Coffee consumption and risk of endometrial cancer: a prospective study in Japan

Coffee has been proposed to decrease the circulating insulin and estrogen levels, which are related to the development of endometrial cancer. However, few studies have prospectively assessed the association between coffee consumption and endometrial cancer. We conducted a population-based prospective cohort study in 53,724 Japanese women aged 40-69 years with no history of cancer at baseline in 1990-1994. We used Cox proportional hazards regression analysis to estimate the hazard ratio (HR) and 95% confidence interval (CI) of endometrial cancer incidence in relation to coffee consumption. All reported p values are 2-tailed. During the 15-year follow-up period, we documented 117 cases of endometrial cancer. Coffee consumption was significantly associated with a decreased risk of endometrial cancer. After adjustment for age, study area, body mass index, menopausal status, age at menopause for postmenopausal women, parity, use of exogenous female hormones, smoking status and by consumption of green vegetables, beef, pork and green tea, the multivariate HRs (95% CI) of endometrial cancer in women who drank coffee /=3 cups/day were 1.00, 0.97 (0.56-1.68), 0.61 (0.39-0.97) and 0.38 (0.16-0.91), respectively (p for trend = 0.007). In contrast, green tea consumption was not significantly associated with a reduced risk of endometrial cancer (p for trend = 0.22). The inverse association between coffee consumption and risk of endometrial cancer was consistently observed in subgroup analyses stratified by potential confounders. Coffee consumption may be associated with a decreased risk of endometrial cancer.     

A prospective investigation of coffee drinking and endometrial cancer incidence

Coffee drinking may be associated with reduced risk of endometrial cancer; however, prospective data are limited. Further, it is not clear whether any association between coffee and endometrial cancer differs according to coffee caffeine content. The association of coffee drinking with incidence of endometrial cancer was evaluated among 226,732 women, aged 50-71, enrolled in the NIH-AARP Diet and Health Study who completed a baseline epidemiologic questionnaire. Following a mean 9.3 years of follow-up, data were available for 1,486 incident endometrial cancer cases. Cox proportional hazards models were used to estimate associations of coffee with endometrial cancer incidence. Sub-group analyses were performed according to smoking status, hormone therapy use (HT) and body habitus. Coffee drinking was inversely related to incidence of endometrial cancer (hazard ratio [HR] comparing drinking of >3 cups/day versus no cups = 0.64, 95% CI, 0.51-0.80; P(trend) = 0.0004). The association of coffee with endometrial cancer risk was apparent for consumption of both regular (HR per cup = 0.90, 95% CI, 0.86-0.95) and decaffeinated coffee (HR per cup = 0.93, 95% CI, 0.87-0.99). The relation of coffee with endometrial cancer incidence varied significantly by HT use (P(interaction) = 0.03) with an association only apparent among HT-never users (HR comparing drinking >3 cups/day versus no cups = 0.54, 95% CI, 0.41-0.72; P(trend) = 0.0005). Endometrial cancer incidence appears to be reduced among women that habitually drink coffee, an association that does not differ according to caffeine content.     

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. © 2009 UICC     

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 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 breast cancer risk among BRCA1 and BRCA2 mutation carriers

Although there are several plausible biologic mechanisms whereby coffee consumption might influence the risk of breast cancer, epidemiologic evidence is limited. We assessed the association between coffee consumption and breast cancer risk among high-risk women who carry BRCA mutations. We performed a matched case-control analysis on 1,690 women with a BRCA1 or BRCA2 mutation from 40 centers in 4 countries. Average lifetime coffee consumption was estimated via a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for potential confounders, the ORs for breast cancer in BRCA carriers who habitually drank 0, 1-3, 4-5 and 6 or more cups of coffee were 1.00, 0.90 (95% CI 0.72-1.12), 0.75 (95% CI 0.47-1.19) and 0.31 (95% CI 0.13-0.71; p-trend = 0.02). The effect was limited to the consumption of caffeinated coffee. These results suggest that among women with BRCA gene mutation, coffee consumption is unlikely to be harmful and that high levels of consumption may in fact be related to reduced breast cancer risk.     

Processed meat consumption, dietary nitrosamines and stomach cancer risk in a cohort of Swedish women

Processed meat consumption has been associated with an increased risk of stomach cancer in some epidemiological studies (mainly case-control). Nitrosamines may be responsible for this association, but few studies have directly examined nitrosamine intake in relation to stomach cancer risk. We prospectively investigated the associations between intakes of processed meat, other meats and N-nitrosodimethylamine (the most frequently occurring nitrosamine in foods) with risk of stomach cancer among 61,433 women who were enrolled in the population-based Swedish Mammography Cohort. Information on diet was collected at baseline (between 1987 and 1990) and updated in 1997. During 18 years of follow-up, 156 incident cases of stomach cancer were ascertained. High consumption of processed meat, but not of other meats (i.e., red meat, fish and poultry), was associated with a statistically significant increased risk of stomach cancer. After adjustment for potential confounders, the hazard ratios for the highest compared with the lowest category of intake were 1.66 (95% CI = 1.13-2.45) for all processed meats, 1.55 (95% CI = 1.00-2.41) for bacon or side pork, 1.50 (95% CI = 0.93-2.41) for sausage or hotdogs and 1.48 (95% CI= 0.99-2.22) for ham or salami. Stomach cancer risk was 2-fold higher among women in the top quintile of N-nitrosodimethylamine intake when compared with those in the bottom quintile (hazard ratio = 1.96; 95% CI = 1.08-3.58). Our findings suggest that high consumption of processed meat may increase the risk of stomach cancer. Dietary nitrosamines might be responsible for the positive association.     

Coffee consumption and the risk of colorectal cancer: a prospective cohort study in Japan

An inverse association between coffee consumption and the risk of colorectal cancer has been reported in several case-control studies, but results from prospective cohort studies have been inconclusive. We conducted a prospective cohort study among a Japanese population to clarify the association between coffee consumption and the risk of colorectal cancer incidence. We used data from the Miyagi Cohort Study for this analysis. Usable self-administered questionnaires about coffee consumption were returned from 22,836 men and 24,769 women, aged 40-64 years, with no previous history of cancer. We used the Cox proportional-hazard regression model to estimate hazard ratios and 95% confidence intervals. During 11.6 years of follow-up (425,303 person-years), we identified 457 cases of colorectal cancer. Coffee consumption was not associated with the incidence of colorectal, colon or rectal cancer. The multivariate-adjusted hazard ratio (95% confidence interval) of colorectal cancer incidence for 3 or more cups of coffee per day as compared with no consumption was 0.95 (0.65-1.39) for men and women (p for trend = 0.55), 0.91 (0.56-1.46) for men (p for trend = 0.53) and 1.16 (0.60-2.23) for women (p for trend = 0.996). Coffee consumption was also not associated with incidence of either proximal or distal colon cancer. We conclude that coffee consumption is not associated with the incidence risk of colorectal cancer in the general population in Japan.     

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.     

Alcohol consumption and risk of renal cell carcinoma: a prospective study of Swedish women

Previous literature, although not consistent, suggests that moderate alcohol consumption might be associated with decreased risk of renal cell carcinoma (RCC) in women. Thus, we examined the association between alcohol intake and the incidence of RCC by analyzing data from the Swedish Mammography Cohort, a population-based prospective cohort of 59,237 women, aged 40-76 years, who, at baseline in 1987-1990, were cancer free and had completed a food-frequency questionnaire including questions about alcohol consumption. Through June 30, 2004, 132 incident cases of RCC were diagnosed. We used the Cox proportional hazards model to estimate age and body mass index (BMI) adjusted rate ratios (RRs) and their 95% confidence intervals (CIs). Women who consumed >4.3 grams per day of alcohol (ethanol) had nonsignificantly lower risk of RCC than did women who consumed <2.5 g/d (RR = 0.71, 95% CI 0.42-1.19); among women > or = 55 years of age at entry into the cohort, corresponding risk estimates were RR = 0.33, 95% CI 0.10-1.05, p for trend = 0.04 and among women with BMI >25 kg/m2, RR = 0.30, 95% CI 0.09-0.97, p for trend = 0.04. Consistent with these findings, women who drank 1 or more servings of total alcoholic beverages per week had lower RCC risk than did women who drank less (RR = 0.62, 95% CI 0.41-0.94); the corresponding estimate for women > or = 55 years of age was RR = 0.44, 95% CI 0.22-0.88. Results from our prospective cohort study of middle-aged and elderly women indicate that moderate alcohol consumption may be associated with decreased risk of RCC.     

Coffee and caffeine intake and the risk of ovarian cancer: the Iowa Women’s Health Study

Laboratory data suggest that caffeine or some components of coffee may cause DNA mutations and inhibit tumor suppressor mechanisms, leading to neoplastic growth. However, coffee consumption has not been clearly implicated in the etiology of human postmenopausal ovarian cancer. This study evaluated the relationship of coffee and caffeine intake with risk of epithelial ovarian cancer in a prospective cohort study of 29,060 postmenopausal women. The participants completed a mailed questionnaire that assessed diet and health history and were followed for ovarian cancer incidence from 1986 to 2004. Age-adjusted and multivariate-adjusted hazard ratios were calculated for four exposure variables: caffeinated coffee, decaffeinated coffee, total coffee, and total caffeine to assess whether or not coffee or caffeine influences the risk of ovarian cancer. An increased risk was observed in the multivariate model for women who reported drinking five or more cups/day of caffeinated coffee compared to women who reported drinking none (HR = 1.81, 95% CI: 1.10–2.95). Decaffeinated coffee, total coffee, and caffeine were not statistically significantly associated with ovarian cancer incidence. Our results suggest that a component of coffee other than caffeine, or in combination with caffeine, may be associated with increased risk of ovarian cancer in postmenopausal women who drink five or more cups of coffee a day.     

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 and the risk of primary liver cancer: pooled analysis of two prospective studies in Japan

Although case-control studies suggested that coffee consumption is associated with a decreased risk of liver cancer, no prospective cohort study has been carried out. To examine the association between coffee consumption and the risk of liver cancer, we conducted a pooled analysis of data available from 2 cohort studies in Japan. A self-administered questionnaire about the frequency of coffee consumption and other health habits was distributed to 22,404 subjects (10,588 men and 11,816 women) in Cohort 1 and 38,703 subjects (18,869 men and 19,834 women) in Cohort 2, aged 40 years or more, with no previous history of cancer. We identified 70 and 47 cases of liver cancer among the subjects in Cohort 1 (9 years of follow-up with 170,640 person-years) and Cohort 2 (7 years of follow-up with 284,948 person-years), respectively. We used Cox proportional hazards regression analysis to estimate the relative risk (RR) and 95% confidence interval (CI) of liver cancer incidence. After adjustment for potential confounders, the pooled RR (95% CI) of drinking coffee never, occasionally and 1 or more cups/day were 1.00 (Reference), 0.71 (0.46-1.09) and 0.58 (0.36-0.96), respectively (p for trend = 0.024). In the subgroup of subjects with a history of liver disease, we found a significant inverse association between coffee consumption and the risk of liver cancer. Our findings support the hypothesis that coffee consumption decreases the risk of liver cancer. Further studies to investigate the role of coffee in prevention of liver cancer among the high-risk population are needed.     

Coffee and tea consumption and cancers of the bladder, colon and rectum.

Coffee has been observed to be associated weakly or not at all with bladder cancer risk, inversely with colon cancer risk, and inconsistently with rectal cancer risk. The association between these cancers and consumption of coffee and tea was examined in a single case-control study conducted in Ontario, Canada from 1992 to 1994. A questionnaire was filled out by 927 bladder cancer cases, 991 colon cancer cases, 875 rectal cancer cases, and 2118 population controls. Although bladder cancer risk was not associated with coffee or tea, risk estimates associated with coffee among subjects who had never smoked were non-significantly increased. Colon cancer risk was inversely associated with coffee. Relative to those drinking less than 1 cup of coffee per day, the odds ratios (OR) for those drinking 1-2 cups was 0.9 (95% CI 0.8-1.1), for those drinking 3-4 cups was 0.8 (95% CI 0.7-1.0), and for those drinking 5 or more cups was 0.7 (95% CI 0.5-0.9); these ORs decreased linearly (P = 0.008). The reduced risk estimates were more pronounced with cancer of the proximal colon than the distal colon. Rectal cancer risk was not associated with either coffee or tea. Coffee consumption was observed to have a different relationship for each of the cancer sites and tea consumption was not related to any cancer site.     

A prospective study of tea and coffee intake and risk of glioma

Tea and coffee have antioxidant and neuroprotective effects. Observational studies suggest that tea and coffee intake may reduce cancer risk, but data on glioma risk are inconclusive. We evaluated the association between tea, coffee and caffeine intake and glioma risk in the female Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII) and the male Health Professionals Follow-Up Study (HPFS). Cumulative intake was derived from validated quadrennial food frequency questionnaires. Glioma cases were confirmed by medical record review. Multivariable-adjusted hazard ratios of glioma by beverage intake category were estimated using Cox proportional hazards models. We documented 554 incident cases of glioma (256 in NHS, 87 in NHSII and 211 in HPFS). Compared to <1 cup/week, higher tea consumption was borderline inversely associated with glioma risk in pooled cohorts (hazard ratio [HR] = 0.73, 95% confidence interval [CI]: 0.49–1.10 for >2 cups/day, p-trend = 0.05), but not in women (HR = 0.74, 95% CI: 0.47–1.18 for >2 cups/day, p-trend = 0.11) or men (HR = 0.70, 95% CI: 0.30–1.60 for >2 cups/day, p-trend = 0.30) separately. Overall, we observed no significant associations between caffeinated, decaffeinated or total coffee intake and glioma risk. There were no material differences in the results with baseline values, 8-year lagged responses, or when limited to glioblastoma (n = 362). In three large prospective cohort studies, tea intake was borderline inversely associated with glioma risk. No significant associations were observed for coffee intake and glioma risk. These results merit further exploration in prospective studies.     

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 consumption and risk of colorectal cancer in a population-based prospective cohort of Japanese men and women

We prospectively examined the association between coffee consumption and the risk of developing colorectal cancer in a large population-based cohort study (the JPHC Study) of Japanese men and women. Data were analyzed from a population-based cohort of 96,162 subjects (46,023 men and 50,139 women). A total of 1,163 incident colorectal cancers were identified during the follow-up period, including 763 cases of colon cancer and 400 of rectal cancer. We observed a significant inverse association between coffee consumption and the risk of developing invasive colon cancer among women. Compared with those who almost never consumed coffee, women who regularly consumed 3 or more cups of coffee per day had a RR of 0.44 (95% CI = 0.19-1.04; p for trend = 0.04) after adjustment for potential confounding factors. However, no significant association was found for rectal cancer in women. In men, no significant decrease was observed in any colorectal cancer site. Further, additional analyses on the association of green tea consumption with colorectal cancer risk found no significant association in men or women. These findings suggest that coffee consumption may lower the risk of colon cancer among Japanese women.     

Intakes of coffee, tea, milk, soda and juice and renal cell cancer in a pooled analysis of 13 prospective studies

Specific beverage intake may be associated with the risk of renal cell cancer through a diluting effect of carcinogens, alterations of hormone levels, or other changes in the renal tubular environment, but few prospective studies have examined these associations. We evaluated the associations between coffee, tea, milk, soda and fruit and vegetable juice intakes and renal cell cancer risk in a pooled analysis of 13 prospective studies (530,469 women and 244,483 men). Participants completed a validated food-frequency questionnaire at baseline. Using the primary data, the study-specific relative risks (RRs) were calculated and then pooled using a random effects model. A total of 1,478 incident renal cell cancer cases were identified during a follow-up of 7-20 years across studies. Coffee consumption was associated with a modestly lower risk of renal cell cancer (pooled multivariate RR for 3 or more 8 oz (237 ml) cups/day versus less than one 8 oz (237 ml) cup/day = 0.84; 95% CI = 0.67-1.05; p value, test for trend = 0.22). Tea consumption was also inversely associated with renal cell cancer risk (pooled multivariate RR for 1 or more 8 oz (237 ml) cups/day versus nondrinkers = 0.85; 95% CI = 0.71-1.02; pvalue, test for trend = 0.04). No clear associations were observed for milk, soda or juice. Our findings provide strong evidence that neither coffee nor tea consumption increases renal cell cancer risk. Instead, greater consumption of coffee and tea may be associated with a lower risk of renal cell cancer. (c) 2007 Wiley-Liss, Inc.     

Are Coffee, Tea, and Total Fluid Consumption associated with Bladder Cancer Risk? Results from the Netherlands Cohort Study

Objectives: Coffee, tea, and fluid consumption have been thought to influence bladder cancer incidence. In a large prospective study, these associations were investigated. Methods: In 1986, cohort members (55–69 years) completed a questionnaire on cancer risk factors. Follow-up was established by linkage to cancer registries until 1992. The multivariable case–cohort analysis was based on 569 bladder cancer cases and 3123 subcohort members. Results: The incidence rate ratios (RR) for men consuming <2 cups of coffee/day was 0.89 (95% CI 0.51–1.5) using the median consumption category (4–<5 cups/day) as reference. This RR increased to 1.3 (95% CI 0.94–1.9) for men consuming 7 cups/day, although no clear dose–response association was found. The RRs decreased from 1.2 (95% CI 0.56–2.7) for women consuming <2 cups of coffee/day to 0.36 (95% CI 0.18–0.72) for women consuming 5 cups/day compared to the median consumption category (3–<4 cups/day). Men and women who abstained from drinking tea had a RR of 1.3 (95% CI 0.97–1.8) compared to those consuming 2–<3 cups of tea per day (median consumption category). The RR for men and women comparing highest to lowest quintile of total fluid consumption was 0.87 (95% CI 0.63–1.2). Conclusion: The data suggest a possible positive association between coffee consumption and bladder cancer risk in men and a probable inverse association in women. Tea consumption was inversely associated with bladder cancer. Total fluid consumption did not appear to be associated with bladder cancer.     

Coffee Consumption and Pancreatic Cancer Risk: A Meta-Epidemiological Study of Population-based Cohort Studies

Objective: Previous systematic reviews evaluating the association between coffee consumption and pancreatic cancer showed inconsistent results. The aim was to conduct a meta-epidemiological study to explore further the association between coffee consumption and the incidence of pancreatic cancer. Methods: The selection criteria were defined as a population-based prospective cohort study reporting adjusted relative risk (RR) and their 95% confidence interval (95%CI) of pancreatic cancer occurrence according to coffee consumption. Adjusted RR for the highest versus the lowest level of coffee consumption in each study was extracted. A fixed-effect model was applied to calculate a summary RR (sRR) and its 95%CI. Two-stage random-effects dose-response meta-analysis (DRMA) was performed to estimate the incidence risk per unit dose (cup per day). Results: Twelve cohort studies were selected for meta-analysis. The total number of cohort participants was 3,230,053, and pancreatic cancer incidents were 10,587. The sRR of pancreatic cancer risk for the highest versus the lowest level of coffee consumption indicated no statistical significance (sRR=0.98, 95% CI: 0.88-1.10; I-squared=0.0%). Two-stage random-effect DRMA showed the non-linear relationship between the amount of coffee consumption and pancreatic cancer risk. And the RR for an increment of one cup per day of coffee consumption was 0.97 (95%CI: 0.91-1.04, P=0.42), without statistically significant. Conclusion: There was no association between coffee consumption habits and pancreatic cancer risk. And there was no statistical significance in the dose-response relationship between the amount of coffee consumption and pancreatic cancer risk. Finding the turning point would be important because it can be critical information for the prevention of pancreatic cancer.