor-1alpha. Complete rejection or tumor growth retardation was observed when A2AR has been genetically eliminated or antagonized with synthetic drug or with natural A2AR antagonist 1,3,7-trimethylxanthine (caffeine). The promising strategy may be in combining the anti-hypoxia-adenosinergic treatment that prevents inhibition of antitumor T cells by tumor-produced and T regulatory cell-produced adenosine with targeting of other negative regulators, such as CTL antigen-4 blockade. Observations of tumor rejection in mice and massive prospective epidemiologic studies support the feasibility of anti-hypoxia-adenosinergic combined immunotherapy.