Consumption of filtered and boiled coffee and the risk of incident cancer: a prospective cohort study

Coffee consumption and the risk of malignant melanoma in the Norwegian Women and Cancer (NOWAC) Study

Background

Coffee contains biologically-active substances that suppress carcinogenesis in vivo, and coffee consumption has been associated with a lower risk of malignant melanoma. We studied the impact of total coffee consumption and of different brewing methods on the incidence of malignant melanoma in a prospective cohort of Norwegian women.

Methods

We had baseline information on total coffee consumption and consumption of filtered, instant, and boiled coffee from self-administered questionnaires for 104,080 women in the Norwegian Women and Cancer (NOWAC) Study. We also had follow-up information collected 6–8 years after baseline. Multiple imputation was used to deal with missing data, and multivariable Cox regression models were used to calculate hazard ratios (HR) for malignant melanoma by consumption category of total, filtered, instant, and boiled coffee.

Results

During 1.7 million person-years of follow-up, 762 cases of malignant melanoma were diagnosed. Compared to light consumers of filtered coffee (≤1 cup/day), we found a statistically significant inverse association with low-moderate consumption (>1–3 cups/day, HR = 0.80; 95 % confidence interval [CI] 0.66–0.98) and high-moderate consumption of filtered coffee (>3–5 cups/day, HR = 0.77; 95 % CI 0.61–0.97) and melanoma risk (p_trend = 0.02). We did not find a statistically significant association between total, instant, or boiled coffee consumption and the risk of malignant melanoma in any of the consumption categories.

Conclusions

The data from the NOWAC Study indicate that a moderate intake of filtered coffee could reduce the risk of malignant melanoma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2586-5) contains supplementary material, which is available to authorized users.

Coffee consumption and the risk of cutaneous melanoma: a meta-analysis

PURPOSE

Results from epidemiologic studies on coffee consumption and the risk of cutaneous melanoma are inconsistent. We conducted a meta-analysis to assess the associations between the consumption of total coffee, caffeinated coffee and decaffeinated coffee and the risk of cutaneous melanoma, respectively.

METHODS

A literature search was performed in PubMed, Web of Science and EMBASE for relevant articles published up to August 2015. Pooled relative risks (RRs) with 95 % confidence intervals (CIs) were calculated with a random-effects model. Dose-response relationship was assessed by restricted cubic spline.

RESULTS

Twelve studies involving 832,956 participants for total coffee consumption, 5 studies involving 717,151 participants for caffeinated coffee consumption and 6 studies involving 718,231 participants for decaffeinated coffee consumption were included in this meta-analysis. Compared with the lowest level of consumption, the pooled RRs were 0.80 (95 % CI 0.69-0.93, I (2) = 53.5 %), 0.85 (95 % CI 0.71-1.01, I (2) = 65.0 %) and 0.92 (95 % CI 0.81-1.05, I (2) = 0.0 %) for the consumption of total coffee, caffeinated coffee and decaffeinated coffee, respectively. In subgroup analysis by study design, the pooled RRs in cohort studies and case-control studies were 0.83 (95 % CI 0.72-0.97) and 0.74 (95 % CI 0.51-1.07) for total coffee consumption, respectively. Dose-response analysis suggested cutaneous melanoma risk decreased by 3 % [0.97 (0.93-1.00)] and 4 % [0.96 (0.92-1.01)] for 1 cup/day increment of total coffee and caffeinated coffee consumption, respectively.

CONCLUSIONS

This meta-analysis suggests that coffee consumption may reduce the risk of cutaneous melanoma.

Coffee Consumption and Melanoma: A Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

Laboratory and animals studies have suggested a possible protective effect of coffee consumption on the development of melanoma. However, the results of epidemiological studies investigating this association have been inconclusive.

OBJECTIVE

A systematic review and meta-analysis of published studies was conducted to evaluate any association between coffee consumption and melanoma.

METHODS

Observational studies were searched for in MEDLINE, EMBASE, and the Cochrane Central Register from inception to September 1, 2015. The Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines were followed in conducting this study.

RESULTS

We identified nine observational studies with a total of 927,173 study participants, of which 3787 had melanoma. With random-effects modeling, the pooled relative risks (RR) for melanoma among regular coffee drinkers was 0.75 (95 % confidence interval [CI] 0.63-0.89, p = 0.001) compared with controls. Visual inspection of a funnel plot suggested publication bias, although Egger's test (p = 0.981) delineated no small-study effects. The pooled relative risks for melanoma among decaffeinated coffee drinkers was, however, not statistically significant at 0.92 (95 % CI 0.82-1.05, p = 0.215).

CONCLUSION

There is some evidence for the beneficial effects of regular coffee consumption on melanoma. More prospective cohort studies with systematic quantification of coffee consumption would be necessary to further elucidate this association.

Coffee Consumption and Pancreatic Cancer Risk: An Update Meta-analysis of Cohort Studies

BACKGROUND & OBJECTIVE

The results of epidemiologic studies on the relationship between the coffee consumption and pancreatic cancer risk were inconsistent. Thus, we performed an update meta-analysis of cohort studies to quantitatively summarize the association between coffee consumption and pancreatic cancer risk.

METHODS

We searched CBM (China Biology Medicine disc) and MEDLINE for studies of coffee consumption and pancreatic cancer risk up to June 2015. A total of 20 cohort studies were identified in this meta-analysis, and we analyzed these studies using random effects model. The dose-response analysis was conducted too.

RESULTS

The overall relative risk (RR) for highest coffee consumption versus lowest coffee consumption was 0.75 (95% Confidence Interval (CI), 0.63-0.86). Statistic significant heterogeneity was found among these studies (I (2) =37.8%, P for heterogeneity =0.045). The pooled RR for increment of 1 cup/day of coffee consumption was 0.99 (95%CI, 0.96-1.03) for the nine studies, without statistically significant.

CONCLUSIONS

High coffee consumption is associated with a reduced pancreatic cancer risk. However, the result should be accepted with caution, due to the potential confounder and bias could not be excluded. Further well designed studies are needed to confirm the finding.

Coffee consumption and the risk of cancer in the Norwegian Women and Cancer (NOWAC) Study

An association between coffee consumption and cancer has long been investigated. Coffee consumption among Norwegian women is high, thus this is a favorable population in which to study the impact of coffee on cancer incidence. Information on coffee consumption was collected from 91,767 women at baseline in the Norwegian Women and Cancer Study. These information were applied until follow-up information on coffee consumption, collected 6-8 years after baseline, became available. Multiple imputation was performed as a method for dealing with missing data. Multivariable Cox regression models were used to calculate hazard ratios (HR) for breast, colorectal, lung, and ovarian cancer, as well as cancer at any site. We observed a 17 % reduced risk of colorectal cancer (HR = 0.83, 95 % CI 0.70-0.98, p trend across categories of consumption = 0.10) and a 9 % reduced risk of cancer at any site (HR = 0.91, 95 % CI 0.86-0.97, p trend = 0.03) in women who drank more than 3 and up to 7 cups/day, compared to women who drank ≤1 cup/day. A significantly increased risk of lung cancer was observed with a heavy coffee consumption (>7 vs. ≤1 cup/day HR = 2.01, 95 % CI 1.47-2.75, p trend < 0.001). This was most likely caused by residual confounding due to smoking, as no statistically significant association was observed in never smokers (>5 vs. ≤1 cup/day HR = 1.42, 95 % CI 0.44-4.57, p trend = 0.30). No significant association was found between coffee consumption and the risk of breast or ovarian cancer. In this study, coffee consumption was associated with a modest reduced risk of cancer at any site. Residual confounding due to smoking may have contributed to the positive association between high coffee consumption and the risk of lung cancer.

Higher Caffeinated Coffee Intake Is Associated with Reduced Malignant Melanoma Risk: A Meta-Analysis Study

Background

Several epidemiological studies have determined the associations between coffee intake level and skin cancer risk; however, the results were not yet conclusive. Herein, we conducted a systematic review and meta-analysis of the cohort and case-control studies for the association between coffee intake level and malignant melanoma (MM) risk.

Methods

Studies were identified through searching the PubMed and MEDLINE databases (to November, 2015). Study-specific risk estimates were pooled under the random-effects model.

Results

Two case-control studies (846 MM patients and 843 controls) and five cohort studies (including 844,246 participants and 5,737 MM cases) were identified. For caffeinated coffee, the pooled relative risk (RR) of MM was 0.81 [95% confidential interval (95% CI) = 0.68–0.97; P-value for Q-test = 0.003; I² = 63.5%] for those with highest versus lowest quantity of intake. In the dose-response analysis, the RR of MM was 0.955 (95% CI = 0.912–0.999) for per 1 cup/day increment of caffeinated coffee consumption and linearity dose-response association was found (P-value for nonlinearity = 0.326). Strikingly, no significant association was found between the decaffeinated coffee intake level and MM risk (pooled RR = 0.92, 95% CI = 0.81–1.05; P-value for Q-test = 0.967; I² = 0%; highest versus lowest quantity of intake).

Conclusions

This meta-analysis suggested that caffeinated coffee might have chemo-preventive effects against MM but not decaffeinated coffee. However, larger prospective studies and the intervention studies are warranted to confirm these findings.

Coffee consumption and the risk of incident gastric cancer--A meta-analysis of prospective cohort studies

As several epidemiological studies on the association of coffee consumption with gastric cancer risk have produced inconsistent results, this meta-analysis was designed to synthesize current evidence of this potential relationship. We searched PubMed, EMBASE, and the Cochrane Library up to September 2014 to retrieve relevant articles. Prospective cohort studies were included if the relative risks (RRs) or hazard ratios and 95% confidence intervals (CIs) for gastric cancer according to coffee consumption were reported. Fixed- or random-effects models were used based on heterogeneity. The search yielded 13 eligible cohort studies of 3484 incident gastric cancer patients from among 1,324,559 participants. A significantly increased risk was found between gastric cardia cancer and coffee consumption (RR = 1.50, 95% CI: 1.09-2.07). Compared with Europeans (RR = 1.12, 95% CI: 0.86-1.46) and Asians (RR = 0.96, 95% CI: 0.72-1.27), Americans (RR = 1.36, 95% CI: 1.06-1.74) demonstrated a significantly positive association. However, the significant differences of the pooled results vanished after adjusting for smoking or body mass index. Our meta-analysis results suggest that a high level of coffee consumption is a risk factor for gastric cancer. However, these results should not be overinterpreted because residual confounding effects of other factors could exist.

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

Background

Several observational studies suggest that coffee consumption may be associated with an increased risk of gastric cancer, but the results are inconsistent. We conducted a meta-analysis to evaluate the relationship of coffee consumption with gastric cancer risk and quantify the dose–response relationship between them.

Methods

Relevant prospective studies were identified by a search of PubMed, Embase, and Web of Science to May 2015 and by reviewing the references of retrieved articles. Two independent reviewers extracted data and performed the quality assessment. A random-effects model was used to calculate the pooled risk estimates and 95 % confidence intervals (CI). The heterogeneity was assessed using the I² statistic. Publication bias was assessed by using funnel plot, the Begg test and the Egger test.

Results

Thirteen prospective cohort studies with 20 independent reports involving 3,368 patients with gastric cancer and 1,372,811 participants during a follow-up period ranging from 4.3–8 years were included. Compared with the lowest consumption level of coffee, the pooled relative risk (RR) was 1.13 (95 % CI: 0.94–1.35). The dose–response analysis indicated that, the RR of gastric cancer was 1.03 (95 % CI; 0.95–1.11) for per 3 cups/day of coffee consumption. Any nonlinear association of gastric cancer risk with coffee consumption was not found (P for nonlinearity = 0.68). Subgroup analyses indicated that the pooled RR for participants from the United States comparing the highest with the lowest coffee consumption was 1.36 (95 % CI, 1.06–1.75, I² = 0 %). In addition, people with higher coffee consumption was associated with 25 % higher risk of gastric cancer in equal to or less than 10 years follow-up group (RR = 1.25; 95 % CI, 1.01–1.55, I² = 0 %). Visual inspection of a funnel plot and the Begg’s and the Egger’s tests did not indicate evidence of publication bias.

Conclusions

This meta-analysis does not support the hypothesis that coffee consumption is associated with the risk of gastric cancer. The increased risk of gastric cancer for participants from the United States and equal to or less than 10 years follow-up group associated with coffee consumption warrant further studies.

A prospective study of coffee intake and pancreatic cancer: results from the NIH-AARP Diet and Health Study

BACKGROUND

Evidence evaluating the association between type of coffee intake (caffeinated, decaffeinated) and risk of pancreatic cancer is limited.

METHODS

In the US NIH-AARP Diet and Health Study, we used Cox proportional hazards regression to estimate hazard ratios and 95% confidence intervals (CIs) for coffee intake and risk of pancreatic cancer among 457 366 US adults.

RESULTS

Over 4 155 256 person-years of follow-up, 1541 incident first primary pancreatic cancers occurred. Following detailed adjustment for tobacco smoking history, risk estimates for coffee drinking were not statistically significant; compared with never drinkers of coffee, the hazard ratios (95% CI) were 1.05 (0.85-1.30), 1.06 (0.86-1.31), 1.03 (0.85-1.25), 1.00 (0.79-1.25), and 1.24 (0.93-1.65) for <1, 1, 2-3, 4-5, and ≥6 cups per day, respectively (P-value for trend 0.46). The observed null association was consistent across all examined strata (sex, smoking status, coffee caffeination, and prevalent diabetes).

CONCLUSIONS

In a prospective study of coffee intake with the largest number of pancreatic cancer cases to date, we did not observe an association between total, caffeinated, or decaffeinated coffee intake and pancreatic cancer.

Long-Term Coffee Consumption and Risk of Gastric Cancer: A PRISMA-Compliant Dose-Response Meta-Analysis of Prospective Cohort Studies

Association between coffee consumption and gastric cancer risk remains controversial. Hence, we performed a meta-analysis to investigate and quantify the potential dose-response association between long-term coffee consumption and risk of gastric cancer.Pertinent studies were identified by searching PubMed and Embase from January 1996 through February 10, 2015 and by reviewing the reference lists of retrieved publications. Prospective cohort studies in which authors reported effect sizes and corresponding 95% confidence intervals (CIs) of gastric cancer for 3 or more categories of coffee consumption were eligible. Results from eligible studies were aggregated using a random effect model. All analyses were carried out using the STATA 12.0 software.Nine studies involving 15 independent prospective cohorts were finally included. A total of 2019 incident cases of gastric cancer were ascertained among 1,289,314 participants with mean follow-up periods ranging from 8 to 18 years. No nonlinear relationship of coffee consumption with gastric cancer risk was indentified (P for nonlinearity = 0.53; P for heterogeneity = 0.004). The linear regression model showed that the combined relative risk (RR) of every 3 cups/day increment of total coffee consumption was 1.07 (95% CI = 0.95-1.21). Compared with the lowest category of coffee consumption, the RR of gastric cancer was 1.18 (95% CI = 0.90-1.55) for the highest (median 6.5 cups/day) category, 1.06 (95% CI = 0.85-1.32) for the second highest category (median 3.5 cups/day), and 0.97 (95% CI = 0.79-1.20) for the third highest category (median 1.5 cups/day). Subgroup analysis showed an elevated risk in the US population (RR = 1.36, 95% CI = 1.06-1.75) and no adjustment for smoking (RR = 1.67, 95% CI = 1.08-2.59) for 6.5 cups/day.Current evidence indicated there was no nonlinear association between coffee consumption and gastric cancer risk. However, high coffee consumption (more than 6.5 cups/day) might increase the risk of gastric cancer in the US population. More high quality studies were warranted to further investigate the association.

Coffee consumption and risk of endometrial cancer: a dose-response meta-analysis of prospective cohort studies

This is a dose-response (DR) meta-analysis to evaluate the association of coffee consumption on endometrial cancer (EC) risk. A total 1,534,039 participants from 13 published articles were added in this meta-analysis. The RR of total coffee consumption and EC were 0.80 (95% CI: 0.74–0.86). A stronger association between coffee intake and EC incidence was found in patients who were never treated with hormones, 0.60 (95% CI: 0.50–0.72), and subjects with a BMI ≥25 kg/m², 0.57 (95% CI: 0.46–0.71). The overall RRs for caffeinated and decaffeinated coffee were 0.66 (95% CI: 0.52–0.84) and 0.77 (95% CI: 0.63–0.94), respectively. A linear DR relationship was seen in coffee, caffeinated coffee, decaffeinated coffee and caffeine intake. The EC risk decreased by 5% for every 1 cup per day of coffee intake, 7% for every 1 cup per day of caffeinated coffee intake, 4% for every 1 cup per day of decaffeinated intake of coffee, and 4% for every 100 mg of caffeine intake per day. In conclusion, coffee and intake of caffeine might significantly reduce the incidence of EC, and these effects may be modified by BMI and history of hormone therapy.

Coffee consumption and incidence of lung cancer in the NIH-AARP Diet and Health Study

BACKGROUND

Coffee drinkers had a higher risk of lung cancer in some previous studies, but as heavy coffee drinkers tend to also be cigarette smokers, such findings could be confounded. Therefore, we examined this association in the nearly half a million participants of the US NIH-AARP Diet and Health Study.

METHODS

Typical coffee intake and smoking history were queried at baseline. During 4 155 256 person-years of follow-up, more than 9000 incident lung cancer cases occurred. We used Cox proportional hazards regression to estimate hazard ratios (HRs)and 95% confidence intervals for coffee intake and subsequent incidence of lung cancer. We also comprehensively adjusted for tobacco smoking and examined associations by detailed strata of tobacco use.

RESULTS

Coffee drinkers were far more likely to smoke than non-drinkers. Although coffee drinking was associated with lung cancer in age- and sex- adjusted models (HR for ≥ 6 cups/day compared with none: 4.56, 4.08-5.10), this association was substantially attenuated after adjusting for smoking (HR: 1.27, 1.14-1.42). Similar findings were observed for each different histological type of lung cancer, and for participants drinking predominantly caffeinated or decaffeinated coffee. Little evidence for an association was observed in our stratified analyses, either within never smokers or in most categories of tobacco use.

CONCLUSIONS

Coffee drinking was positively associated with lung cancer in our study, although the association was substantially attenuated after adjustment for tobacco smoking. As our adjustment for lifetime tobacco use was imperfect, it is likely that the remaining association is due to residual confounding by smoking, although other explanations are possible.

Effect of coffee consumption on the risk of gastric cancer: a systematic review and meta-analysis of prospective cohort studies

Background and Objectives

Results from observational epidemiologic studies on the relationship between coffee consumption and gastric cancer are inconsistent and inconclusive. To assess the association between coffee consumption and the risk of gastric cancer, we summarized evidence from prospective cohort studies.

Methods

Relevant studies were retrieved through computer searches (PubMed, EmBase and the Cochrane Library) and a review of references up to December 2014. The quality of the included studies was evaluated by Newcastle-Ottawa quality assessment scale. We used a meta-analytic approach to estimate overall hazard ratios (HRs) and 95% confidence intervals (CIs) for regular coffee drinkers versus individuals who seldom drank coffee. Sensitivity analysis and subgroup analysis were performed to assess the reliability of our results. A dose–response analysis was performed to assess the risk of gastric cancer based on the level of coffee consumption.

Results

Nine prospective cohort studies involving 1,250,825 participants and 3027 gastric cancer cases were included in this meta-analysis. The pooled HR of gastric cancer for the study-specific regularly versus seldom coffee drinking categories was 1.05 (95% CI, 0.88 to 1.25) with significant heterogeneity across studies (I² = 74.0%, P = 0.000). After the sensitivity analysis, three studies were deleted; however the association remained insignificant (HR, 0.99; 95% CI, 0.91 to 1.08). Subgroup analysis by anatomic location showed a risk for coffee consumption associated with cardia cancer (HR, 1.23; 95% CI, 1.04 to 1.45; heterogeneity, I² = 36.4, P = 0.207). In the dose–response analysis, there was no significant association between coffee intake (in cups) and the risk of gastric cancer (P for linearity trend and non-linearity > 0.05).

Conclusion

Our meta-analysis demonstrated that coffee consumption was not associated with overall gastric cancer risk; however, coffee consumption may be a risk factor for gastric cardia cancer.

Prospective study of breast cancer in relation to coffee, tea and caffeine in Sweden

Studies of coffee and tea consumption and caffeine intake as risk factors for breast cancer are inconclusive. We assessed coffee and tea consumption, caffeine intake, and possible confounding factors among 42,099 women from the Swedish Women's Lifestyle and Health study, the participants of which were aged 30-49 years at enrollment in 1991-1992. Complete follow-up for breast cancer incidence was performed through 2012 via linkage to national registries. Poisson regression models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for breast cancer. During follow-up 1,395 breast cancers were diagnosed. The RR was 0.97 (95% CI 0.94-0.99) for a 1-unit increase in cups of coffee/day, 1.14 (95% CI 1.05-1.24) for a 1-unit increase in cups of tea/day, and 0.97 (95% CI 0.95-1.00) for a 100 mg/day increase in caffeine intake. Although the RR for no consumption (RR = 0.86, 95% CI 0.69-1.08), a group with a relatively small number of women, was not statistically significant, women with higher consumption had a decreased breast cancer risk (3-4 cups/day: RR = 0.87, 95% CI 0.76-1.00; ≥5 cups/day: RR = 0.81, 95% CI 0.70-0.94) compared to women consuming 1-2 cups of coffee/day. Compared to no consumption, women consuming >1 cups tea/day showed an increased breast cancer risk (RR = 1.19, 95% CI 1.00-1.42). Similar patterns of estimates were observed for breast cancer risk overall, during pre- and postmenopausal years, and for ER+ or PR+ breast cancer, but not for ER- and PR- breast cancer. Our findings suggest that coffee consumption and caffeine intake is negatively associated with the risk of overall and ER+/PR- breast cancer, and tea consumption is positively associated with the risk of overall and ER+/PR+ breast cancer.

Coffee consumption and risk of gastric cancer: an updated meta-analysis

OBJECTIVES

The aim of this study was to perform an updated review to evaluate the effect of coffee consumption on the risk of gastric cancer.

METHODS

We searched the PubMed and Embase database up to October 14th, 2013. Risk ratio (RR) and corresponding 95% confidence intervals (CIs) for the risk of gastric cancer were used as effect sizes. Overall effect sizes were derived using a fixed-effects model or a random-effects model when appropriate. Then in subgroup analyses, the data were reanalyzed, which were stratified by gender, area and follow-up time.

RESULTS

A total of 8 separate studies, including 312,993 volunteers (among them 1429 were diagnosed with gastric cancer in 10-18 years' follow-up), were considered in the meta-analysis. The overall estimate of coffee consumption on the risk of gastric cancer showed a pooled RR of 1.24 (95% CI: 1.03-1.49; P=0.026). In subgroup analyses, the pooled RR of gastric cancer was 1.36 (95% CI: 1.06-1.75) for USA volunteers and 1.29 (95% CI: 1.05-1.59) for people with more than 15-year follow-up time. The sensitivity analysis proved the stability and credibility of our results, and there was no significant bias (Begg's test P=0.640, Egger's test P=0.600) among the studies.

CONCLUSIONS

It indicated that coffee consumption was associated with the development of gastric cancer. More coffee drinking could result in the increased risk of gastric cancer.

Total, caffeinated and decaffeinated coffee and tea intake and gastric cancer risk: results from the EPIC cohort study

Prospective studies examining the association between coffee and tea consumption and gastric cancer risk have shown inconsistent results. We investigated the association between coffee (total, caffeinated and decaffeinated) and tea consumption and the risk of gastric cancer by anatomical site and histological type in the European Prospective Investigation into Cancer and Nutrition study. Coffee and tea consumption were assessed by dietary questionnaires at baseline. Adjusted hazard ratios (HRs) were calculated using Cox regression models. During 11.6 years of follow up, 683 gastric adenocarcinoma cases were identified among 477,312 participants. We found no significant association between overall gastric cancer risk and consumption of total coffee (HR 1.09, 95%-confidence intervals [CI]: 0.84-1.43; quartile 4 vs. non/quartile 1), caffeinated coffee (HR 1.14, 95%-CI: 0.82-1.59; quartile 4 vs. non/quartile 1), decaffeinated coffee (HR 1.07, 95%-CI: 0.75-1.53; tertile 3 vs. non/tertile 1) and tea (HR 0.81, 95%-CI: 0.59-1.09; quartile 4 vs. non/quartile 1). When stratified by anatomical site, we observed a significant positive association between gastric cardia cancer risk and total coffee consumption per increment of 100 mL/day (HR 1.06, 95%-CI: 1.03-1.11). Similarly, a significant positive association was observed between gastric cardia cancer risk and caffeinated coffee consumption (HR 1.98, 95%-CI: 1.16-3.36, p-trend=0.06; quartile 3 vs. non/quartile 1) and per increment of 100 mL/day (HR 1.09, 95%-CI: 1.04-1.14). In conclusion, consumption of total, caffeinated and decaffeinated coffee and tea is not associated with overall gastric cancer risk. However, total and caffeinated coffee consumption may be associated with an increased risk of gastric cardia cancer. Further prospective studies are needed to rule out chance or confounding.

Tea and coffee and risk of endometrial cancer: cohort study and meta-analysis

BACKGROUND

Previous reports, mostly from retrospective studies, suggested possible protective effects of both tea and coffee against endometrial cancer, but recent reports from prospective studies generally showed weaker or null associations.

OBJECTIVES

We investigated endometrial cancer risk in relation to tea and coffee consumption in a large prospective study and did a meta-analysis of published results.

DESIGN

Daily consumption of tea and coffee was recorded in 560,356 participants (without a hysterectomy) in the UK Million Women Study of whom 4067 women developed endometrial cancer during 5.2 million person-years of follow up (average: 9.3 y per woman).

RESULTS

With the use of Cox proportional hazards regression, we showed no significant association between endometrial cancer risk and consumption of either tea (multivariate adjusted RR per cup daily: 1.00; 95% CI: 0.98, 1.02) or coffee (RR per cup daily: 0.98; 95% CI: 0.96, 1.01). Our meta-analyses showed no significant association between endometrial cancer risk and tea consumption and a weak association for coffee consumption in prospective studies, but there may have been selective publication of only part of the evidence.

CONCLUSIONS

There is little or no association between tea consumption and endometrial cancer risk. If there is any association with coffee consumption, it appears to be weak.

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

This meta-analysis was conducted to assess the association between coffee consumption and prostate cancer risk. Thirteen cohort studies with 34,105 cases and 539,577 participants were included in the meta-analysis. The summary relative risks (RRs) with 95% confidence intervals (CIs) for different coffee intake levels were calculated. Dose-response relationship was assessed using generalized least square trend estimation. The pooled RR for the highest vs. lowest coffee intake was 0.90 (95% CI: 0.85-0.95), with no significant heterogeneity across studies (P = 0.267; I(2) = 17.5%). The dose-response analysis showed a lower cancer risk decreased by 2.5% (RR = 0.975; 95% CI: 0.957-0.995) for every 2 cups/day increment in coffee consumption. Stratifying by geographic region, there was a statistically significant protective influence of coffee on prostate cancer risk among European populations. In subgroup analysis of prostate cancer grade, the summary RRs were 0.89 (95% CI: 0.83-0.96) for nonadvanced, 0.82 (95% CI: 0.61-1.10) for advanced and 0.76 (95% CI: 0.55-1.06) for fatal diseases. Our findings suggest that coffee consumption may be associated with a reduced risk of prostate cancer and it also has an inverse association with nonadvanced prostate cancer. Because of the limited number of studies, more prospective studies with large sample size are needed to confirm this association.

Coffee and tea consumption and risk of pre- and postmenopausal breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort study

INTRODUCTION

Specific coffee subtypes and tea may impact risk of pre- and post-menopausal breast cancer differently. We investigated the association between coffee (total, caffeinated, decaffeinated) and tea intake and risk of breast cancer.

METHODS

A total of 335,060 women participating in the European Prospective Investigation into Nutrition and Cancer (EPIC) Study, completed a dietary questionnaire from 1992 to 2000, and were followed-up until 2010 for incidence of breast cancer. Hazard ratios (HR) of breast cancer by country-specific, as well as cohort-wide categories of beverage intake were estimated.

RESULTS

During an average follow-up of 11 years, 1064 premenopausal, and 9134 postmenopausal breast cancers were diagnosed. Caffeinated coffee intake was associated with lower risk of postmenopausal breast cancer: adjusted HR=0.90, 95% confidence interval (CI): 0.82 to 0.98, for high versus low consumption; Ptrend=0.029. While there was no significant effect modification by hormone receptor status (P=0.711), linear trend for lower risk of breast cancer with increasing caffeinated coffee intake was clearest for estrogen and progesterone receptor negative (ER-PR-), postmenopausal breast cancer (P=0.008). For every 100 ml increase in caffeinated coffee intake, the risk of ER-PR- breast cancer was lower by 4% (adjusted HR: 0.96, 95% CI: 0.93 to 1.00). Non-consumers of decaffeinated coffee had lower risk of postmenopausal breast cancer (adjusted HR=0.89; 95% CI: 0.80 to 0.99) compared to low consumers, without evidence of dose-response relationship (Ptrend=0.128). Exclusive decaffeinated coffee consumption was not related to postmenopausal breast cancer risk, compared to any decaffeinated-low caffeinated intake (adjusted HR=0.97; 95% CI: 0.82 to 1.14), or to no intake of any coffee (HR: 0.96; 95%: 0.82 to 1.14). Caffeinated and decaffeinated coffee were not associated with premenopausal breast cancer. Tea intake was neither associated with pre- nor post-menopausal breast cancer.

CONCLUSIONS

Higher caffeinated coffee intake may be associated with lower risk of postmenopausal breast cancer. Decaffeinated coffee intake does not seem to be associated with breast cancer.

Boiled coffee consumption and the risk of prostate cancer: follow-up of 224,234 Norwegian men 20-69 years

BACKGROUND

There is insufficient epidemiological evidence on the relationship between type of coffee and the risk of prostate cancer.

METHODS

The risk of prostate cancer by use of boiled vs not boiled coffee were assessed in a prospective study of 224,234 men 20-69 years. 5740 incident prostate cancers were identified.

RESULTS

With no coffee as reference group the hazard ratios of <1-4, 5-8 and 9+ cups per day of boiled coffee only were 0.84 (0.73-0.96), 0.80 (0.70-0.92) and 0.66 (0.55-0.80), P-trend=0.00. The corresponding figures for not boiled coffee were 0.89 (0.80-0.99), 0.91 (0.81-1.02) and 0.86 (0.74-1.00), P-trend=0.22.

CONCLUSION

An inverse relationship between number of cups per day and the risk of prostate cancer was present only for the boiled coffee type.

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.

High coffee consumption and different brewing methods in relation to postmenopausal endometrial cancer risk in the Norwegian women and cancer study: a population-based prospective study

Background

Coffee and its compounds have been proposed to inhibit endometrial carcinogenesis. Studies in the Norwegian population can be especially interesting due to the high coffee consumption and increasing incidence of endometrial cancer in the country.

Methods

A total of 97 926 postmenopausal Norwegian women from the population-based prospective Norwegian Women and Cancer (NOWAC) Study, were included in the present analysis. We evaluated the general association between total coffee consumption and endometrial cancer risk as well as the possible impact of brewing method. Multivariate Cox regression analysis was used to estimate risks, and heterogeneity tests were performed to compare brewing methods.

Results

During an average of 10.9 years of follow-up, 462 incident endometrial cancer cases were identified. After multivariate adjustment, significant risk reduction was found among participants who drank ≥8 cups/day of coffee with a hazard ratio of 0.52 (95% confidence interval, CI 0.34-0.79). However, we did not observe a significant dose-response relationship. No significant heterogeneity in risk was found when comparing filtered and boiled coffee brewing methods. A reduction in endometrial cancer risk was observed in subgroup analyses among participants who drank ≥8 cups/day and had a body mass index ≥25 kg/m², and in current smokers.

Conclusions

These data suggest that in this population with high coffee consumption, endometrial cancer risk decreases in women consuming ≥8 cups/day, independent of brewing method.

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.

Intake of coffee, decaffeinated coffee, or tea does not affect risk for pancreatic cancer: results from the European Prospective Investigation into Nutrition and Cancer Study

BACKGROUND & AIMS

Few modifiable risk factors have been implicated in the etiology of pancreatic cancer. There is little evidence for the effects of caffeinated coffee, decaffeinated coffee, or tea intake on risk of pancreatic cancer. We investigated the association of total coffee, caffeinated coffee, decaffeinated coffee, and tea consumption with risk of pancreatic cancer.

METHODS

This study was conducted within the European Prospective Investigation into Nutrition and Cancer cohort, comprising male and female participants from 10 European countries. Between 1992 and 2000, there were 477,312 participants without cancer who completed a dietary questionnaire and were followed up to determine pancreatic cancer incidence. Coffee and tea intake was calibrated with a 24-hour dietary recall. Adjusted hazard ratios (HRs) were computed using multivariable Cox regression.

RESULTS

During a mean follow-up period of 11.6 y, 865 first incidences of pancreatic cancers were reported. When divided into fourths, neither total intake of coffee (HR, 1.03; 95% confidence interval [CI], 0.83-1.27; high vs low intake), decaffeinated coffee (HR, 1.12; 95% CI, 0.76-1.63; high vs low intake), nor tea were associated with risk of pancreatic cancer (HR, 1.22, 95% CI, 0.95-1.56; high vs low intake). Moderately low intake of caffeinated coffee was associated with an increased risk of pancreatic cancer (HR, 1.33; 95% CI, 1.02-1.74), compared with low intake. However, no graded dose response was observed, and the association attenuated after restriction to histologically confirmed pancreatic cancers.

CONCLUSIONS

Based on an analysis of data from the European Prospective Investigation into Nutrition and Cancer cohort, total coffee, decaffeinated coffee, and tea consumption are not related to the risk of pancreatic cancer.

Prospective study of the relationship between coffee and tea with colorectal cancer risk: the PLCO Cancer Screening Trial

Background:

Coffee and tea are commonly consumed and carry potential anticancer components that could reduce the risk of colorectal cancer; however, their relationships with colorectal cancer risk remain inconsistent.

Methods:

A prospective analysis was carried out to examine the relationships of coffee and tea intake with colorectal cancer risk in 57 398 men and women in the intervention arm of the National Cancer Institute-Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, a national screening study that limits differential detection biases. Coffee and tea intakes were assessed by food frequency questionnaire.

Results:

Six hundred and eighty-one incident colorectal cancer cases were ascertained during a median follow-up of 11.4 years. Greater coffee intake was not associated with risk of colorectal cancer (relative risk (RR)=1.08, 95% confidence interval (CI)=0.79–1.48, P_trend=0.23). Stratifying by cancer site (P_{heterogeneity}=0.48) or stage (P_{heterogeneity}=0.83) did not alter the relationship. Associations remained unchanged in subsets of participants for either caffeinated or decaffeinated coffee or when stratifying by several colorectal cancer risk factors. Similarly, greater tea intake was not associated with colorectal cancer risk overall (RR=0.77, 95% CI=0.55–1.09, P_trend=0.17) or by cancer site (P_{heterogeneity}=0.14) or stage (P_{heterogeneity}=0.60). These associations were not modified by several colorectal cancer risk factors.

Conclusion:

The findings of this study do not provide evidence to suggest that drinking coffee or tea is beneficial in protecting against colorectal cancer.

Coffee consumption and the risk of prostate cancer: the Ohsaki Cohort Study

Background:

Epidemiological evidence regarding the effect of coffee on the incidence of prostate cancer is inconsistent. We aimed to investigate coffee consumption and the risk of prostate cancer risk in a general Japanese population.

Methods:

We conducted a prospective cohort study in Ohsaki city, Japan, where 18 853 men aged 40–79 years participated in a baseline survey. Coffee consumption was assessed via a validated self-administered questionnaire. During 11 years of follow-up (from January 1 1995 to December 31, 2005), 318 incident cases of prostate cancer were detected. The Cox proportional hazards regression model was used to calculate the hazard ratios (HRs) and 95% confidence interval (CIs).

Results:

There was a significant inverse association between coffee consumption and the incidence risk of prostate cancer. Compared with those who did not drink coffee, the multivariate adjusted HRs were 0.81 (95% CI: 0.61–1.07), 0.73 (95% CI: 0.53–1.00), and 0.63 (095% CI: 0.39–1.00) for those who drank coffee occasionally, 1–2 cups per day, and ⩾3 cups per day, respectively, with a P for trend of 0.02.

Conclusion:

This prospective finding from a Japanese population adds evidence that coffee intake is inversely associated with the incidence of prostate cancer.

Coffee and caffeine intake and breast cancer risk: an updated dose-response meta-analysis of 37 published studies

OBJECTIVE

We conducted an updated meta-analysis to summarize the evidence from published studies regarding the association of coffee and caffeine intake with breast cancer risk.

METHODS

Pertinent studies were identified by a search of PubMed and by reviewing the reference lists of retrieved articles. The fixed or random effect model was used based on heterogeneity test. The dose-response relationship was assessed by restricted cubic spline model and multivariate random-effect meta-regression.

RESULTS

37 published articles, involving 59,018 breast cancer cases and 966,263 participants, were included in the meta-analysis. No significant association was found between breast cancer risk and coffee (RR=0.97, P=0.09), decaffeinated coffee (RR=0.98, P=0.55) and caffeine (RR=0.99, P=0.73), respectively. And the association was still not significant when combining coffee and caffeine (coffee/caffeine) (RR=0.97, P=0.09). However, an inverse association of coffee/caffeine with breast cancer risk was found for postmenopausal women (RR=0.94, P=0.02), and a strong and significant association of coffee with breast cancer risk was found for BRCA1 mutation carriers (RR=0.69, P<0.01). A linear dose-response relationship was found for breast cancer risk with coffee and caffeine, and the risk of breast cancer decreased by 2% (P=0.05) for every 2 cups/day increment in coffee intake, and 1% (P=0.52) for every 200mg/day increment in caffeine intake, respectively.

CONCLUSIONS

Findings from this meta-analysis suggested that coffee/caffeine might be weakly associated with breast cancer risk for postmenopausal women, and the association for BRCA1 mutation carriers deserves further investigation.

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.

Caffeinated and decaffeinated coffee and tea intakes and risk of colorectal cancer in a large prospective study

BACKGROUND

Coffee and tea are widely consumed globally and are rich sources of potential chemopreventive compounds. Epidemiologic data for coffee and tea intakes in relation to colorectal cancer remain unclear. Despite differences in gut physiology, few studies have conducted investigations by anatomic subsites.

OBJECTIVE

We evaluated coffee and tea intakes (caffeinated and decaffeinated) in relation to colon (proximal and distal) and rectal cancers.

DESIGN

The NIH-AARP Diet and Health Study included 489,706 men and women who completed a baseline (1995-1996) self-administered questionnaire of demographics, diet, and lifestyle. Over a median of 10.5 y of follow-up, we identified 2863 proximal colon, 1993 distal colon, and 1874 rectal cancers. Multivariable HRs and 95% CIs were estimated by using Cox regression.

RESULTS

Approximately 16% of participants drank ≥4 cups coffee/d. Compared with nondrinkers, drinkers of 4-5 cups coffee/d (HR: 0.85; 95% CI: 0.75, 0.96) and ≥6 cups coffee/d (HR: 0.74; 95% CI: 0.61, 0.89; P-trend < 0.001) had a lower risk of colon cancer, particularly of proximal tumors (HR for ≥6 cups/d: 0.62; 95% CI: 0.49, 0.81; P-trend < 0.0001). Results were similar to those overall for drinkers of predominantly caffeinated coffee. Although individual HRs were not significant, there was a significant P-trend for both colon and rectal cancers for people who drank predominantly decaffeinated coffee. No associations were observed for tea.

CONCLUSIONS

In this large US cohort, coffee was inversely associated with colon cancer, particularly proximal tumors. Additional investigations of coffee intake and its components in the prevention of colorectal cancer by subsites are warranted. The NIH-AARP Diet and Health Study was registered at clinicaltrials.gov as NCT00340015.

Coffee and black tea consumption and breast cancer mortality in a cohort of Swedish women

Background:

Coffee and black tea contain a mixture of compounds that have the potential to influence breast cancer risk and survival. However, epidemiologic data on the relation between coffee and black tea consumption and breast cancer survival are sparse.

Methods:

We investigated the association between coffee and black tea consumption and survival among 3243 women with invasive breast cancer in the Swedish Mammography Cohort. Intake was estimated using a food frequency questionnaire. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs).

Results:

From 1987 to 2010 there were 394 breast cancer-specific deaths and 973 total deaths. Coffee and black tea were not associated with breast cancer-specific or overall mortality. Women consuming 4+ cups of coffee per day had a covariate and clinical characteristics-adjusted HR (95% CI) of death from breast cancer of 1.14 (0.71–1.83; p_trend=0.81) compared with those consuming <1 cup per day. Women consuming 2+ cups of black tea per day had a covariate and clinical characteristics-adjusted HR (95% CI) of death from breast cancer of 1.02 (0.67–1.55; p_trend=0.94) compared with non-tea drinkers. Caffeine was also not associated with breast cancer-specific (HR for top to bottom quartile=1.06; 95% CI=0.79–1.44; p_trend=0.71) or overall mortality.

Conclusion:

Our findings suggest that coffee, black tea, and caffeine consumption before breast cancer diagnosis do not influence breast cancer-specific and overall survival.

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.

Associations among 25-year trends in diet, cholesterol and BMI from 140,000 observations in men and women in Northern Sweden

BACKGROUND

In the 1970s, men in northern Sweden had among the highest prevalences of cardiovascular diseases (CVD) worldwide. An intervention program combining population- and individual-oriented activities was initiated in 1985. Concurrently, collection of information on medical risk factors, lifestyle and anthropometry started. Today, these data make up one of the largest databases in the world on diet intake in a population-based sample, both in terms of sample size and follow-up period. The study examines trends in food and nutrient intake, serum cholesterol and body mass index (BMI) from 1986 to 2010 in northern Sweden.

METHODS

Cross-sectional information on self-reported food and nutrient intake and measured body weight, height, and serum cholesterol were compiled for over 140,000 observations. Trends and trend breaks over the 25-year period were evaluated for energy-providing nutrients, foods contributing to fat intake, serum cholesterol and BMI.

RESULTS

Reported intake of fat exhibited two significant trend breaks in both sexes: a decrease between 1986 and 1992 and an increase from 2002 (women) or 2004 (men). A reverse trend was noted for carbohydrates, whereas protein intake remained unchanged during the 25-year period. Significant trend breaks in intake of foods contributing to total fat intake were seen. Reported intake of wine increased sharply for both sexes (more so for women) and export beer increased for men. BMI increased continuously for both sexes, whereas serum cholesterol levels decreased during 1986 - 2004, remained unchanged until 2007 and then began to rise. The increase in serum cholesterol coincided with the increase in fat intake, especially with intake of saturated fat and fats for spreading on bread and cooking.

CONCLUSIONS

Men and women in northern Sweden decreased their reported fat intake in the first 7 years (1986-1992) of an intervention program. After 2004 fat intake increased sharply for both genders, which coincided with introduction of a positive media support for low carbohydrate-high-fat (LCHF) diet. The decrease and following increase in cholesterol levels occurred simultaneously with the time trends in food selection, whereas a constant increase in BMI remained unaltered. These changes in risk factors may have important effects on primary and secondary prevention of cardiovascular disease (CVD).

A traditional Sami diet score as a determinant of mortality in a general northern Swedish population

OBJECTIVES

To examine the relationship between "traditional Sami" dietary pattern and mortality in a general northern Swedish population.

STUDY DESIGN

Population-based cohort study.

METHODS

We examined 77,319 subjects from the Västerbotten Intervention Program (VIP) cohort. A traditional Sami diet score was constructed by adding 1 point for intake above the median level of red meat, fatty fish, total fat, berries and boiled coffee, and 1 point for intake below the median of vegetables, bread and fibre. Hazard ratios (HR) for mortality were calculated by Cox regression.

RESULTS

Increasing traditional Sami diet scores were associated with slightly elevated all-cause mortality in men [Multivariate HR per 1-point increase in score 1.04 (95% CI 1.01-1.07), p=0.018], but not for women [Multivariate HR 1.03 (95% CI 0.99-1.07), p=0.130]. This increased risk was approximately equally attributable to cardiovascular disease and cancer, though somewhat more apparent for cardiovascular disease mortality in men free from diabetes, hypertension and obesity at baseline [Multivariate HR 1.10 (95% CI 1.01-1.20), p=0.023].

CONCLUSIONS

A weak increased all-cause mortality was observed in men with higher traditional Sami diet scores. However, due to the complexity in defining a "traditional Sami" diet, and the limitations of our questionnaire for this purpose, the study should be considered exploratory, a first attempt to relate a "traditional Sami" dietary pattern to health endpoints. Further investigation of cohorts with more detailed information on dietary and lifestyle items relevant for traditional Sami culture is warranted.

Coffee, tea, soda, and caffeine intake in relation to risk of adult glioma in the NIH-AARP Diet and Health Study

PURPOSE

We utilized the large, prospective NIH-AARP Diet and Health Study to further explore the hypothesis, suggested by two recent prospective cohort studies, that increased intake of coffee, tea, soda, and/or caffeine is associated with reduced adult glioma risk.

METHODS

At baseline in 1995-1996, dietary intake, including coffee, tea, and soda, was assessed with a food frequency questionnaire. We used Cox proportional hazards models to calculate adjusted hazard ratios (HR) and 95 % confidence intervals (CI) for glioma risk in relation to beverage intake.

RESULTS

During follow-up of 545,771 participants through 2006, 904 participants were diagnosed with glioma. We found no trends of decreasing glioma risk with increasing intake of specific beverages or total caffeine. HR patterns for consumption of the caffeinated versus decaffeinated form of each beverage were inconsistent with a specific caffeine effect. HR patterns of reduced glioma risk for most categories of beverage intake greater than "none" prompted a post hoc analysis that revealed borderline-significant inverse associations for any versus no intake of tea (HR = 0.84; 95 % CI, 0.69-1.03), total coffee plus tea (HR = 0.70; 95 % CI, 0.48-1.03), and soda (HR = 0.82; 95 % CI, 0.67-1.01).

CONCLUSIONS

The borderline-significant inverse associations could be explained by a threshold effect in which any beverage intake above a low level confers a beneficial effect, most likely due to beverage constituents other than caffeine. They could also be explained by non-drinkers of these beverages sharing unknown extraneous characteristics associated with increased glioma risk, or by chance.

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.

Functional roles of melatonin in plants, and perspectives in nutritional and agricultural science

The presence of melatonin in plants is universal. Evidence has confirmed that a major portion of the melatonin is synthesized by plants themselves even though a homologue of the classic arylalkylamine N-acetyltransferase (AANAT) has not been identified as yet in plants. Thus, the serotonin N-acetylating enzyme in plants may differ greatly from the animal AANAT with regard to sequence and structure. This would imply multiple evolutionary origins of enzymes with these catalytic properties. A primary function of melatonin in plants is to serve as the first line of defence against internal and environmental oxidative stressors. The much higher melatonin levels in plants compared with those found in animals are thought to be a compensatory response by plants which lack means of mobility, unlike animals, as a means of coping with harsh environments. Importantly, remarkably high melatonin concentrations have been measured in popular beverages (coffee, tea, wine, and beer) and crops (corn, rice, wheat, barley, and oats). Billions of people worldwide consume these products daily. The beneficial effects of melatonin on human health derived from the consumption of these products must be considered. Evidence also indicates that melatonin has an ability to increase the production of crops. The mechanisms may involve the roles of melatonin in preservation of chlorophyll, promotion of photosynthesis, and stimulation of root development. Transgenic plants with enhanced melatonin content could probably lead to breakthroughs to increase crop production in agriculture and to improve the general health of humans.

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.

Coffee intake and breast cancer risk in the NIH-AARP diet and health study cohort

There are several biologic mechanisms whereby coffee might reduce breast cancer risk. Caffeine and caffeic acid, major coffee constituents, have been shown to suppress mammary tumor formation in animal models and to inhibit DNA methylation in human breast cancer cells, respectively. Coffee may also reduce risk through decreasing inflammation and influencing estrogen metabolism. However, epidemiologic studies have been inconsistent and few studies have examined the association by estrogen and progesterone receptor (ER/PR) status. We evaluated coffee intake for its effect on incident breast cancer in the National Institutes of Health-AARP Diet and Health Study cohort, which included 198,404 women aged 50-71 with no history of cancer, who in 1995-1996 completed a questionnaire capturing usual coffee intake over the past year. State cancer registry and mortality index linkage identified 9,915 primary incident breast carcinomas through December 2006; available information on hormone receptor (HR) status identified 2,051 ER+/PR+ and 453 ER-/PR- cancers. In multivariable proportional hazards models, coffee intake was not associated with breast cancer risk (p-value for trend = 0.38; relative risk = 0.98, 95% confidence interval: 0.91-1.07, for four or more cups per day as compared to women who never drank coffee), and results did not vary by body mass index or history of benign breast biopsy (p-value for interaction > 0.10). We found no evidence of a relationship with either caffeinated or decaffeinated coffee. Null findings persisted for risk of both HR-positive and -negative breast cancers. These findings from a large prospective cohort do not support a role of coffee intake in breast carcinogenesis.

Coffee consumption modifies risk of estrogen-receptor negative breast cancer

Introduction

Breast cancer is a complex disease and may be sub-divided into hormone-responsive (estrogen receptor (ER) positive) and non-hormone-responsive subtypes (ER-negative). Some evidence suggests that heterogeneity exists in the associations between coffee consumption and breast cancer risk, according to different estrogen receptor subtypes. We assessed the association between coffee consumption and postmenopausal breast cancer risk in a large population-based study (2,818 cases and 3,111 controls), overall, and stratified by ER tumour subtypes.

Methods

Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated using the multivariate logistic regression models fitted to examine breast cancer risk in a stratified case-control analysis. Heterogeneity among ER subtypes was evaluated in a case-only analysis, by fitting binary logistic regression models, treating ER status as a dependent variable, with coffee consumption included as a covariate.

Results

In the Swedish study, coffee consumption was associated with a modest decrease in overall breast cancer risk in the age-adjusted model (OR_{> 5 cups/day} compared to OR_{≤ 1 cup/day}: 0.80, 95% CI: 0.64, 0.99, P trend = 0.028). In the stratified case-control analyses, a significant reduction in the risk of ER-negative breast cancer was observed in heavy coffee drinkers (OR_{> 5 cups/day} compared to OR_{≤ 1 cup/day} : 0.43, 95% CI: 0.25, 0.72, P trend = 0.0003) in a multivariate-adjusted model. The breast cancer risk reduction associated with higher coffee consumption was significantly higher for ER-negative compared to ER-positive tumours (P heterogeneity (age-adjusted) = 0.004).

Conclusions

A high daily intake of coffee was found to be associated with a statistically significant decrease in ER-negative breast cancer among postmenopausal women.

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.