Acrylamide and Glycidamide Hemoglobin Adduct Levels and Breast Cancer Risk in Japanese Women: A Nested Case-Control Study in the JPHC.

BACKGROUND: Acrylamide (AA) is classified as "probably carcinogenic to humans (class 2A)" by the International Agency for Research on Cancer. AA causes cancer owing to its mutagenic and genotoxic metabolite, glycidamide (GA), and its effects on sex hormones. Both AA and GA can interact with hemoglobin to hemoglobin adducts (HbAA and HbGA, respectively), which are considered appropriate biomarkers of internal exposure of AA. However, few epidemiologic studies reported an association of HbAA and HbGA with breast cancer. METHODS: We conducted a nested case-control study within the Japan Public Health Center-based Prospective Study cohort (125 cases and 250 controls). Cases and controls were categorized into tertiles (lowest, middle, and highest) using the distribution of HbAA or HbGA levels in the control group and estimated ORs and 95% confidence intervals (CI) using conditional logistic regression, adjusting for potential confounders. RESULTS: No association was observed between HbAA (ORHighestvs.Lowest, 1.34; 95% CI, 0.69-2.59), HbGA (ORHighest vs. Lowest, 1.46; 95% CI, 0.79-2.69), their sum HbAA+HbGA (ORHighest vs. Lowest, 1.36; 95% CI, 0.72-2.58) and breast cancer; however, some evidence of positive association was observed between their ratio, HbGA/HbAA, and breast cancer (ORHighest vs. Lowest, 2.19; 95% CI, 1.11-4.31). CONCLUSIONS: There was no association between biomarkers of AA and breast cancer. IMPACT: It is unlikely that AA increases breast cancer risk; however, the association of AA with breast cancer may need to be evaluated, with a focus not only on the absolute amount of HbAA or HbGA but also on HbGA/HbAA and the activity of metabolic genes.

Validity of a food frequency questionnaire for the estimation of total polyphenol intake estimates and its major food sources in the Japanese population: the JPHC FFQ Validation Study.

We examine the validity and reproducibility of a food frequency questionnaire (FFQ) in a subsample of participants in the Japan Public Health Center-based Prospective Cohort Study using a database of polyphenol-containing foods commonly consumed in the Japanese population. Participants of the validation study were recruited from two different cohorts. In Cohort I, 215 participants completed a 28-d dietary record (DR) and the FFQ, and in Cohort II, 350 participants completed DRs and the FFQ. The total polyphenol intake estimated from the 28-d DR and FFQ were log-transformed and adjusted for energy intake by the residual method. Spearman correlation coefficients (CCs) between estimates from the FFQ and 28-d DR as well as two FFQs administered at a 1-year interval were computed. Median intakes of dietary polyphenols calculated from the DRs were 1172 mg/d for men and 1024 mg/d for women in Cohort I, and 1061 mg/d for men and 942 mg/d for women in Cohort II. The de-attenuated CCs for polyphenol intake between the DR and FFQ were 0⋅47 for men and 0⋅37 for women in Cohort I and 0⋅44 for men and 0⋅50 for women in Cohort II. Non-alcoholic beverages were the main contributor to total polyphenol intake in both men and women, accounting for 50 % of total polyphenol intake regardless of cohort and gender, followed by alcoholic beverages and seasoning and spices in men, and seasoning and spices, fruits and other vegetables in women. The present study showed that this FFQ had moderate validity and reproducibility and is suitable for use in future epidemiological studies.

Dietary Inflammatory Index Is Associated With Inflammation in Japanese Men.

Background: Dietary components are known to affect chronic low-grade inflammation status. The dietary inflammatory index (DII®) was developed to measure the potential impact of a diet on an individual's inflammatory status, and it has been validated mainly in Western countries. Objective: This study aimed to examine the validity of the energy-adjusted DII (E-DIITM) using high-sensitivity C-reactive protein (hs-CRP) concentration in Japanese men and women. Methods: In total, 6,474 volunteers from a cancer-screening program (3,825 men and 2,649 women) completed a food frequency questionnaire (FFQ) and their hs-CRP concentrations were evaluated. E-DII scores were calculated on the basis of 30 food parameters derived from the FFQ. Higher E-DII scores reflect a greater pro-inflammatory potential of the diet. The associations between E-DII quartiles and hs-CRP concentration were assessed using regression models adjusted for age, body mass index, smoking status, and amount of physical activity. Results: Mean E-DII in men and women was + 0.62 ± 1.93 and -1.01 ± 2.25, respectively. The proportion of men and women who had hs-CRP concentration >3 mg/L was 4.7 and 3.1%, respectively. A significant positive association was observed between E-DII score and hs-CRP concentration in men; geometric mean of hs-CRP concentration in the lowest and highest E-DII quartiles was 0.56 mg/L and 0.67 mg/L (P trend < 0.01), respectively. The odds ratio (95% confidence interval) of having an elevated hs-CRP concentration (>3 mg/L) was 1.72 (1.10-2.67) in the highest E-DII quartile (P trend = 0.03) in men. However, no association was observed between E-DII score and hs-CRP concentration in women, except in those not taking prescription medications. Conclusions: DII was associated with inflammation status in Japanese men, but the association was limited in Japanese women.

Dietary Acrylamide Intake and the Risks of Renal Cell, Prostate, and Bladder Cancers: A Japan Public Health Center-Based Prospective Study.

Acrylamide can be carcinogenic to humans. However, the association between the acrylamide and the risks of renal cell, prostate, and bladder cancers in Asians has not been assessed. We aimed to investigate this association in the Japan Public Health Center-based Prospective Study data in 88,818 Japanese people (41,534 men and 47,284 women) who completed a food frequency questionnaire in the five-year follow-up survey in 1995 and 1998. A validated food frequency questionnaire was used to assess the dietary acrylamide intake. Cox proportional hazard regression models were used to estimate hazard ratios and 95% confidence intervals (CIs). During a mean follow-up of 15.5 years (15.2 years of prostate cancer), 208 renal cell cancers, 1195 prostate cancers, and 392 bladder cancers were diagnosed. Compared to the lowest quintile of acrylamide intake, the multivariate hazard ratios for the highest quintile were 0.71 (95% CI: 0.38-1.34, p for trend = 0.294), 0.96 (95% CI: 0.75-1.22, p for trend = 0.726), and 0.87 (95% CI: 0.59-1.29, p for trend = 0.491) for renal cell, prostate, and bladder cancers, respectively, in the multivariate-adjusted model. No significant associations were observed in the stratified analyses based on smoking. Dietary acrylamide intake was not associated with the risk of renal cell, prostate, and bladder cancers.

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

Acrylamide, which is present in many daily foods, is a probable human carcinogen. In 2002, it was identified in several common foods. Subsequently, western epidemiologists began to explore the relationship between dietary acrylamide exposure and cancer risk; however, limited suggestive associations were found. This prospective study aimed to examine the association between dietary acrylamide intake and the risk of hematological malignancies, including malignant lymphoma (ML), multiple myeloma (MM), and leukemia. We enrolled 85,303 participants in the Japan Public Health Center-based Prospective study on diet and cancer as from 1995. A food frequency questionnaire that included data on acrylamide in all Japanese foods was used to assess dietary acrylamide intake. We applied multivariable adjusted Cox proportional hazards models to reckon hazard ratios (HRs) for acrylamide intake for both categorical variables (tertiles) and continuous variables. After 16.0 median years of follow-up, 326 confirmed cases of ML, 126 cases of MM, and 224 cases of leukemia were available for final multivariable-adjusted analysis. HRs were 0.87 (95% confidence interval [CI]: 0.64-1.18) for ML, 0.64 (95% CI: 0.38-1.05) for MM, and 1.01 (95% CI: 0.71-1.45) for leukemia. Our results implied that acrylamide may not be related to the risk of hematological malignancies.

Acrylamide-Hemoglobin Adduct Levels in a Japanese Population and Comparison with Acrylamide Exposure Assessed by the Duplicated Method or a Food Frequency Questionnaire.

The levels of hemoglobin adducts of acrylamide (AA-Hb), a biomarker of acrylamide exposure, have not been reported for Japanese subjects. Herein, we determined the AA-Hb levels in a Japanese population and compared them with the estimated dietary intake from the duplicate diet method (DM) and a food frequency questionnaire (FFQ). One-day DM samples, FFQ, and blood samples were collected from 89 participants and analyzed for acrylamide. AA-Hb was analyzed using liquid chromatography tandem mass spectrometry and the N-alkyl Edman method. Participants were divided into tertiles of estimated acrylamide intake and geometric means (GMs) of AA-Hb adjusted for sex and smoking status. A stratified analysis according to smoking status was also performed. The average AA-Hb levels for all participants, never, past, and current smokers were 46, 38, 65, and 86 pmol/g Hb, respectively. GMs of AA-Hb levels in all participants were significantly associated with tertiles of estimated acrylamide intake from DM (p for trend = 0.02) and FFQ (p for trend = 0.04), although no association with smokers was observed. AA-Hb levels reflected smoking status, which were similar to values reported in Western populations, and they were associated with estimated dietary intake of acrylamide when adjusted for sex and smoking status.

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 Risk of Lung Cancer: The Japan Public Health Center Based Prospective Study.

Acrylamide, which forms in heat-treated foods with high carbohydrate content, is a probable human carcinogen. This study aimed to evaluate the association between dietary acrylamide intake and lung cancer using data from the Japan Public Health Center based Prospective Study. Our study included 85,303 participants who completed a food frequency questionnaire. Cox proportional hazards regression models were used to assess hazard ratios and 95% confidence intervals (CIs) after adjusting for confounders. After 14.3 years and 15.4 years of mean follow-up period, 1187 and 485 lung cancer cases were identified in men and women, respectively. The multivariable-adjusted hazard ratios of 10-µg/day increment in acrylamide intake were 1.01 (95% CI, 0.99-1.02) in men and 0.98 (95% CI, 0.95-1.02) in women. Compared with the lowest quartile of acrylamide intake, the hazard ratios for the highest quartile were 1.13 (95% CI, 0.95-1.33; p for trend = 0.12) in men and 1.03 (95% CI, 0.78-1.36; p for trend = 0.86) in women in the multivariable-adjusted model. Moreover, there was also no significant association observed in the stratified analysis for histological subtypes of lung cancer. This study demonstrated that dietary acrylamide intake was not associated with increased lung cancer risk in the Japanese population.

Variations in the estimated intake of acrylamide from food in the Japanese population.

BACKGROUND: Due to concerns of carcinogenicity, it is necessary to assess long-term acrylamide exposure in individuals. Whether the available methods of estimating acrylamide intake can indicate long-term exposure remains unknown. We examined variations in the estimated dietary acrylamide intake of the Japanese population. METHODS: The study included 240 participants aged 40-74 years who were a part of the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT). Twelve-day dietary records (DRs) were collected over a one-year period, and food frequency questionnaires (FFQs) were collected twice during the year. Dietary acrylamide intake was estimated from an acrylamide content database. Within-individual variations and between-individual variations were calculated using the random effects model. A linear regression analysis was performed to identify foods with large between-individual variations. RESULTS: The ratios of within-individual variance to between-individual variation were 3.2 for men and 4.3 for women. Days of DRs required to estimate the usual individual intake within 20% of the true mean intake with 95% confidence were 60 days for men and 66 days for women. Coffee/cocoa, potato, and green tea contributed to between-individual variations, in that order, and seven foods contributed to 93% of the between-individual variation. CONCLUSIONS: Estimating the acrylamide intake using DRs requires an extended data collection period to estimate the intragroup ranking and habitual intake of individuals. Long-term exposure assessments should be based on methods with less potential for measurement errors, such as the use of biomarkers.

Validating the dietary inflammatory index using inflammatory biomarkers in a Japanese population: A cross-sectional study of the JPHC-FFQ validation study.

OBJECTIVES: Persistent low-grade inflammation is related to the development of many chronic diseases. The dietary inflammatory index (DII®) is designed to assess the potential effects of diet on an individual's inflammation status. The aim of this study was to evaluate the construct validity of the DII using inflammation biomarkers in Japanese adults. METHODS: Overall, 565 participants from the food frequency questionnaire (FFQ) validation study of the Japan Public Health Center-Based Prospective Cohort were included in the present study. This cohort consisted of two independently recruited and examined, cohorts I and II. Dietary records (DR) were collected for 28 d and two FFQs were administered. Blood samples also were obtained for the analysis of high-sensitivity C-reactive protein (hs-CRP) and interleukin (IL)-6 concentrations. DII scores were calculated from DR and FFQ using energy-adjusted dietary intakes by the density method. Higher DII scores indicate a greater proinflammatory potential of the diet. The associations between DII and inflammatory biomarkers were assessed using regression models adjusted for age, body mass index, smoking status, and amount of physical activity. RESULTS: The associations between DR- and FFQ-derived DII scores were moderate. Higher DR-derived DII scores, representing a more proinflammatory diet, were significantly correlated with IL-6, but not hs-CRP, concentrations in men. The geometric means of IL-6 concentrations in the lowest and highest DII quartiles were 1.05 and 1.33 pg/mL (P = 0.02 for trend) in cohort I, and 1.00 and 1.24 pg/mL (P = 0.03 for trend) in cohort II, respectively. Furthermore, IL-6 concentration appeared to increase across DII quartiles calculated from FFQ in men. However, there was no association between DII and inflammatory biomarkers in women. CONCLUSIONS: Null findings in women may reflect the generally lower levels of chronic systemic inflammation among Japanese versus their Western counterparts. These findings indicate that DII may be applied to measure the potential effects of diet on chronic diseases through inflammatory pathways in Japanese men.

Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality in a Japanese Cohort.

Importance: Epidemiological evidence regarding the long-term effects of higher dietary protein intake on mortality outcomes in the general population is not clear. Objective: To evaluate the associations between animal and plant protein intake and all-cause and cause-specific mortality. Design, Setting, and Participants: This prospective cohort study included 70 696 participants in the Japan Public Health Center-based Prospective Cohort who were aged 45 to 74 years and had no history of cancer, cerebrovascular disease, or ischemic heart disease at study baseline. Data were collected from January 1, 1995, through December 31, 1999, with follow-up completed December 31, 2016, during which 12 381 total deaths were documented. Dietary intake information was collected through a validated food frequency questionnaire and used to estimate protein intake in all participants. Participants were grouped into quintile categories based on their protein intake, expressed as a percentage of total energy. Data were analyzed from July 18, 2017, through April 10, 2019. Main Outcomes and Measures: Hazard ratios (HRs) and 95% CIs for all-cause and cause-specific mortality were estimated using Cox proportional hazards regression models with adjustment for potential confounding factors. Results: Among the 70 696 participants, 32 201 (45.5%) were men (mean [SD] age, 55.6 [7.6] years) and 38 495 (54.5%) were women (mean [SD] age, 55.8 [7.7] years). Intake of animal protein showed no clear association with total or cause-specific mortality. In contrast, intake of plant protein was associated with lower total mortality, with multivariable-adjusted HRs of 0.89 (95% CI, 0.83-0.95) for quintile 2; 0.88 (95% CI, 0.82-0.95) for quintile 3; 0.84 (95% CI, 0.77-0.92) for quintile 4; and 0.87 (95% CI, 0.78-0.96) for quintile 5, with quintile 1 as the reference category (P = .01 for trend). For cause-specific mortality, this association with plant protein intake was evident for cardiovascular disease (CVD)-related mortality (HRs, 0.84 [95% CI, 0.73-0.96] to 0.70 [95% CI, 0.59-0.83]; P = .002 for trend). Isocaloric substitution of 3% energy from plant protein for red meat protein was associated with lower total (HR, 0.66; 95% CI, 0.55-0.80), cancer-related (HR, 0.61; 95% CI, 0.45-0.82), and CVD-related (HR, 0.58; 95% CI, 0.39-0.86) mortality; substitution for processed meat protein was associated with lower total (HR, 0.54; 95% CI, 0.38-0.75) and cancer-related (HR, 0.50; 95% CI, 0.30-0.85) mortality. Conclusions and Relevance: In this large prospective study, higher plant protein intake was associated with lower total and CVD-related mortality. Although animal protein intake was not associated with mortality outcomes, replacement of red meat protein or processed meat protein with plant protein was associated with lower total, cancer-related, and CVD-related mortality.

Higher Dietary Non-enzymatic Antioxidant Capacity Is Associated with Decreased Risk of All-Cause and Cardiovascular Disease Mortality in Japanese Adults.

BACKGROUND: Few studies have assessed associations of non-enzymatic antioxidant capacity (NEAC) in the overall diet with all-cause or specific mortality, and their results have been inconsistent. OBJECTIVES: The present study investigated the association between dietary NEAC and all-cause or cause-specific mortality. METHODS: The study was a large-scale population-based prospective cohort study in Japan consisting of 42,520 men and 50,207 women aged 44-76 y, who had no history of cancer, stroke, ischemic heart disease, or chronic liver disease. We evaluated FFQ-based dietary NEAC with use of published databases in which the NEACs of individual foods were analyzed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Dietary NEAC was calculated by multiplying the estimated NEAC with the consumed amount and summing up those values for all foods, and was categorized in quartiles. We identified death and cause of death with use of residential registry and death certificates. HRs and 95% Cls for death from the second survey, which was conducted from April 1995 to December 2014 were estimated with Cox proportional hazards regression analysis. RESULTS: After 1,498,308 person-years of follow-up, 12,978 total deaths occurred. The multivariable-adjusted HRs (95% Cls) for all-cause mortality for the highest compared with the lowest quartile of FRAP and ORAC were 0.85 (0.80, 0.89) and 0.84 (0.79, 0.89), respectively. Dietary NEACs were inversely associated with mortality from cardiovascular disease (CVD), but not from cancer. The multivariable-adjusted HRs (95% Cls) for CVD for the highest compared with the lowest quartile of FRAP and ORAC were 0.83 (0.75, 0.92) and 0.79 (0.70, 0.89), respectively. CONCLUSIONS: Higher dietary NEACs from FRAP and ORAC were associated with lower risk of all-cause mortality and mortality from CVD in Japanese adults.

Relationship between dietary non-enzymatic antioxidant capacity and type 2 diabetes risk in the Japan Public Health Center-based Prospective Study.

OBJECTIVE: Intake of antioxidants may reduce the risk for type 2 diabetes (T2D) by reducing oxidative stress. However, it is unclear whether dietary non-enzymatic antioxidant capacity (NEAC), which represents the cumulative action of dietary antioxidants and their synergistic effects in foods, is associated with decreased T2D risk. The aim of this study was to investigate the associations between dietary NEAC and T2D. METHODS: The study included 64 660 adults (27 809 men and 36 851 women), 44 to 76 y of age without history of T2D in the Japan Public Health Center-based Prospective Study. Dietary NEAC was estimated using databases of NEAC measurements compiled from results for three different assays: ferric reducing-antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and total radical-trapping antioxidant parameter (TRAP). A multiple logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of self-reported physician-diagnosed T2D over 5 y with adjustment for potential confounders. RESULTS: In all, 1191 cases of newly diagnosed T2D were reported. Dietary NEACs were not significantly associated with T2D. The multivariate-adjusted ORs were 1.04 (95% CI, 0.88-1.23; Ptrend = 0.56) for FRAP, 1.11 (95% CI, 0.93-1.32; Ptrend = 0.26) for ORAC, and 0.99 (95% CI, 0.84-1.18; Ptrend = 0.84) for TRAP. Similar associations were observed in men and women (Pinteraction = 0.46 for FRAP, 0.35 for ORAC, and 0.63 for TRAP). In stratified analyses of major prooxidant factors, no notable associations with smoking and obesity status were observed. CONCLUSIONS: This finding suggests that dietary NEAC may not be appreciably associated with T2D in Japanese adults.

Dietary Acrylamide Intake and Risk of Esophageal, Gastric, and Colorectal Cancer: The Japan Public Health Center-Based Prospective Study.

BACKGROUND: Acrylamide has been classified as a probable human carcinogen based chiefly on laboratory evidence. However, the influence of dietary acrylamide intake on risk of esophageal, gastric, and colorectal cancer has not been extensively studied. We aimed to evaluate the association between dietary acrylamide intake and esophageal, gastric, and colorectal cancer using data from the Japan Public Health Center-based Prospective Study. METHODS: Our study included 87,628 participants who completed a food-frequency questionnaire at enrollment in 1990 and 1993. We used Cox proportional hazards regression models to estimate hazards ratios and 95% confidence intervals (CI) after adjusting for confounding factors. RESULTS: After 15.5, 15.3, and 15.3 mean years of follow-up for esophageal, gastric, and colorectal cancer, we identified and analyzed 391 esophageal, 2,218 gastric, and 2,470 colorectal cancer cases, respectively. Compared with the lowest quintile of acrylamide intake, the multivariate HR for the highest quintile was 0.86 (95% CI, 0.53-1.39; P trend = 0.814), 0.84 (95% CI, 0.69-1.01; P trend = 0.301), and 0.93 (95% CI, 0.79-1.08; P trend = 0.165) for esophageal, gastric, and colorectal cancer, respectively, in the multivariable-adjusted model. Furthermore, no significant associations were observed when the participants were stratified by cancer subsites. CONCLUSIONS: In conclusion, this study demonstrated that dietary acrylamide intake was not associated with increased risk of esophageal, gastric, or colorectal cancer among the Japanese population. IMPACT: It is the first time to assess the effect of dietary acrylamide intake on risk of digestive system cancer in Asian populations.

Validity of Estimated Acrylamide Intake by the Dietary Record Method and Food Frequency Questionnaire in Comparison with a Duplicate Method: A Pilot Study.

Acrylamide, classified as a probable carcinogen to humans, forms during high- temperature cooking. Dietary exposure among the Japanese is unknown. To evaluate the validity of estimated acrylamide intake using a dietary record (DR) and the food frequency questionnaire (FFQ) in comparison with the duplicate diet method (DM) in a Japanese population. Design: A validation study was performed with 14 participants (age, 32-50 y; 11 women) from 11 households. Food samples were simultaneously collected for the DM and DR on the same day over 2 consecutive days. The FFQ was administered after collecting samples for the DM and DR. For the DM, dietary acrylamide was calculated from chemical analyses of each food. For the DR and FFQ, acrylamide intake for each food was calculated using the database of acrylamide contents of foods. Correlation coefficients were calculated using the Spearman rank method. Average acrylamide intake values calculated using the DM, DR, and FFQ were 0.106, 0.233, and 0.128 µg/kg body weight/d, respectively; these values showed a marginally positive correlation between the DM and DR (r=0.52), but a low correlation between the DM and FFQ (r=-0.011). For the DR, non-alcoholic drinks had the highest contribution, followed by confectionery and vegetables. For the DM, the contribution of confectionery was the highest, followed by vegetables and non-alcoholic drinks. In conclusion, the validity of acrylamide intake estimation using the DR was reasonably high when compared to the analytical value of the simultaneous DM. However, further improvement is required for estimating acrylamide intake using the FFQ.

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.

Validity of a Self-administered Food Frequency Questionnaire for the Estimation of Acrylamide Intake in the Japanese Population: The JPHC FFQ Validation Study.

BACKGROUND: Acrylamide, a probable carcinogen to humans, forms during high temperature cooking. Dietary exposure to acrylamide among the Japanese population is unknown. We aimed to establish and validate a method to assess acrylamide exposure among the Japanese population using a food frequency questionnaire (FFQ) from the Japan Public Health Center-based prospective study. METHODS: Validation studies for the FFQ were conducted in 1994 (Cohort I, n = 215) and 1996 (Cohort II, n = 350). The 28-day dietary records (DRs) were collected over 1 year. The FFQ was distributed before and after DR collection. Data for acrylamide exposure were based on reported measurements in Japan, and calculations considered the cooking process for specific vegetables in a home setting. Spearman's rank correlation and weighted kappa coefficients were calculated from energy-adjusted data. RESULTS: Mean acrylamide intake levels estimated from DRs for Cohorts I and II were 6.78 (standard deviation [SD], 3.89) µg/day and 7.25 (SD, 3.33) µg/day, and corresponding levels estimated from the FFQ were 7.03 (SD, 4.30) µg/day and 7.14 (SD, 3.38) µg/day, respectively. Deattenuated correlation coefficients for men and women were 0.54 and 0.48 in Cohort I and 0.40 and 0.37 in Cohort II, respectively. Weighted kappa coefficients were over 0.80 in all cases. The main contributing food groups from DRs were beverages, confectioneries, vegetables, potatoes and starches, and cereals. CONCLUSIONS: High kappa values validate the use of FFQ in epidemiological studies. The marked contribution of cooked vegetables indicates the importance of considering household cooking methods in assessing acrylamide intake levels in the Japanese population.

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.

Dietary acrylamide intake and risk of breast cancer: The Japan Public Health Center-based Prospective Study.

Acrylamide forms during cooking and is classified as a probable carcinogen in humans, mandating the need for epidemiological studies of dietary acrylamide and cancers. However, the risk of dietary acrylamide exposure to breast cancer in Japanese women has not been assessed. We investigated the association between dietary acrylamide intake and risk of breast cancer in the Japan Public Health Center-based Prospective Study. The present study included 48 910 women aged 45-74 years who responded to a 5-year follow-up survey questionnaire. Dietary acrylamide intake was assessed using a validated food frequency questionnaire. Cox proportional hazards regression models were used to estimate hazard ratios and 95% confidence intervals. During an average of 15.4 years of follow up, 792 breast cancers were diagnosed. Energy-adjusted dietary acrylamide intake was not associated with the risk of breast cancer (adjusted hazard ratio for highest versus lowest tertile = .95, 95% confidence intervals: 0.79-1.14, P-trend = .58). Further, no significant associations were observed when stratified analyses were conducted by smoking status, coffee consumption, alcohol consumption, body mass index, menopausal status, estrogen receptor status, and progesterone receptor status. In conclusion, dietary acrylamide intake was not associated with the risk of breast cancer in this population-based prospective cohort study of Japanese women.