Chigusa Date

The relationship between green tea and total caffeine intake and risk for self-reported type 2 diabetes among Japanese adults.

Context Caffeine intake from coffee has been associated with a lower incidence of diabetes. Researchers have not studied the relationship of green tea, a popular beverage in Japan, where the incidence of diabetes is increasing rapidly. Contributions The authors estimated the intake of caffeine-containing beverages in a community-based survey in Japan and measured the 5-year incidence of diabetes. Greater intake of green tea or coffee was associated with a reduced incidence of diabetes. The effect of green tea was largely observed in women, was dose-related, and reflected caffeine intake. Implications Higher intake of caffeine, whether from coffee or green tea, is associated with a lower incidence of diabetes. The Editors The prevalence of type 2 diabetes has increased worldwide, particularly in Asian countries where it was previously low (1). In Japan, population-based studies have shown a 2-fold increase in the prevalence of diabetes during the past 2 decades, from 5% to 10% to 10% to 15% (2). Several cohort studies done in Europe and in the United States reported an association between coffee consumption, a major source of caffeine, and reduced risk for diabetes (3-7). Although these studies did not show any association between consumption of black tea and the risk for diabetes, they did not examine the effect of green or oolong teas, major sources of caffeine in Asian countries. Consumption of green tea is common in Japan; 80% of the population drinks green tea, and the average consumption per capita is 2 cups per day (8). We wanted to determine whether there is a relationship between consumption of green tea and the risk for type 2 diabetes and, if so, whether caffeine fully accounts for this relationship. To examine these questions, we analyzed data from a large cohort study of 19487 middle-aged men and women in 25 communities across Japan. We also examined the effect of age, sex, body mass index (BMI), family history, smoking status, alcohol use, magnesium intake, and physical activity on the association between this mode of caffeine consumption and risk for diabetes. Methods The Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study) started between 1988 and 1990. A total of 110792 individuals (46465 men and 64327 women) who were 40 to 79 years of age and living in 45 communities across Japan participated in municipal health screening examinations and completed self-administered questionnaires regarding lifestyle and medical history of cardiovascular disease and cancer (9). Informed consent was obtained before the completion of the questionnaire. Participants from 25 of the 45 communities completed 5-year follow-up surveys. Among 35690 participants (15177 men and 20513 women) who were 40 to 65 years of age at baseline without a history of type 2 diabetes, stroke, coronary heart disease, or cancer, 17413 individuals (49%; 6727 men and 10686 women) completed the 5-year follow-up questionnaire and provided valid responses on tea or coffee consumption and history of type 2 diabetes. The data from these 17413 individuals were used for the analyses. The mean age of the nonrespondents was 1 year younger for men (52.3 vs. 53.3 years of age) and did not differ for women (53.1 vs. 53.0 years of age) compared with the respondents. The mean BMI and the prevalence of a BMI of 25.0 kg/m2 or greater did not differ between the respondents and nonrespondents. Mean BMI was 22.7 kg/m2 versus 22.8 kg/m2 for men and 22.8 kg/m2 versus 22.9 kg/m2 for women, respectively; the prevalence of overweight was 18% versus 19% for men and 21% versus 22% for women, respectively. The ethical committees at Nagoya University and the University of Tsukuba approved the study. Assessment of Consumption of Tea and Coffee and Caffeine Intake At baseline, consumption of tea and coffee was assessed by using a self-administered dietary questionnaire. Participants were asked to state their average consumption of green tea, black tea, oolong tea, and coffee during the previous year. They could select any of 4 frequency responses: less than once a week, about 1 to 2 times a week, about 3 to 4 times a week, and almost every day. Participants who selected the response of almost every day were also asked to state their average consumption of these beverages in number of cups per day. We classified the categories of consumption as less than 1 cup per week, 1 to 6 cups per week, 1 to 2 cups per day, 3 to 5 cups per day, and 6 or more cups per day. The highest 2 or 3 consumption categories were combined for coffee, black tea, and oolong tea because of the small number of participants in these categories. The consumption of decaffeinated coffee or tea was not recorded because these products were not commercially available in Japan in the early 1990s. The total intake of caffeine was calculated by adding the caffeine content from each specific beverage (1 cup for coffee or tea) and multiplying it by the participants weight proportional to the frequency of caffeine use. We estimated the size of the cup for each beverage from a validation study (10) and the caffeine content per 100 mL of each beverage from the Japan Food Tables (11). The estimated caffeine content was 153 mg per cup (170 mL) of coffee, 30 mg per cup (200 mL) of green tea, 51 mg per cup (170 mL) of black tea, and 38 mg per cup (190 mL) of oolong tea. The mean caffeine intake was 229 mg/d for men and 215 mg/d for women. Relative proportions of caffeine intake by beverage were 46% from green tea, 44% to 47% from coffee, 3% from black tea, and 4% to 5% from oolong tea. For reproducibility, the Spearman correlation coefficients between the 2 questionnaires, administered 1 year apart for 85 participants (8 men and 77 women), were 0.79 for green tea, 0.87 for coffee, 0.77 for black tea, and 0.56 for oolong tea (10). The validity of the data was confirmed for the 85 participants by comparing the data from the questionnaire with those from four 3-day dietary records collected approximately 3 to 4 months apart (10). The mean frequency of consumption of green tea was 25.4 cups per week according to the questionnaire and 30.1 cups per week according to four 1-week dietary records (Spearman correlation coefficient, 0.47). The respective mean frequencies were 8.0 cups and 7.1 cups per week with a correlation coefficient of 0.79 for coffee, 1.4 cups and 1.6 cups per week with a correlation coefficient of 0.70 for black tea, and 1.8 cups and 1.2 cups per week with a correlation coefficient of 0.55 for oolong tea. When we restricted the data to the 77 women, the results were essentially the same. Assessment of Diabetes Cases Participants who reported having diabetes newly diagnosed by physicians on the 5-year follow-up questionnaire were considered to have incident diabetes. To examine the validity of self-reporting of diabetes, we compared self-report data with laboratory findings and treatment status in a sample of 1230 men and 1837 women. We considered elevated glucose concentrations (fasting serum glucose concentration 7.8 mmol/L [140 mg/dL] or a randomly measured concentration of 11.1 mmol/L [200 mg/dL]) or treatment with oral hypoglycemic agents or insulin to indicate new cases of diabetes. Recent criteria from the American Diabetes Association (12) were not used because the cases in our study were diagnosed before 1995. The sensitivity of self-reporting was 70% for men and 75% for women; the specificity was 95% for men and 98% for women. Statistical Analysis To examine potential confounding variables reported from previous studies (3-7), we presented baseline characteristics according to the frequency of consumption for each beverage. Tests for trends were conducted by using the median values of confounding variables in each category of beverage; the linear regression model was used for continuous variables, and the logistic regression model was used for categorical variables. The odds ratios for incident type 2 diabetes were calculated in each category of beverage consumption and in each quartile of caffeine intake; less than 1 cup per week or the lowest quartile was used as the reference category. We estimated age, sex, and BMI-adjusted odds ratios and multivariable odds ratios using the logistic regression model, adjusting for age (in years), sex, sex-specific quintiles of BMI (weight in kilograms divided by the square of height in meters), parental history of diabetes (yes or no), smoking status (never, former, or current [1 to 19, 20 to 29, or 30 cigarettes/d]), alcohol intake (never, former, or current [1 to 22, 23 to 45, 46 to 68, or 69 g/d]), sex-specific quintiles of magnesium intake, hours of walking (<0.5, 0.5, 0.6 to 0.9, and 1.0 h/d), and hours of participation in sports (<1, 1 to 2, 3 to 4, and 5 h/wk). Sex-specific quintiles of BMI and magnesium intake were used because of different distributions between the sexes. We adjusted for magnesium intake because previous cohort studies indicated an inverse association between magnesium intake and risk for diabetes (13, 14). We conducted a test for trend by treating median values of each category of beverage or caffeine intake as continuous variables. We examined the association between caffeine intake and the risk for diabetes stratified by age group (40 to 54 years and 55 to 65 years), sex, family history of diabetes (yes or no), current smoking status (yes or no), current alcohol intake (yes or no), magnesium intake (below and above the sex-specific median), BMI (<25.0 kg/m2 and 25.0 kg/m2), hours of walking (<0.5 and 0.5 h/d), and hours of participation in sports (<5 and 5 h/wk). The interactions with these stratified variables were tested by using cross-product terms of caffeine intake and the stratified variables. All analyses were conducted by using the SAS statistical package, version 8.2 (SAS Institute Inc., Cary, North Carolina). P values for statistical tests were 2-tailed, and 95% CIs were estimated. Role of the

Risk factors for cerebral hemorrhage and cerebral infarction in a Japanese rural community.

A ten-year follow-up study of stroke among residents 40 years and older in a rural community located on Shikoku Island, Japan, was completed in 1977. The response rate for the initial examinations was 85% of 920 males and 90% of 1,012 females. Seven hundred and seventy-two males and 901 females who were initially free of stroke were followed from July 1967 through June 1977. The incidence of all strokes was 10.47 per thousand person-years for males and 6.41 per thousand person-years for females. The statistically significant risk factors for stroke were age, male sex, elevated blood pressure, ECG abnormalities, and funduscopic abnormalities. Elevated blood pressure was the strongest risk factor and mean arterial pressure was the best predictive measure. Twice as high a proportion of strokes were subclassified as cerebral hemorrhage (26%) in this study as have been reported in comparable studies in the United States (12–15%). An inverse relationship between serum cholesterol levels and cerebral hemorrhage incidence, but not cerebral infarct, was observed. High alcohol intake was a risk factor for cerebral hemorrhage but not for cerebral infarct. No relationship between stroke and weight was observed despite the relationship of stroke to blood pressure and of weight to blood pressure.

Comparison of relative validity of food group intakes estimated by comprehensive and brief-type self-administered diet history questionnaires against 16 d dietary records in Japanese adults.

OBJECTIVE To compare the relative validity of food group intakes derived from a comprehensive self-administered diet history questionnaire (DHQ) and a brief-type DHQ (BDHQ) developed for the assessment of Japanese diets during the previous month using semi-weighed dietary records (DR) as a reference method. DESIGN Between November 2002 and September 2003, a 4 d DR (covering four non-consecutive days), a DHQ (150-item semi-quantitative questionnaire) and a BDHQ (fifty-eight-item fixed-portion-type questionnaire) were completed four times (once per season) at 3-month intervals. SETTING Three areas in Japan: Osaka, Nagano and Tottori. SUBJECTS Ninety-two Japanese women aged 31-69 years and ninety-two Japanese men aged 32-76 years. RESULTS Median food group intakes were estimated well for approximately half of the food groups. No statistically significant differences were noted between a 16 d DR and the first DHQ (DHQ1) or between the DR and the first BDHQ (BDHQ1) in fifteen (44 %) and fifteen (52 %) food items for women and in fourteen (41 %) and sixteen (55 %) food items for men, respectively, indicating that both questionnaires estimated median values reasonably well. Median Spearmans correlation coefficients with the DR were 0·43 (range: -0·09 to 0·77) for DHQ1 and 0·44 (range: 0·14 to 0·82) for BDHQ1 in women, with respective values of 0·44 (range: 0·08 to 0·87) and 0·48 (range: 0·22 to 0·83) in men, indicating reasonable ranking ability. Similar results were observed for mean values of the four DHQ and BDHQ. CONCLUSIONS In terms of food intake estimates, both the DHQ and the BDHQ showed reasonable validity.

Dietary risk factors for inflammatory bowel disease A Multicenter Case‐Control Study in Japan

&NA; To evaluate the role of dietary factors in the etiology of inflammatory bowel disease (IBD), we conducted a multicenter hospital‐based case‐control study in a Japanese population. Cases were IBD patients aged 15 to 34 years [ulcerative colitis (UC) 111 patients; Crohns disease (CD) 128 patients] within 3 years after diagnosis in 13 hospitals. One control subject was recruited for each case who was matched for sex, age, and hospital. A semiquantitative food frequency questionnaire was used to estimate preillness intakes of food groups and nutrients. All the available control subjects (n = 219) were pooled, and unconditional logistic models were applied to calculate odds ratios (ORs). In the food groups, a higher consumption of sweets was positively associated with UC risk [OR for the highest versus lowest quartile, 2.86; 95% confidence interval (CI), 1.24 to 6.57], whereas the consumption of sugars and sweeteners (OR, 2.12; 95% CI, 1.08 to 4.17), sweets (OR, 2.83; 95% CI, 1.38 to 5.83), fats and oils (OR, 2.64; 95% CI, 1.29 to 5.39), and fish and shellfish (OR, 2.41; 95% CI, 1.18‐4.89) were positively associated with CD risk. In respect to nutrients, the intake of vitamin C (OR, 0.45; 95% CI, 0.21 to 0.99) was negatively related to UC risk, while the intake of total fat (OR, 2.86; 95% CI, 1.39 to 5.90), monounsaturated fatty acids (OR, 2.49; 95% CI, 1.23 to 5.03) and polyunsaturated fatty acids (OR, 2.31; 95% CI, 1.12 to 4.79), vitamin E (OR, 3.23; 95% CI, 1.45 to 7.17), and n‐3 (OR, 3.24; 95% CI, 1.52 to 6.88) and n‐6 fatty acids (OR, 2.57; 95% CI, 1.24 to 5.32) was positively associated with CD risk. Although this study suffers from the shortcoming of recall bias, which is inherent in most retrospective studies (prospective studies are warranted to confirm the associations between diet and IBD risk), the present findings suggest the importance of dietary factors for IBD prevention.

Both Comprehensive and Brief Self-Administered Diet History Questionnaires Satisfactorily Rank Nutrient Intakes in Japanese Adults

Background A comprehensive self-administered diet history questionnaire (DHQ: 150-item semi-quantitative questionnaire) and a brief self-administered DHQ (BDHQ: 58-item fixed-portion–type questionnaire) were developed for assessing Japanese diets. We compared the relative validity of nutrient intake derived from DHQ with that from the BDHQ, using semi-weighed 16-day dietary records (DRs) as reference. Methods Ninety-two Japanese women aged 31 to 69 years and 92 Japanese men aged 32 to 76 years completed a 4-nonconsecutive-day DR, a DHQ, and a BDHQ 4 times each (once per season) in 3 areas of Japan (Osaka, Nagano, and Tottori). Results No significant differences were seen in estimates of energy-adjusted intakes of 42 selected nutrients (based on the residual method) between the 16-day DRs and the first DHQ (DHQ1) or between the DR and the first BDHQ (BDHQ1) for 18 (43%) and 14 (33%) nutrients, respectively, among women and for 4 (10%) and 21 (50%) nutrients among men. The median (interquartile range) Pearson correlation coefficients with the DR for energy-adjusted intakes of the 42 nutrients were 0.57 (0.50 to 0.64) for the DHQ1 and 0.54 (0.45 to 0.61) for the BDHQ1 in women; in men, the respective values were 0.50 (0.42 to 0.59) and 0.56 (0.41 to 0.63). Similar results were observed for the means of the 4 DHQs and BDHQs. Conclusions The DHQ and BDHQ had satisfactory ranking ability for the energy-adjusted intakes of many nutrients among the present Japanese population, although these instruments were satisfactory in estimating mean values for only a small number of nutrients.

Perceived mental stress and mortality from cardiovascular disease among Japanese men and women : the Japan Collaborative Cohort Study for Evaluation of Cancer Risk Sponsored by Monbusho (JACC Study)

Background—Perceived mental stress has been associated with risk of coronary heart disease (CHD) in white men, but no prospective data are available for other ethnic groups. Methods and Results—From 1988 to 1990, a total of 73 424 Japanese (30 180 men and 43 244 women), aged 40 to 79 years, without a history of stroke, CHD, or cancer completed a lifestyle questionnaire including perception of mental stress under the Japan Collaborative Cohort Study for Evaluation of Cancer Risk Sponsored by Monbusho (JACC Study). Systematic surveillance was completed until the end of 1997, with a 580 378 person-year follow-up, and the underlying causes of death were determined according to the International Classification of Diseases, 10th revision. For women, there were 316 with total stroke, 113 with CHD, and 643 with total cardiovascular disease (CVD); for men, there were 341, 168, and 778, respectively. Women who reported high stress had a 2-fold higher age-adjusted risk of mortality from total stroke and CHD and 1.5-fold higher risk of total CVD compared with those who reported low stress. Further adjustment for known cardiovascular risk factors and selected psychological variables did not alter the associations materially. The multivariate relative risk for women who perceived high stress versus low stress was 2.24 (95% CI 1.52 to 3.31, P <0.001) for total stroke, 2.28 (95% CI 1.17 to 4.43, P =0.02) for CHD, and 1.64 (95% CI 1.25 to 2.16, P <0.001) for total CVD. For men, these relations were generally weaker but suggestive of myocardial infarction. Conclusions—Perceived mental stress was associated with increased mortality from stroke for women and with CHD for men and women.

Fish, ω-3 Polyunsaturated Fatty Acids, and Mortality From Cardiovascular Diseases in a Nationwide Community-Based Cohort of Japanese Men and Women: The JACC (Japan Collaborative Cohort Study for Evaluation of Cancer Risk) Study

OBJECTIVES The objective of our study was to test the hypothesis that fish or omega-3 polyunsaturated fatty acids (PUFA) intakes would be inversely associated with risks of mortality from ischemic heart disease, cardiac arrest, heart failure, stroke, and total cardiovascular disease. BACKGROUND Data on associations of dietary intake of fish and of omega-3 PUFA with risk of cardiovascular disease among Asian societies have been limited. METHODS We conducted a prospective study consisting of 57,972 Japanese men and women. Dietary intakes of fish and omega-3 PUFA were determined by food frequency questionnaire, and participants were followed up for 12.7 years. Hazard ratios and 95% confidence intervals were calculated according to quintiles of fish or omega-3 PUFA intake. RESULTS We observed generally inverse associations of fish and omega-3 PUFA intakes with risks of mortality from heart failure (multivariable hazard ratio [95% confidence interval] for highest versus lowest quintiles = 0.76 [0.53 to 1.09] for fish and 0.58 [0.36 to 0.93] for omega-3 PUFA). Associations with ischemic heart disease or myocardial infarction were relatively weak and not statistically significant after adjustment for potential risk factors. Neither fish nor omega-3 PUFA dietary intake was associated with mortality from total stroke, its subtypes, or cardiac arrest. For mortality from total cardiovascular disease, intakes of fish and omega-3 PUFA were associated with 18% to 19% lower risk. CONCLUSIONS We found an inverse association between fish and omega-3 PUFA dietary intakes and cardiovascular mortality, especially for heart failure, suggesting a protective effect of fish intake on cardiovascular diseases.

A 15.5-year follow-up study of stroke in a Japanese provincial city : The Shibata Study

BACKGROUND AND PURPOSE Change toward Western lifestyles, particularly during the high economic growth period (approximately 1960 to 1975), dynamically altered stroke frequency and the distribution of risk factors in the Japanese. We reexamined their association after this environmental change by a cohort study. METHODS The cohort (2302 subjects) comprised residents aged 40 years or older of the Akadani-Ijimino district in Shibata City, Niigata Prefecture, Japan, who were followed up from 1977 for 15.5 years. RESULTS Crude incidence rates per 1000 person-years for all strokes were 5.22 for men and 4.36 for women (3.02 and 2.18 for cerebral infarction, 0.65 and 1.06 for intracerebral hemorrhage, and 0.41 and 0.34 for subarachnoid hemorrhage, respectively). Multivariate analyses performed with the Cox proportional hazard model revealed these risk factors to be independently significant: for cerebral infarction in men, age, blood pressure, atrial fibrillation, albuminuria, funduscopic abnormality, and current smoking: for cerebral infarction in women, age, atrial fibrillation, and history of ischemic heart disease; for intracerebral hemorrhage in men, age and funduscopic abnormality; for intracerebral hemorrhage in women, age, blood pressure, and light physical activity; for all strokes in men, age, blood pressure, atrial fibrillation, albuminuria, funduscopic abnormality, current smoking, and heavy physical activity; and for all strokes in women, age, atrial fibrillation, and light physical activity. CONCLUSIONS Most traditional risk factors, including blood pressure and its related organ diseases, were confirmed, but serum total cholesterol had almost no effect. Physical activity had both negative and positive effects on stroke risk. In these findings, however, some differences related to sex were also observed.

Clinical ResearchDiet and Cardiovascular DiseaseFish, ω-3 Polyunsaturated Fatty Acids, and Mortality From Cardiovascular Diseases in a Nationwide Community-Based Cohort of Japanese Men and Women: The JACC (Japan Collaborative Cohort Study for Evaluation of Cancer Risk) Study

OBJECTIVES The objective of our study was to test the hypothesis that fish or omega-3 polyunsaturated fatty acids (PUFA) intakes would be inversely associated with risks of mortality from ischemic heart disease, cardiac arrest, heart failure, stroke, and total cardiovascular disease. BACKGROUND Data on associations of dietary intake of fish and of omega-3 PUFA with risk of cardiovascular disease among Asian societies have been limited. METHODS We conducted a prospective study consisting of 57,972 Japanese men and women. Dietary intakes of fish and omega-3 PUFA were determined by food frequency questionnaire, and participants were followed up for 12.7 years. Hazard ratios and 95% confidence intervals were calculated according to quintiles of fish or omega-3 PUFA intake. RESULTS We observed generally inverse associations of fish and omega-3 PUFA intakes with risks of mortality from heart failure (multivariable hazard ratio [95% confidence interval] for highest versus lowest quintiles = 0.76 [0.53 to 1.09] for fish and 0.58 [0.36 to 0.93] for omega-3 PUFA). Associations with ischemic heart disease or myocardial infarction were relatively weak and not statistically significant after adjustment for potential risk factors. Neither fish nor omega-3 PUFA dietary intake was associated with mortality from total stroke, its subtypes, or cardiac arrest. For mortality from total cardiovascular disease, intakes of fish and omega-3 PUFA were associated with 18% to 19% lower risk. CONCLUSIONS We found an inverse association between fish and omega-3 PUFA dietary intakes and cardiovascular mortality, especially for heart failure, suggesting a protective effect of fish intake on cardiovascular diseases.

Coffee, green tea, black tea and oolong tea consumption and risk of mortality from cardiovascular disease in Japanese men and women

Background The effects of coffee and green, black and oolong teas and caffeine intake on cardiovascular disease (CVD) mortality have not been well defined in Asian countries. Methods To examine the relationship between the consumption of these beverages and risk of mortality from CVD, 76 979 individuals aged 40–79 years free of stroke, coronary heart disease (CHD) and cancer at entry were prospectively followed. The daily consumption of beverages was assessed by questionnaires. Results 1362 deaths were documented from strokes and 650 deaths from CHD after 1 010 787 person-years of follow-up. Compared with non-drinkers of coffee, the multivariable HR and 95% CI for those drinking 1–6 cups/week, 1–2 cups/day and ≥3 cups/day were 0.78 (0.50 to 1.20), 0.67 (0.47 to 0.96) and 0.45 (0.17 to 0.87) for strokes among men (p=0.009 for trend). Compared with non-drinkers of green tea, the multivariable HR for those drinking 1–6 cups/week, 1–2 cups/day, 3–5 cups/day and ≥6 cups/day were 0.34 (0.06–1.75), 0.28 (0.07–1.11), 0.39 (0.18–0.85) and 0.42 (0.17–0.88) for CHD among women (p=0.038 for trend). As for oolong tea, the multivariable HR of those drinking 1–6 cups/week and ≥1 cups/day were 1.00 (0.65–1.55) and 0.39 (0.17–0.88) for total CVD among men (p=0.049 for trend). Risk reduction for total CVD across categories of caffeine intake was most prominently observed in the second highest quintile, with a 38% lower risk among men and 22% among women. Conclusions Consumption of coffee, green tea and oolong tea and total caffeine intake was associated with a reduced risk of mortality from CVD.