Case-control study of green tea consumption and the risk of endometrial endometrioid adenocarcinoma.

OBJECTIVE: To investigate the association between green tea consumption and the risk of endometrial cancer restricted to endometrial endometrioid adenocarcinoma (EEA) using a case-control design in Japan. METHODS: The cases were 152 patients with histopathologically diagnosed EEA, and the controls were 285 healthy women who were matched for age and area of residence with individual cases. The subjects completed a questionnaire regarding health-related lifestyle and reproductive history, and a food frequency questionnaire. Odds ratios (ORs) of EEA for frequency of green tea consumption were calculated by conditional logistic regression analysis. RESULTS: We observed a significant inverse association between green tea consumption and the risk of EEA with a dose-response relationship. The multivariate-adjusted OR of EEA was 0.77 (95% CI: 0.37-1.58) for those in the second quartile of green tea consumption (5-6 cups/week-1 cup/day), 0.61 (0.30-1.23) in the third quartile (2-3 cups/day), and 0.33 (0.15-0.75) in the highest quartile (> or = 4 cups/day), as referenced with those in the lowest quartile (< or = 4 cups/week; p for trend = 0.007). This inverse association was consistently observed regardless of the presence or absence of factors such as obesity and menopause. CONCLUSION: Green tea consumption may be associated with a lower risk of EEA.

Alcohol consumption and suicide mortality among Japanese men: the Ohsaki Study.

The risk of suicide is well known to be increased among heavy alcohol drinkers. However, whether the risk is increased or decreased among light drinkers is still under debate. We investigated this association in a population-based sample of men in Japan. The Ohsaki Study was a population-based, prospective cohort study among Japanese adults aged from 40 to 79 years. Between October and December, 1994, 22,804 men in Miyagi Prefecture, Japan, completed a questionnaire on various health-related lifestyles, including alcohol drinking. During the subsequent 7 years follow-up, 73 participants committed suicide. We used the Cox proportional hazards regression model to estimate the hazard ratio (HR) for suicide mortality according to the quantity of alcohol consumed daily, with adjustment for potential confounders. There was a statistically significant positive and linear association between the amount of alcohol consumed and the risk of suicide: the multivariate HRs in reference to nondrinkers (95% confidence interval) were 1.2 (0.5-2.7), 1.5 (0.7-3.4), and 2.4 (1.2-4.6) in current drinkers who consumed /=45.6g of alcohol per day, respectively (P-trend=.016). Even after the early death cases were excluded, a significant linear association was observed between alcohol consumption and the risk of suicide, with the risk of suicide also being nonsignificantly higher among the light drinkers than among nondrinkers (multivariate HR=1.7). This prospective cohort study indicated a positive linear association between alcohol consumption and the risk of suicide, and the suicide risk among the light drinkers was not decreased as compared with that in nondrinkers.

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.

Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study.

CONTEXT: Green tea polyphenols have been extensively studied as cardiovascular disease and cancer chemopreventive agents in vitro and in animal studies. However, the effects of green tea consumption in humans remain unclear. OBJECTIVE: To investigate the associations between green tea consumption and all-cause and cause-specific mortality. DESIGN, SETTING, AND PARTICIPANTS: The Ohsaki National Health Insurance Cohort Study, a population-based, prospective cohort study initiated in 1994 among 40,530 Japanese adults aged 40 to 79 years without history of stroke, coronary heart disease, or cancer at baseline. Participants were followed up for up to 11 years (1995-2005) for all-cause mortality and for up to 7 years (1995-2001) for cause-specific mortality. MAIN OUTCOME MEASURES: Mortality due to cardiovascular disease, cancer, and all causes. RESULTS: Over 11 years of follow-up (follow-up rate, 86.1%), 4209 participants died, and over 7 years of follow-up (follow-up rate, 89.6%), 892 participants died of cardiovascular disease and 1134 participants died of cancer. Green tea consumption was inversely associated with mortality due to all causes and due to cardiovascular disease. The inverse association with all-cause mortality was stronger in women (P = .03 for interaction with sex). In men, the multivariate hazard ratios of mortality due to all causes associated with different green tea consumption frequencies were 1.00 (reference) for less than 1 cup/d, 0.93 (95% confidence interval [CI], 0.83-1.05) for 1 to 2 cups/d, 0.95 (95% CI, 0.85-1.06) for 3 to 4 cups/d, and 0.88 (95% CI, 0.79-0.98) for 5 or more cups/d, respectively (P = .03 for trend). The corresponding data for women were 1.00, 0.98 (95% CI, 0.84-1.15), 0.82 (95% CI, 0.70-0.95), and 0.77 (95% CI, 0.67-0.89), respectively (P<.001 for trend). The inverse association with cardiovascular disease mortality was stronger than that with all-cause mortality. This inverse association was also stronger in women (P = .08 for interaction with sex). In women, the multivariate hazard ratios of cardiovascular disease mortality across increasing green tea consumption categories were 1.00, 0.84 (95% CI, 0.63-1.12), 0.69 (95% CI, 0.52-0.93), and 0.69 (95% CI, 0.53-0.90), respectively (P = .004 for trend). Among the types of cardiovascular disease mortality, the strongest inverse association was observed for stroke mortality. In contrast, the hazard ratios of cancer mortality were not significantly different from 1.00 in all green tea categories compared with the lowest-consumption category. CONCLUSION: Green tea consumption is associated with reduced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer.

Impact of non-dietary nutrients intake on misclassification in the estimation of nutrient intake in epidemiologic study.

BACKGROUND: Few previous epidemiologic studies have evaluated the effects of non-dietary nutrient intake, such as supplements, over the counter (OTC) drugs, and prescription drugs containing vitamins or minerals, in examining the relationship between dietary factors and health outcomes. METHODS: To examine the influence of the non-dietary intake of vitamins and calcium on the estimation of nutrient intake, we conducted a cross-sectional study with 1,168 community-dwelling Japanese subjects aged 70 years or older in 2002. The subjects were asked to bring their non-dietary nutrient sources to the examining site. The dietary and non-dietary intakes of vitamins B1, C, E and calcium were obtained and the subjects were grouped into quartiles according to their dietary intake and their dietary plus non-dietary intake. The degree of agreement between these two classifications was examined to estimate the degree of misclassification. RESULTS: Among the subjects who were classified into the highest intake category for vitamin E with dietary intake plus non-dietary nutrient intake, 34.2 % were misclassified into lower category with dietary intake alone. Similarly, intake of vitamin B(1), vitamin C and calcium were misclassified 28.8%, 18.8 %, 6.2 %, respectively. CONCLUSIONS: Our data suggest that estimation of vitamin intake from dietary sources alone would yield a maximum misclassification of one-third, which would lead to misleading conclusions being drawn from epidemiologic studies. In contrast, the degree of misclassification for calcium may be relatively small.

Dietary intakes and plasma 8-iso-prostaglandin F2alpha concentrations in community-dwelling elderly Japanese: the Tsurugaya project.

We examined the association between dietary intakes and oxidative stress status in elderly Japanese. We analyzed cross-sectional data from a community-based Comprehensive Geriatric Assessment conducted in 2002. The subjects included 961 Japanese subjects aged 70 years or older who were non-daily antioxidant supplements users. We measured plasma total 8-iso-prostaglandin (PG)F(2alpha) concentrations, a measurable lipid peroxidation biomarker, using a specific enzyme immunoassay kit. Dietary intakes were assessed through a food frequency questionnaire. Subjects were divided into three groups according to their dietary intake frequencies. Logistic regression was applied to calculate the odds ratios (ORs) for being in the highest tertile of plasma 8-iso-PGF(2alpha) concentration. Frequent intake of orange or other citrus fruits, or persimmon, strawberry, or kiwi fruit was associated with lower plasma 8-iso-PGF(2alpha) concentrations, respectively. After adjustment for potential confounders, the ORs and 95% confidence intervals (CIs) for orange or other citrus fruits were 1.00 (reference), 0.66 (0.47, 0.92), and 0.58 (0.39, 0.87) (p for trend, 0.009). Intake of persimmon, strawberry, or kiwi fruit showed similar results. These associations were partly explained by vitamin C intake. Other dietary intakes had no association. Intake of fruits may have a beneficial effect against oxidative stress in elderly Japanese.

Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project 1.

BACKGROUND: Although considerable experimental and animal evidence shows that green tea may possess potent activities of neuroprotection, neurorescue, and amyloid precursor protein processing that may lead to cognitive enhancement, no human data are available. OBJECTIVE: The objective was to examine the association between green tea consumption and cognitive function in humans. DESIGN: We analyzed cross-sectional data from a community-based Comprehensive Geriatric Assessment (CGA) conducted in 2002. The subjects were 1003 Japanese subjects aged > or =70 y. They completed a self-administered questionnaire that included questions about the frequency of green tea consumption. We evaluated cognitive function by using the Mini-Mental State Examination with cutoffs of <28, <26, and <24 and calculated multivariate-adjusted odds ratios (ORs) of cognitive impairment. RESULTS: Higher consumption of green tea was associated with a lower prevalence of cognitive impairment. At the <26 cutoff, after adjustment for potential confounders, the ORs for the cognitive impairment associated with different frequencies of green tea consumption were 1.00 (reference) for < or =3 cups/wk, 0.62 (95% CI: 0.33, 1.19) for 4-6 cups/wk or 1 cup/d, and 0.46 (95% CI: 0.30, 0.72) for > or =2 cups/d (P for trend = 0.0006). Corresponding ORs were 1.00 (reference), 0.60 (95% CI: 0.35, 1.02), and 0.87 (95% CI: 0.55, 1.38) (P for trend = 0.33) for black or oolong tea and 1.00 (reference), 1.16 (95% CI: 0.78, 1.73), and 1.03 (95% CI: 0.59, 1.80) (P for trend = 0.70) for coffee. The results were essentially the same at cutoffs of <28 and <24. CONCLUSION: A higher consumption of green tea is associated with a lower prevalence of cognitive impairment in humans.

Factors affecting home-measured resting heart rate in the general population: the Ohasama study.

BACKGROUND: We recently demonstrated that a home-measured resting heart rate (HR) can predict cardiovascular disease mortality, and it is possible that the determinants of home HR are different from casual HR. Therefore, clarifying the determinants of home HR should be useful. METHODS: Home HR was obtained using a self-monitored blood pressure (BP) measuring device. The impact of factors including home-measured BP and lifestyle on home HR was examined in 1275 members of the general Japanese population aged > or =40 years. RESULTS: Multivariate linear regression analysis demonstrated that younger age (beta = -0.08, P < or = .01), current smoking (beta = 3.22, P < or = .01), female gender (beta = 2.07, P < or = .01), and sedentary lifestyle (walking for < or =1 h/day) (beta = 2.43, P < or = .01) were determinants of elevated morning home HR. No significant association was observed between home HR and home systolic BP, whereas casual HR was significantly and positively associated with casual systolic BP. The difference between casual and home HR was also significantly and positively associated with the difference between casual and home systolic BP, suggesting that positive association between BP and HR obtained in clinic settings would be a reflection of the so-called white-coat effect. CONCLUSIONS: We observed that, with the exception of BP, most determinants of home HR were consistent with the determinants observed in previous studies using casual HR. These results suggest that reduction of home HR through modification of smoking habit or sedentary lifestyle may have a potential to decrease cardiovascular risk in addition to decreasing in these modifiable risk factor per se.

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.

Joint impact of health risks on health care charges: 7-year follow-up of National Health Insurance beneficiaries in Japan (the Ohsaki Study).

BACKGROUND: The objective of this study was to examine the joint impact of modifiable health-risk factors such as smoking, obesity, and physical inactivity on direct health care charges. METHOD: We conducted a population-based prospective cohort study, with follow-up from 1995 to 2001. The participants were Japanese National Health Insurance (NHI) beneficiaries (26,110 men and women aged 40-79 years). RESULTS: 'No risk' group defined as never-smoking, body mass index (BMI) 20.0-24.9 kg/m(2), and walking for >/=1 h/day had mean health care charges of 171.6 dollars after adjustment for potential confounders. Compared with this group, the presence of smoking (SM; ever-smoking) alone, obesity alone (OB; BMI >/=25.0 kg/m(2)), or physical inactivity (PI; walking for <1 h/day) alone were associated with a 8.3%, 7.1%, or 8.0% increase in health care charges, respectively. The combinations of the risks of SM and OB, SM and PI, OB and PI, and SM and OB and PI were associated with a 11.7%, 31.4%, 16.4%, and 42.6% increase in charges, respectively. CONCLUSION: Interventions to improve modifiable health-risk factors may be a cost-effective approach for reducing health care charges as well as improving people's health.

Increased plasma 8-isoprostane levels in hypertensive subjects: the Tsurugaya Project.

To examine the relationship between 8-isoprostane and blood pressure, we measured plasma 8-isoprostane concentration and home blood pressure levels in an elderly Japanese population. Our study population comprised 569 subjects aged 70 years and over who were not receiving antihypertensive medication. On the basis of their blood pressure values, the participants were classified into three groups: normotensive (home blood pressure <135/85 mmHg), hypertensive (home blood pressure 135/85-160/90 mmHg), and severely hypertensive (home blood pressure > or =160/90 mmHg). The mean plasma 8-isoprostane level in the severely hypertensive group (21.1+/-5.2 pg/ml) was significantly higher than that in the normotensive (20.2+/-4.9 pg/ml) or hypertensive (19.7+/-5.1 pg/ml) group, and this result was unchanged when we adjusted for possible confounding factors such as age, sex, use of vitamin A, C or E supplements, smoking status, drinking status, body mass index, use of non-steroidal anti-inflammatory drugs, history of diabetes, hypercholesterolemia, home heart rate and serum creatinine level. Thus, the level of plasma 8-isoprostane appears to be elevated in older subjects with severe hypertension.