Reproducibility and dietary correlates of plasma polyphenols in the JPHC-NEXT Protocol Area study.

BACKGROUND: In recent years, an increasing number of epidemiological studies have suggested a role of polyphenols in the prevention of chronic diseases. Prospective cohort studies have typically measured polyphenol concentrations in a single blood sample and the reproducibility of plasma polyphenol measurements is largely unknown. OBJECTIVE: We evaluated the reproducibility of 35 plasma polyphenols collected at an interval of 1-year. We also examined correlations of these polyphenols with food group intakes calculated from weighed food records (WFR) and food frequency questionnaire (FFQ). METHODS: The study included 227 middle-aged participants from the JPHC-NEXT Protocol Area in Japan. We measured 35 polyphenols in plasma collected at two points 1-year apart. Food group intakes were calculated from 12-day WFR and FFQ. For the reproducibility analysis, the intraclass correlation coefficient (ICC) of 35 polyphenol concentrations were examined between the two points. Pearson's partial correlations was used to assess the correlation between polyphenols and food groups. RESULTS: Moderate- to high ICCs were observed for tea-originated polyphenols such as gallic acid, quercetin, epigallocatechin, and kaempferol - and coffee-derived polyphenols, such as caffeic acid, and ferulic acid. For the dietary analyses, moderate correlations were observed for non-alcoholic beverages intake and epigallocatechin, epicatechin, catechin, and gallic acid. For green tea, higher correlations were observed with these polyphenols. CONCLUSION: Plasma concentrations of tea and coffee-related polyphenols, except for catechin, had good reproducibility over a 1-year period. The correlations between intake of non-alcoholic beverages, particularly green tea, and tea polyphenols, indicated moderate- to high correlations.

Sugary drink consumption and risk of kidney and bladder cancer in Japanese adults.

Globally, sugary drinks are widely consumed, however, few epidemiologic studies have investigated the association between sugary drink consumption and risk of kidney and bladder cancer. We examined the association of sugary drinks with risk of kidney and bladder cancer in 73,024 participants from the Japan Public Health Center-based Prospective Study who reported no history of cancer. Sugary drink consumption was assessed using a validated food frequency questionnaire at study baseline (1995-1999). Individuals were followed to December 31, 2013. Multivariable Cox proportional hazards regression models were used to calculate hazard ratios (HR) and 95% confidence intervals (CIs). During 1,069,815 person years of follow-up, 169 kidney cancer and 297 bladder cancer cases were documented. After adjusting for potential confounders, no greater risk of kidney and bladder cancer was observed. However, sugary drink consumption was positively associated with the risk of kidney cancer (HR for 100 ml/day increase in consumption was 1.11 [95% CI 1.01-1.22]) and bladder cancer (HR for 100 ml/d increase in consumption was 1.11 [95% CI 1.01-1.22]) among women after exclusion of cases diagnosed in the first three years of follow-up. In this large prospective cohort, consumption of sugary drinks was significantly associated with a small increase in hazard ratio for kidney and bladder cancer among women after exclusion of cases diagnosed within the first three years.

Dietary Acrylamide Intake and the Risk of Pancreatic Cancer: The Japan Public Health Center-Based Prospective Study.

Acrylamide is a probable carcinogen in humans. Few studies have assessed dietary acrylamide intake and the risk of pancreatic cancer; however, these studies are based on Western populations. Our purpose was to investigate the association of dietary acrylamide intake with the risk of pancreatic cancer utilizing data from the Japan Public Health Center-based Prospective Study. We evaluated the data of 89,729 participants aged 45-74 years, who replied to a questionnaire on past medical history and lifestyle habits from 1995-1998. Dietary acrylamide intake was estimated utilizing a validated food frequency questionnaire. We calculated the hazard ratios and 95% confidence intervals by using Cox proportional-hazards regression models. The average follow-up was 15.2 years, and 576 cases of pancreatic cancer were diagnosed. In the multivariate-adjusted model, an association between dietary acrylamide intake and pancreatic cancer risk was not demonstrated (hazard ratio for the highest vs. lowest quartile = 0.83, 95% confidence interval: 0.65-1.05, p for trend = 0.07). Furthermore, in the analyses stratified by sex, smoking status, coffee consumption, green tea consumption, alcohol consumption, and body mass index, no significant association was detected. Dietary acrylamide intake was not associated with the pancreatic cancer risk in Japanese individuals.

Dietary Acrylamide Intake and the Risk of Liver Cancer: The Japan Public Health Center-Based Prospective Study.

Acrylamide has been studied for its carcinogenicity in experimental animals, causing tumors at several organ sites, and has been considered probably carcinogenic to humans as well. Given the small number of epidemiological studies that have been conducted, it is still uncertain whether the consumption of acrylamide is associated with liver cancer. Therefore, we investigated a study to determine the possible relationship between acrylamide intake and the risk of developing liver cancer in the Japanese population. A total of 85,305 participants, from the Japan Public Health Center-based Prospective Study, who provided a validated food-frequency questionnaire were enrolled between 1995 and 1998. During a median of 16.0 years follow-up, 744 new liver cancer cases were identified. Compared to the lowest tertile of acrylamide consumption (<4.8 µg/day), the multivariate hazard ratio (HR) for the highest tertile (≥7.6 µg/day) was 0.79 (95% confidence interval [CI] = 0.65-0.95) for liver cancer using multivariable model 1, adjusted for smoking status, body mass index (BMI), physical activity, medical history, and alcohol consumption; whereas the inverse relationship disappeared after additionally adjusting for coffee consumption in multivariable model 2 with HR of 1.08 (95% CI = 0.87-1.34) for the highest tertile. The effect of dietary acrylamide intake on the risk of liver cancer was not observed in the Japanese population.

Dietary acrylamide intake and the risk of endometrial or ovarian cancers in Japanese women.

A meta-analysis published in 2015 noted a marginally increased risk of endometrial and ovarian cancers in non-smoking women with dietary acrylamide intake, but only a few studies were included, and they were limited to Western countries. The aim of this study was to investigate the association between dietary acrylamide intake and endometrial or ovarian cancer risk in the Japan Public Health Center-based Prospective Study (JPHC Study). In this prospective cohort study, 47 185 participants aged 45-74 years at the follow-up starting point in the JPHC Study were enrolled. Dietary acrylamide intake was assessed using a validated food frequency questionnaire. Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (95%CI). In participants with endometrial and ovarian cancer, the average follow-up periods were 15.5 and 15.6 years, respectively, and 161 and 122 cases of endometrial and ovarian cancer were diagnosed, respectively. Energy-adjusted dietary acrylamide intake was negatively associated with endometrial cancer, but the association disappeared after adjusting for coffee consumption with an adjusted HR for the highest vs lowest tertile of 0.85 (95%CI: 0.54-1.33). No association was observed, however, for ovarian cancer (adjusted HR, 0.77; 95%CI: 0.49-1.23). Furthermore, after stratifying by smoking status, coffee consumption, alcohol consumption, body mass index, and menopause status, no association was observed. Dietary acrylamide intake was not associated with the risk of endometrial or ovarian cancer in Japanese women with a relatively lower dietary intake of acrylamide compared with Western populations.

Dietary consumption of antioxidant vitamins and subsequent lung cancer risk: The Japan Public Health Center-based prospective study.

While many epidemiological studies have studied the association between lung cancer risk and fruits and vegetable consumption (the major sources of antioxidant vitamins), only a few have investigated the direct association with antioxidants in consideration of cancer subtypes and smoking status. Here, we examined the association between consumption of antioxidant vitamins and lung cancer risk in one of the largest prospective cohort studies in Japan. We investigated the association of dietary antioxidant vitamins intake, namely retinol, vitamin C, vitamin E, α-carotene, and ß-carotene and subsequent incidence of lung cancer among 38,207 men and 41,498 women in the Japan Public Health Center-based prospective study. Cox proportional hazard regression was performed with adjustment for potential confounders and by strata of cancer subtypes and smoking status. Antioxidant and other dietary intakes were assessed using a food frequency questionnaire (FFQ). During 1,233,096 person-years of follow-up between 1995 and 2013, a total of 1,690 lung cancer cases were newly diagnosed. In a multivariate regression model, while higher retinol intake was positively associated with overall lung cancer risk in men (HR 1.26; 95% CI 1.05-1.51; ptrend = 0.003), the estimates were more evident with small cell carcinoma (HR 1.92; 95% CI 1.13-3.24; ptrend < 0.001). Null associations were observed for other antioxidant vitamins. Our prospective study suggests that higher consumption of retinol may be associated with an increased risk of lung cancer in men, especially with small cell carcinoma, although confirmation is required.

Association between green tea/coffee consumption and biliary tract cancer: A population-based cohort study in Japan.

Green tea and coffee consumption may decrease the risk of some types of cancers. However, their effects on biliary tract cancer (BTC) have been poorly understood. In this population-based prospective cohort study in Japan, we investigated the association of green tea (total green tea, Sencha, and Bancha/Genmaicha) and coffee consumption with the risk for BTC and its subtypes, gallbladder cancer, and extrahepatic bile duct cancer. The hazard ratios and 95% confidence intervals were calculated using the Cox proportional hazard model. A total of 89 555 people aged 45-74 years were enrolled between 1995 and 1999 and followed up for 1 138 623 person-years until 2010, during which 284 cases of BTC were identified. Consumption of >720 mL/day green tea was significantly associated with decreased risk compared with consumption of ≤120 mL/day (hazard ratio = 0.67 [95% confidence interval, 0.46-0.97]), and a non-significant trend of decreased risk associated with increased consumption was observed (P-trend = 0.095). In the analysis according to the location of the primary tumor, consuming >120 mL green tea tended to be associated with decreased risk of gallbladder cancer and extrahepatic bile duct cancer. When Sencha and Bancha/Genmaicha were analyzed separately, we observed a non-significant trend of decreased risk of BTC associated with Sencha but no association with Bancha/Genmaicha. For coffee, there was no clear association with biliary tract, gallbladder, or extrahepatic bile duct cancer. Our findings suggest that high green tea consumption may lower the risk of BTC, and the effect may be attributable to Sencha consumption.

Fish, n - 3 polyunsaturated fatty acids and n - 6 polyunsaturated fatty acids intake and breast cancer risk: The Japan Public Health Center-based prospective study.

Limited and inconsistent studies exist on the association between the intake of fish, n - 3 polyunsaturated fatty acids (PUFA) and n - 6 PUFA and breast cancer. Fish and n - 3 PUFA support various body functions and are thought to reduce the carcinogenesis risk while n - 6 PUFA may have a positive association with cancer risk. We examined the association between intake of fish, n - 3 PUFA [including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and alpha-linolenic acid (ALA)] and n - 6 PUFA and breast cancer with subanalyses on estrogen (ER) and progesterone receptor (PR) status. We investigated 38,234 Japanese women aged 45-74 years from the Japan Public Health Center-based prospective study (JPHC study), and during 14.1 years of follow-up time, 556 breast cancer cases were newly diagnosed. Breast cancer risk was not associated with the intake of total fish, n - 3 PUFA and n - 6 PUFA when analyzed in totality through multivariable Cox proportional hazards regression models with age as the time scale. Intake of total n - 6 was positively associated with the development of ER+PR+ tumors [multivariable-adjusted HR Q4 vs. Q1 = 2.94 (95% CI: 1.26-6.89; ptrend = 0.02)]. Intake of EPA was associated with a decreased breast cancer risk for ER+PR+ tumors [multivariable-adjusted HR Q2 vs. Q1 = 0.47 (95% CI: 0.25-0.89; ptrend =0.47)]. While the overall association between the intake of total fish, n - 3 PUFA and n - 6 PUFA and breast cancer risk is null, for ER+PR+ tumors, a positive association was seen between n - 6 intake and breast cancer, and a marginally significant inverse association was observed for EPA intake.

The impact of green tea and coffee consumption on the reduced risk of stroke incidence in Japanese population: the Japan public health center-based study cohort.

BACKGROUND AND PURPOSE: Few prospective studies have examined the impact of both green tea and coffee consumption on strokes. We investigated the association of the combination of those consumption with stroke incidence in a general population. METHODS: We studied 82 369 Japanese (aged 45-74 years; without cardiovascular disease [CVD] or cancer in 1995 and 1998 for Cohort I and II, respectively) who received 13 years of mean follow-up through the end of 2007. Green tea and coffee consumption was assessed by self-administered food frequency questionnaire at baseline. RESULTS: In the 1 066 718 person-years of follow-up, we documented the incidence of strokes (n=3425) and coronary heart disease (n=910). Compared with seldom drinking green tea, the multivariable-adjusted hazard ratios (95% confidence intervals) of all strokes were 0.86 (0.78-0.95) and 0.80 (0.73-0.89) in green tea 2 to 3 and ≥ 4 cups/d, respectively. Higher green tea consumption was associated with inverse risks of CVD and strokes subtypes. Compared with seldom drinking coffee, the multivariable-adjusted hazard ratios (95% confidence intervals) of all strokes were 0.89 (0.80-0.99), 0.80 (0.72-0.90), and 0.81 (0.72-0.91) for coffee 3 to 6 times/week and 1 and ≥ 2 times/day, respectively. Coffee consumption was associated with an inverse risk of CVD and cerebral infarction. Higher green tea or coffee consumption reduced the risks of CVD and stroke subtypes (especially in intracerebral hemorrhage, P for interaction between green tea and coffee=0.04). None of the significant association was observed in coronary heart disease. CONCLUSIONS: Higher green tea and coffee consumption were inversely associated with risk of CVD and stroke in general population.

Use of vitamin supplements and risk of total cancer and cardiovascular disease among the Japanese general population: a population-based survey.

BACKGROUND: Despite the popular use of vitamin supplements and several prospective cohort studies investigating their effect on cancer incidence and cardiovascular disease (CVD), scientific data supporting their benefits remain controversial. Inconsistent results may be partly explained by the fact that use of supplements is an inconsistent behavior in individuals. We examined whether vitamin supplement use patterns affect cancer and CVD risk in a population-based cohort study in Japan. METHODS: A total of 28,903 men and 33,726 women in the Japan Public Health Center-based Prospective Study cohort, who answered questions about vitamin supplement use in the first survey from 1990-1994 and the second survey from 1995-1998, were categorized into four groups (never use, past use, recent use, and consistent use) and followed to the end of 2006 for cancer and 2005 for CVD. Sex-specific hazard ratios (HRs) and 95% confidence intervals (95% CIs) were used to describe the relative risks of cancer and CVD associated with vitamin supplement use. RESULTS: During follow-up, 4501 cancer and 1858 CVD cases were identified. Multivariate adjusted analysis revealed no association of any pattern of vitamin supplement use with the risk of cancer and CVD in men. In women, consistent use was associated with lower risk of CVD (HR 0.60, 95% CI 0.41-0.89), whereas past (HR 1.17, 95% CI 1.02-1.33) and recent use (HR 1.24, 95% CI 1.01-1.52) were associated with higher risk of cancer. CONCLUSIONS: To our knowledge, this is the first prospective cohort study to examine simultaneously the associations between vitamin supplement use patterns and risk of cancer and CVD. This prospective cohort study demonstrated that vitamin supplement use has little effect on the risk of cancer or CVD in men. In women, however, consistent vitamin supplement use might reduce the risk of CVD. Elevated risk of cancer associated with past and recent use of vitamin supplements in women may be partly explained by preexisting diseases or unhealthy background, but we could not totally control for this in our study.

Intake of folate, vitamin B6 and vitamin B12 and the risk of CHD: the Japan Public Health Center-Based Prospective Study Cohort I.

OBJECTIVE: To investigate the association of dietary folate, vitamin B(6) (VB(6)) and vitamin B(12) (VB(12)) with the risk of coronary heart disease among middle-aged persons. METHODS: A total of 40,803 subjects aged 40-59 years living in the community who were free of prior diagnoses of cardiovascular disease and cancer and who completed a food frequency questionnaire were followed from 1990-1992 to the end of 2001 in the Japan Public Health Center-based Prospective Study. RESULTS: After 468,472 person-years of follow-up, 251 coronary heart disease incidents were documented. Coronary heart disease and definite myocardial infarction were inversely associated with dietary intake of folate, VB(6) and VB(12) after adjustment for age and sex, but the associations were attenuated after further adjustment for smoking, dietary and other cardiovascular risk factors. However, among non-multivitamin supplement users, multivariable hazard ratios (95% confidence intervals) in the highest vs. lowest quintiles of VB(6) intake were 0.60 (0.37-0.97) for total coronary heart disease and 0.52 (0.29-0.91) for definite myocardial infarction, and the inverse associations with VB(12) were marginally significant. The combination of below-median intake of three vitamins or of only B(6) conferred a twice excess risk of total coronary heart disease. CONCLUSIONS: Dietary intake of VB(6) was associated with a reduced risk of coronary heart disease among middle-aged non-multivitamin supplement users. Dietary folate and VB(12) were also suggested to be protective factors for coronary heart disease.

Intake of fish and n3 fatty acids and risk of coronary heart disease among Japanese: the Japan Public Health Center-Based (JPHC) Study Cohort I.

BACKGROUND: Once- or twice-weekly consumption of fish (or a small amount of fish intake) reduces the risk of coronary heart disease and sudden cardiac death in Western countries. It is uncertain whether a high frequency or large amount of fish intake, as is the case in Japan, further reduces the risk. METHODS AND RESULTS: To examine an association between high intake of fish and n3 polyunsaturated fatty acids and the risk of coronary heart disease, a total of 41,578 Japanese men and women aged 40 to 59 years who were free of prior diagnosis of cardiovascular disease and cancer and who completed a food frequency questionnaire were followed up from 1990-1992 to 2001. After 477,325 person-years of follow-up, 258 incident cases of coronary heart disease (198 definite and 23 probable myocardial infarctions and 37 sudden cardiac deaths) were documented, comprising 196 nonfatal and 62 fatal coronary events. The multivariable hazard ratios (HRs) and 95% confidence intervals in the highest (8 times per week, or median intake=180 g/d) versus lowest (once a week, or median intake=23 g/d) quintiles of fish intake were 0.63 (0.38 to 1.04) for total coronary heart disease, 0.44 (0.24 to 0.81) for definite myocardial infarction, and 1.14 (0.36 to 3.63) for sudden cardiac death. The reduced risk was primarily observed for nonfatal coronary events (HR=0.43 [0.23 to 0.81]) but not for fatal coronary events (HR=1.08 [0.42 to 2.76]). Strong inverse associations existed between dietary intake of n3 fatty acids and risk of definite myocardial infarction (HR=0.35 [0.18 to 0.66]) and nonfatal coronary events (HR=0.33 [0.17 to 0.63]). CONCLUSIONS: Compared with a modest fish intake of once a week or &20 g/d, a higher intake was associated with substantially reduced risk of coronary heart disease, primarily nonfatal cardiac events, among middle-aged persons.

Validity of a self-administered food frequency questionnaire (FFQ) and its generalizability to the estimation of dietary folate intake in Japan.

BACKGROUND: In an epidemiological study, it is essential to test the validity of the food frequency questionnaire (FFQ) for its ability to estimate dietary intake. The objectives of our study were to 1) validate a FFQ for estimating folate intake, and to identify the foods that contribute to inter-individual variation of folate intake in the Japanese population. METHODS: Validity of the FFQ was evaluated using 28-day weighed dietary records (DRs) as gold standard in the two groups independently. In the group for which the FFQ was developed, validity was evaluated by Spearman's correlation coefficients (CCs), and linear regression analysis was used to identify foods with large inter-individual variation. The cumulative mean intake of these foods was compared with total intake estimated by the DR. The external validity of the FFQ and intake from foods on the same list were evaluated in the other group to verify generalizability. Subjects were a subsample from the Japan Public Health Center-based prospective Study who volunteered to participate in the FFQ validation study. RESULTS: CCs for the internal validity of the FFQ were 0.49 for men and 0.29 and women, while CCs for external validity were 0.33 for men and 0.42 for women. CCs for cumulative folate intake from 33 foods selected by regression analysis were also applicable to an external population. CONCLUSION: Our FFQ was valid for and generalizable to the estimation of folate intake. Foods identified as predictors of inter-individual variation in folate intake were also generalizable in Japanese populations. The FFQ with 138 foods was valid for the estimation of folate intake, while that with 33 foods might be useful for estimating inter-individual variation and ranking of individual folate intake.

Demographics, lifestyles, health characteristics, and dietary intake among dietary supplement users in Japan.

BACKGROUND: The associations between supplement use and certain demographics, lifestyles, health characteristics, and dietary intakes have not been studied in a large population in non-Western societies. The objective of our study was to investigate the association between supplement use and demographics, lifestyles, health characteristics, and dietary intake in a population-based cohort study in Japan. METHODS: Subjects were the 78 531 participants (45-74 years) who completed a self-administered questionnaire in 1995 or 1998 in a 5-year follow-up survey by the Japan Public Health Center-based prospective Study on cancer and cardiovascular disease. The questionnaire included enquiries about supplement use, occupation, height, weight, smoking, alcohol, physical activity, dietary behaviours, working hours, subjective stress, as well as intakes for 138 foods. RESULTS: The supplement users were likely to have formerly smoked or never smoked. Female supplement users were likely to consume alcohol moderately. The prevalence of users was higher in the elderly, the self-employed, those with lower body mass index, greater physical activity, lower frequency of eating prepared food, higher frequency of eating out, and higher stress level in both sexes after mutual adjustment. Mean intakes of energy and nutrients were lower for users than for non-users. CONCLUSION: The demographics, lifestyles, health characteristics, and dietary intakes may need to be adjusted when evaluating the effect of dietary supplements on disease because they can become potential confounding factors.

Self-administered food frequency questionnaire used in the 5-year follow-up survey of the JPHC Study: questionnaire structure, computation algorithms, and area-based mean intake.

In this section we described the structure of the self-administered semiquantitative food frequency questionnaire used in the 5-year follow-up survey of the JPHC study, the computation algorithms, and the area-based mean intakes of nutrients and food groups in the subjects of the validation study. The FFQ consists of five sections: 1) semiquantitative frequency questions for rice and miso (fermented soybean paste)-soup, 2) those for alcoholic beverages, 3) those for vitamin supplements, 4) those for foods and beverages, and 5) questions on dietary and cooking behaviors. From the questions, intakes of nutrients and foods by food groups were computed. Although most of them were computed from the frequency and relative portion size indicated in the replies, together with the fixed portion size, a seasonal coefficient was added in the computation of vegetables and fruits. Only frequency of intake and fixed portion size were used for computation of beverages. Sugar and cream added in coffee and tea were computed from the frequency of coffee and tea intake. The intakes of cooking oil, cooking salt (sodium), and salt in noodle-soup were estimated from the questions of relative preference of oil, salt, and noodle-soup.

Validity of a self-administered food frequency questionnaire used in the 5-year follow-up survey of the JPHC Study to assess selenium intake: comparison with dietary records and blood levels.

Selenium (Se) levels in serum and erythrocytes were measured in 215 adults to assess the relative validity of Se intake estimated from 28-day dietary records (DR) and the food frequency questionnaire (FFQ) used in the 5-year follow-up survey of the JPHC study. Se intake estimated from DR was correlated with that from the FFQ both in males and females (r=0.36 and r=0.32, respectively). Se levels in erythrocytes were weakly correlated with Se intake by DR for men (r=0.21) after adjustments for the total energy intake, though no significant correlation was found for women nor in crude values for either sex. Although Se intake estimated from our FFQ was correlated with that from the DR, no correlation was observed between the Se level in serum and estimated Se intake. In this population, the serum Se level was not a good biomarker for estimated Se intake.

Validity of the self-administered food frequency questionnaire used in the 5-year follow-up survey for the JPHC Study to assess folate, vitamin B6 and B12 intake: comparison with dietary records and blood level.

To validate a self-administered food frequency questionnaire (FFQ) for the estimation of dietary intake of folate, vitamins B6 and B12, we compared measures of these vitamins by the FFQ and plasma concentrations among 87 male volunteers aged 40-89 years in the Japan Public Health Center-based prospective study (JPHC Study). No men used folate, vitamins B6 or B12 as supplements. There was a moderate association between energy-adjusted dietary intake and plasma concentration for folate and vitamin B6. The Spearman correlation coefficient was 0.26 and 0.23, respectively, in the total samples. These correlation coefficients were slightly higher when men in the Ishikawa PHC area were excluded from the analysis; the correlation coefficient was 0.29 for folate and 0.26 for vitamin B6. No significant correlation was found between dietary vitamin B12 intake and serum B12 concentration; the correlation coefficient was 0.06 in the total sample and 0.15 when the Ishikawa men were excluded from the analysis. In conclusion, we found that the FFQ used for the 5-year follow-up survey of JPHC Study could reasonably rank individuals by dietary intake of folate and vitamin B6, but not vitamin B12, among Japanese community-dwelling population samples.