Coffee and tea consumption and mortality from all causes, cardiovascular disease and cancer: a pooled analysis of prospective studies from the Asia Cohort Consortium.

BACKGROUND: Accumulating evidence suggests that consuming coffee may lower the risk of death, but evidence regarding tea consumption in Asians is limited. We examined the association between coffee and tea consumption and mortality in Asian populations. METHODS: We used data from 12 prospective cohort studies including 248 050 men and 280 454 women from the Asia Cohort Consortium conducted in China, Japan, Korea and Singapore. We estimated the study-specific association of coffee, green tea and black tea consumption with mortality using Cox proportional-hazards regression models and the pooled study-specific hazard ratios (HRs) using a random-effects model. RESULTS: In total, 94 744 deaths were identified during the follow-up, which ranged from an average of 6.5 to 22.7 years. Compared with coffee non-drinkers, men and women who drank at least five cups of coffee per day had a 24% [95% confidence interval (CI) 17%, 29%] and a 28% (95% CI 19%, 37%) lower risk of all-cause mortality, respectively. Similarly, we found inverse associations for coffee consumption with cardiovascular disease (CVD)-specific and cancer-specific mortality among both men and women. Green tea consumption was associated with lower risk of mortality from all causes, CVD and other causes but not from cancer. The association of drinking green tea with CVD-specific mortality was particularly strong, with HRs (95% CIs) of 0.79 (0.68, 0.91) for men and 0.78 (0.68, 0.90) for women who drank at least five cups per day of green tea compared with non-drinkers. The association between black tea consumption and mortality was weak, with no clear trends noted across the categories of consumption. CONCLUSIONS: In Asian populations, coffee consumption is associated with a lower risk of death overall and with lower risks of death from CVD and cancer. Green tea consumption is associated with lower risks of death from all causes and CVD.

Coffee, green tea and liver cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population.

BACKGROUND: Coffee and green tea, two popular drinks in the Japanese, have recently drawn much attention as potential protective factors against the occurrence of liver cancer. METHODS: We systematically reviewed epidemiologic studies on coffee, green tea and liver cancer among Japanese populations. Original data were obtained by searching the MEDLINE (PubMed) and Ichushi databases, complemented with manual searches. The evaluation was performed in terms of the magnitude of association in each study and the strength of evidence ('convincing', 'probable', 'possible', or 'insufficient'), together with biological plausibility. RESULTS: We identified four cohort and four case-control studies on coffee and liver cancer and six cohort and one case-control studies on green tea and liver cancer. All cohort and case-control studies on coffee reported a weak to strong inverse association, with a summary relative risk (RR) for one cup increase being 0.72 (95% confidence interval [CI] 0.66-0.79). Conversely, all studies but two cohort studies on green tea reported no association, with a corresponding summary RR of 0.99 (95% CI 0.97-1.01, P = 0.37). CONCLUSION: Coffee drinking 'probably' decreases the risk of primary liver cancer among the Japanese population whereas the evidence on an association between green tea and liver cancer is 'insufficient' in this population.

Green tea consumption and mortality in Japanese men and women: a pooled analysis of eight population-based cohort studies in Japan.

The aim of our study was to assess the association between green tea consumption and all-cause and cause-specific mortality in a pooled analysis of eight Japanese population-based cohort studies. Pooled hazard ratios (HR) and 95% confidence intervals (CI), derived from random effects models, were used to evaluate the associations between green tea consumption, based on self-report at baseline, and risk of all-cause and cause-specific mortality. During a mean follow-up of 17.3 years, among 313,381 persons, 52,943 deaths occurred. Compared with individuals who consumed < 1 cup/day, those in the highest consumption category (≥ 5 cups/day) had a decreased risk of all-cause mortality [the multivariate-adjusted HR was 0.90 (95% CI 0.87-0.94) for men and 0.82 (0.74-0.90) for women]. A similar inverse association was observed for heart disease mortality [HR 0.82 (0.75-0.90) for men, and 0.75 (0.68-0.84) for women], and cerebrovascular disease mortality [HR 0.76 (0.68-0.85) for men, and 0.78 (0.68-0.89) for women]. Among women, green tea consumption was associated with decreased risk of total cancer mortality: 0.89 (0.83-0.96) for the 1-2 cups/day category and 0.91 (0.85-0.98) for the 3-4 cups/day category. Results for respiratory disease mortality were [HR 0.75 (0.61-0.94)] among 3-4 cup daily consumers and [HR 0.66 (0.55-0.79)] for ≥ 5 cups/day. Higher consumption of green tea is associated with lower risk for all-cause mortality in Japanese, especially for heart and cerebrovascular disease. Moderate consumption decreased the risk of total cancer and respiratory disease mortality in women.

Coffee consumption and mortality in Japanese men and women: A pooled analysis of eight population-based cohort studies in Japan (Japan Cohort Consortium).

Coffee consumption is increasing globally. We aimed to assess the effect of coffee consumption on the risk of all-cause and cause-specific mortality in a pooled analysis of eight population-based cohort studies in Japan (Japan Cohort Consortium). Data came from eight Japanese cohort studies (144,750 men and 168,631 women). During a mean follow-up time of 17 years, 52,943 deaths occurred. More specifically, 19,495 cancer deaths, 7321 deaths due to heart disease, 6387 cerebrovascular, 3490 respiratory disease and 3382 injuries and accidents. A random effects model was applied to obtain pooled hazard ratios (HRs) and 95% confidence intervals (95%CIs). In both sexes, coffee consumption up to 5 cups/day was overall protective in relation to all-cause mortality, with the association attenuating in the highest category of coffee consumption (≥5 cups/day). In men, a similar inverse association was observed for major causes of mortality except cancer. In women, coffee consumption decreased the risk for mortality due to heart disease in the 1-2 cups/day category, but increased the risk in the ≥5 cups/day category. Coffee consumption was not associated with cancer in both sexes. Results were similar among male current smokers and female never-smokers. Based on available data, this pooled analysis suggests that coffee consumption under five cups per day may be beneficial for reducing the risk of mortality due to major causes.

Coffee Consumption and All-Cause and Cardiovascular Mortality　- Three-Prefecture Cohort in Japan.

BACKGROUND: Coffee, which contains various bioactive compounds, is one of the most popular beverages. Further accumulation of evidence is needed, however, to confirm whether coffee consumption would be effective in preventing cardiovascular disease in the general Japanese population. Methods and Results: We evaluated the association between coffee consumption frequency (never, sometimes, 1-2 cups/day, 3-4 cups/day and ≥5 cups/day) and mortality from all causes, heart disease, and cerebrovascular disease, in 39,685 men and 43,124 women aged 40-79 years at baseline, in a 3-prefecture cohort study. The coffee consumption frequency was assessed on questionnaire. Cox proportional hazards regression modeling was used to assess the association between coffee consumption frequency and all-cause and cardiovascular disease mortality with adjustment for potential confounders. During 411,341 and 472,433 person-years in men and women, respectively, a total of 7,955 men and 5,725 women died. Coffee consumption frequency was inversely associated with all-cause mortality in both genders (P for trend<0.001). In addition, the risks of mortality from cerebrovascular disease in men (P for trend<0.001), and heart disease in women (P for trend=0.031) were inversely associated with coffee consumption. CONCLUSIONS: In this Japanese population, coffee drinking has a preventive effect on all-cause and on cardiovascular mortality in men and/or women.

Coffee drinking and colorectal cancer and its subsites: A pooled analysis of 8 cohort studies in Japan.

Coffee is a rich source of bioactive compounds that have potential anticarcinogenic effects. However, it remains unclear whether coffee drinking is associated with colorectal cancer. Also, despite different etiological factors involved in gut physiology, few studies have investigated this association by anatomical site of the lesion. To address these issues, this study examined the association between coffee drinking and colorectal cancer in a pooled analysis from 8 cohort studies conducted in Japan. Among 320,322 participants followed up for 4,503,274 person-years, 6,711 incident colorectal cancer cases were identified. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models and then pooled using the random effects model. Coffee drinking was not materially associated with colorectal cancer risk in men or women (pooled HR 0.92, 95% CI 0.82-1.03 in men and pooled HR 0.90, 95% CI 0.76-1.07 in women). Analysis by subsite showed a lower risk of colon cancer among female drinkers of ≥3 cups coffee/day (pooled HR 0.80, 95% CI 0.64-0.99). There was no such association in men. Coffee drinking was not associated with risk of rectal cancer in men or women. Results were virtually the same among never smokers except for an increased risk of rectal cancer associated with frequent coffee consumption. Coffee drinking may be associated with lower risk of colon cancer in Japanese women.

The association between coffee consumption and bladder cancer incidence in a pooled analysis of the Miyagi Cohort Study and Ohsaki Cohort Study.

Recent epidemiological studies of the association between coffee consumption and the risk of bladder cancer have yielded conflicting results. The aim of the present study was to examine the association between coffee consumption and the incidence of bladder cancer on the basis of pooled data from two cohort studies carried out in Miyagi Prefecture, northeastern Japan. We delivered self-administered questionnaires inquiring about the frequency of coffee consumption and other lifestyle factors in 1990 for the Miyagi Cohort Study and in 1994 for the Ohsaki Cohort Study. We followed 73 346 individuals from both cohorts and identified 274 cases of bladder cancer during 17.6 years for the Miyagi Cohort Study and 13.3 years for the Ohsaki Cohort Study. The multivariate-adjusted hazard ratios (95% confidence intervals) of bladder cancer incidence for the individuals who drank coffee occasionally, 1-2 cups/day, and 3 or more cups/day compared with never drinkers were 1.22 (0.90-1.66), 0.88 (0.61-1.26), and 0.56 (0.32-0.99), respectively (Ptrend=0.04). The inverse association remained even after stratification for smoking status. These data indicate that there is a significant inverse association between coffee consumption and the risk of bladder cancer.

Green Tea Consumption and the Risk of Incident Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study.

OBJECTIVE: Biologic studies have shown that certain components of green tea may have protective effects on neurocognition. However, because of the lack of human epidemiologic studies, the impact of green tea consumption on the incidence of dementia has never been confirmed. The objective of this cohort study was to clarify the association between green tea consumption and incident dementia. METHODS: In this 5.7-year prospective cohort study, using a questionnaire, information on daily green tea consumption and other lifestyle factors was collected from elderly Japanese individuals aged 65 years or more. Data on incident dementia were retrieved from the public Long-term Care Insurance Database. RESULTS: Among 13,645 participants, the 5.7-year rate of incident dementia was 8.7%. More frequent green tea consumption was associated with a lower risk of incident dementia (hazard ratio for ≥5 cups/day versus <1 cup/day: 0.73; 95% confidence interval: 0.61-0.87). The lower risk of incident dementia was consistent even after selecting participants who did not have subjective memory complaints at the baseline. CONCLUSION: Green tea consumption is significantly associated with a lower risk of incident dementia.

Coffee drinking and colorectal cancer risk: an evaluation based on a systematic review and meta-analysis among the Japanese population.

OBJECTIVE: It remains unclear whether coffee drinking is associated with colorectal cancer risk. We performed a systematic review and meta-analysis of epidemiologic studies on this issue among the Japanese population. METHODS: Original data were obtained from MEDLINE searches using PubMed or from searches of the 'Ichushi' database, complemented with manual searches. Meta-analysis was performed by using the random effects model to estimate the summary relative risk with 95% confidence interval according to the study design. The final judgment was made based on a consensus of the research group members with consideration for both epidemiological evidence and biological plausibility. RESULTS: We identified five cohort studies and nine case-control studies. Of these, one cohort study reported a strong inverse association (in women only), whereas three case-control studies reported a strong inverse association with colon or rectal cancer. In meta-analysis, high consumption of coffee was not appreciably associated with colorectal cancer risk among cohort studies, whereas it was associated with significantly lower risk of colorectal or colon cancer among case-control studies. The summary relative risk/odds ratio (95% confidence interval) for the highest versus lowest categories of coffee consumption was 0.95 (0.77-1.17) and 0.78 (0.65-0.95) for cohort and case-control studies, respectively. CONCLUSIONS: The evidence is insufficient to support that coffee drinking increases or decreases the risk of colorectal cancer among the Japanese population.

Association between Coffee Consumption and Incident Risk of Disabling Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study.

Epidemiological studies of the association between coffee consumption and dementia have yielded inconsistent results. Therefore, we investigated the association between coffee consumption and incident risk of dementia in an elderly Japanese population. 23,091 subjects aged ≥65 y living in Ohsaki City, northeastern Japan, responded to the baseline survey in 2006. Of these, we analyzed 13,137 subjects who gave informed consent and were not disabled at baseline. The outcome was the incidence of disabling dementia defined by usage of the Long-term Care Insurance database. We used the Cox proportional hazards regression model for multivariate analysis. During 5.7 y of follow-up period, we identified 1,107 cases of incident dementia. Overall, coffee consumption was significantly associated with a lower risk of incident dementia. The multivariate-adjusted HRs for the incidence of dementia according to coffee consumption categories (never, occasionally, 1-2 cups/d, and ≥3 cups/d) were 1.00, 0.73 (95% CI, 0.62-0.86), 0.72 (95% CI, 0.61-0.84), and 0.82 (95% CI, 0.65-1.02; p for trend = 0.009), respectively. In addition, this significant inverse association was more remarkable among women, non-smokers, and non-drinkers. Coffee consumption is significantly associated with a lower risk of incident dementia.

Relationship between serum isoflavone levels and disability-free survival among community-dwelling elderly individuals: nested case-control study of the Tsurugaya project.

BACKGROUND: The longer healthy life expectancy observed in Japan may be partly attributed to the Japanese diet. The researchers sought to examine whether serum isoflavone levels are associated with disability and death. METHODS: The researchers used a nested case-control study to compare serum isoflavones (daidzein, genistein, glycitein, and equol) levels between 165 participants that died or were certificated as disabled (cases) and 177 controls. Disability was defined by certification of long-term care insurance. Conditional logistic regression models were used to calculate the risk of isoflavones for the composite outcome. RESULTS: The proportion of cases was lower in the group with the highest levels of equol (34/91, 37%) compared with equol nonproducers (84/161, 52%). The risk of disability or death among equol producers remained reduced after adjusting for age and sex (odds ratio: 0.55, 95% confidence interval: 0.33-0.93). In a multivariate model, this risk was also unchanged (odds ratio: 0.51, 95% confidence interval: 0.27-0.96). There were no significant associations between daidzein, genistein, and glycitein with the composite endpoint. CONCLUSIONS: Higher serum equol levels, but not any other isoflavones, were inversely associated with the composite endpoint of disability and death. Although it cannot be concluded that equol per se has preventive effects on disability or death, higher equol levels appear associated with better health.

Coffee consumption and mortality due to all causes, cardiovascular disease, and cancer in Japanese women.

Coffee contains various compounds that have recently been reported to exert beneficial health effects. However, the conclusion of its relation with mortality has not yet been reached. In this study, we aimed to investigate the associations between coffee consumption and all-cause and cause-specific mortality in Japan. We included 37,742 participants (18,287 men and 19,455 women) aged 40-64 y without a history of cancer, myocardial infarction, or stroke at baseline in our analysis, based on the Miyagi Cohort Study initiated in 1990. The outcomes were mortality due to all causes, cardiovascular disease (CVD), and cancer. During the 10.3 y of follow-up, 2454 participants died, including 426 due to CVD and 724 due to cancer. In women, the multivariate hazard ratios (HR) (95% CI) for all-cause mortality in participants who drank coffee never, occasionally, 1-2 cups (150-300 mL)/d, and > or =3 cups/d were 1.00, 0.88 (0.73-1.06), 0.82 (0.66-1.02), and 0.75 (0.53-1.05), respectively (P-trend = 0.04). For CVD mortality in women, the multivariate HR (95% CI) were 1.00, 0.56 (0.36-0.86), 0.48 (0.29-0.80), and 0.45 (0.20-1.03), respectively (P-trend = 0.006). Of the specific CVD diseases, there was a strong inverse association between coffee consumption and mortality due to coronary heart disease (CHD) in women (P-trend = 0.02) but not in men. Death due to cancer was not associated with coffee consumption in either men or women, except for colorectal cancer in women. Our results suggest that coffee may have favorable effects on morality due to all causes and to CVD, especially CHD, in women.

Green tea consumption is associated with lower psychological distress in a general population: the Ohsaki Cohort 2006 Study.

BACKGROUND: Although green tea or its constituents might reduce psychological stress, the relation between green tea consumption and psychological distress has not been investigated in a large-scale study. OBJECTIVE: Our aim was to clarify whether green tea consumption is associated with lower psychological distress. DESIGN: We analyzed cross-sectional data for 42,093 Japanese individuals aged > or =40 y from the general population. Information on daily green tea consumption, psychological distress as assessed by the Kessler 6-item psychological distress scale, and other lifestyle factors was collected by using a questionnaire. We used multiple logistic regression analyses adjusted for age, sex, history of disease, body mass index, cigarette smoking, alcohol consumption, time spent walking, dietary factors, social support, and participation in community activities to investigate the relation between green tea consumption and psychological distress. RESULTS: We classified 2774 (6.6%) of the respondents as having psychological distress (Kessler 6-item psychological distress scale > or =13/24). There was an inverse association between green tea consumption and psychological distress in a model adjusted for age and sex. Although the relation was largely attenuated when possible confounding factors were adjusted for, a statistically significant inverse association remained. The odds ratio (with 95% CI) of developing psychological distress among respondents who consumed >/=5 cups of green tea/d was 0.80 (0.70, 0.91) compared with those who consumed <1 cup/d. These relations persisted when respondents were stratified by social support subgroups or by activities in communities. CONCLUSION: Green tea consumption was inversely associated with psychological distress even after adjustment for possible confounding factors.