Association of normal weight obesity with lifestyle and dietary habits in young Thai women: A cross-sectional study.

Background: The risk of lifestyle-related diseases in normal weight obesity (NWO), a condition, in which the body mass index (BMI) is normal but the body fat mass is high, has attracted a lot of attention. However, there are no reports on the association between NWO and lifestyle, eating habits, and other health risks in Thai people. BMI alone cannot be used to identify individuals with NWO; thus, some students with NWO develop metabolic abnormalities without receiving any intervention. This study aimed to examine the differences in anthropometrics, lifestyle, and eating habits among young Thai women and their association with the BMI and the body fat ratio (BFR). Methods: A total of 250 female Thai university students of normal body type (18.5 ≤ BMI<25.0 kg/m2) were classified as having non-normal weight obesity (NO-NWO) if their BFR was <30.0% or NWO if their BMI and BFR were >30.0%. The lifestyle and eating habits of the two groups were compared. We conducted logistic analysis with the presence or absence of NWO as the dependent variable, and the dietary habit items of "eating greasy foods," "eating ultra-processed foods (UPF)," and "drinking sweetened beverages" as the objective variables. Results: Among the study participants who were of normal body type, 46.8% were NWO. The participants in the NWO group consumed UPF more frequently (odds ratio [OR], 2.04; p = 0.014) and sweetened beverages more regularly (OR, 1.92, p = 0.041) than those in the NO-NWO group. Conclusion: UPF and sweetened beverage consumption was more common in individuals with NWO. Identifying the risk factors for NWO is essential to help individuals make lifestyle changes to prevent its progression and complications.

The Association Between Eating Quickly and Excessive Gestational Weight Gain.

Objectives: Maintaining an appropriate gestational weight gain (GWG) is essential for a safe pregnancy and delivery. This study aimed to determine the association between the habit of eating quickly and the risk of excessive GWG. Methods: We administered a questionnaire on eating habits to 1246 pregnant Japanese women in their second to third trimesters. We categorized the participants into three groups according to their answers to the question "Do you eat quickly?" Group 1, "always" or "usually"; Group 2, "sometimes"; and Group 3, "rarely" or "never." We assessed GWG according to the "The Optimal Weight Gain Chart" (Ministry of Health, Labor and Welfare, Japan), and those who exceeded the criteria were considered "excessive." Logistic regression analysis was performed with the risk of excess GWG as the dependent variable and quick food intake as the independent variable, to obtain relevant odds ratios (ORs) and 95% confidence intervals (CIs). Model 1 was unadjusted, and Model 2 was adjusted for age, prepregnancy body mass index, energy intake, mother's educational attainment, household income, exercise habits, and childbearing experience. Results: The OR (95% CI) for Groups 2 and 3 in Model 1, compared with Group 1, was 0.80 (0.62-1.05) and 0.61 (0.43-0.88), respectively (p for trend = 0.047). In Model 2, the OR (95% CI) for Groups 2 and 3 were 0.73 (0.55-0.96) and 0.59 (0.40-0.86), respectively (p for trend = 0.003). Conclusion: These results suggest that quick food ingestion increases the risk of excessive GWG.

Relationship between Maternal Mood Disorders and Dietary Intake of 3-Year-Olds.

Maternal depression affects parenting and children's early development, but its effect on dietary intake is unknown. While husbands' involvement in parenting and having friends to talk to may reduce childcare stress, this has not been thoroughly studied. In this study, mothers were stratified by the presence or absence of mood disorders, and the effects of support from their husbands and friends on the dietary intake of their 3-year-old children were examined. This cross-sectional analysis included 920 mother-child pairs examined at the National Center for Child Health and Development in Japan. Dietary intake was assessed using a brief dietary history questionnaire, and physical measurements were taken when the children were 3 years old. The Kessler Psychological Distress Scale was used to screen for maternal mood disorders, 3 years after delivery. The presence or absence of the husband's assistance with housework and childcare, mental support, and friends was obtained from a self-administered questionnaire when the child was 3 years old. Differences in the children's physical measurements, energy, and food intake with the presence or absence of support for subjects with or without mood disorders were compared. Mothers with support from husbands or friends had significantly fewer mood disorders. Support from friends and family did not affect the children's physical development and whether or not mothers had mood disorder symptoms. However, children's vegetable intake was higher if mothers were supported. Children of mothers with mood disorders had a significantly higher vegetable intake and fruit intake, depending on the support from friends (P=0.046, P=0.037); thus, such support may increase children's vegetable and fruit intake. The results of this study revealed the importance of supportive friends and family regarding childcare.

Association of dietary diversity with total mortality and major causes of mortality in the Japanese population: JPHC study.

BACKGROUND/OBJECTIVES: Eating a variety of foods has been recommended in the dietary guidelines of many developed nations, as well as global dietary guidelines. We investigated the potential effect of dietary diversity on the risk of total mortality and major causes of mortality in a large-scale cohort study involving the Japanese population. SUBJECTS/METHODS: From 1995 to 2012, 79,904 participants (37,240 men and 42,664 women) aged 45 to 74 years, without histories of ischemic heart disease, stroke, or cancer were followed-up for a median of 14.9 years. We used 133 food and beverage items listed on a 5-year follow-up food frequency questionnaire, and the daily frequency of consumption for each item (excluding five alcoholic beverages) was counted. Multivariable-adjusted Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) to compare the highest and lowest quintiles. RESULTS: An inverse association was identified between total dietary diversity and mortality rates in women (highest quintile HR: 0.81; 95% CI: 0.71, 0.92; p for trend = 0.002) but the same trend was not observed in men (highest quintile HR: 0.96; 95% CI: 0.87, 1.10; p for trend = 0.266). In addition, fruit diversity was associated with lower mortality rates in men (highest quintile HR: 0.87; 95% CI: 0.79, 0.95; p for trend = 0.006), whereas soy diversity was associated with lower mortality rates in women (highest quintile HR: 0.89; 95% CI: 0.79, 1.00; p for trend = 0.004). With regard to men, meat and fish diversity were associated with higher mortality rates (highest quintiles of meat and fish diversity HR: 1.15 [95% CI: 1.06, 1.25] and 1.12 [95% CI: 1.02, 1.22], respectively). CONCLUSIONS: These findings indicate that consuming a greater diversity of total foods and increasing the diversity of fruit and soy consumed have considerable public health implications.

Maternal vegetable intake in early pregnancy and wheeze in offspring at the age of 2 years.

BACKGROUND/OBJECTIVES: Vegetable intake during childhood may reduce the risk of subsequent asthma. We verified the effect of maternal intake during pregnancy on asthma risk in offspring, which has rarely been studied. SUBJECTS/METHODS: In a hospital-based birth cohort study conducted in Tokyo, we administered a food frequency questionnaire at two periods during the respondents' pregnancy: early and mid to late periods. In addition, a questionnaire including the International Study of Asthma and Allergies in Childhood questionnaire was conducted when the offspring were 2 years old. Multivariate Poisson regression adjusting for maternal baseline demographics was used to elucidate the association between maternal vegetable intake and the incidence of wheeze in the offspring. RESULTS: Among 310 singletons, 82 (26.5%) experienced wheeze at 2 years of age. Women with the highest intake of cruciferous, and folate-rich vegetables during early pregnancy reported a significantly lower prevalence of wheeze in their child at 2 years of age in comparison with those who reported the lowest intake (adjusted risk ratio: 0.48 and 0.47, 95% confidence interval: 0.26-0.89, and 0.25-0.87, respectively). In trend analysis, a higher maternal intake of cruciferous, folate-rich vegetables, and total vegetables during early pregnancy was less likely to be associated with wheeze in the offspring at 2 years old (p for trend: 0.038, <0.001, and 0.028, respectively). Maternal vegetable intake during mid to late pregnancy was not associated with wheeze in the offspring. CONCLUSIONS: Maternal vegetable intake during early pregnancy may have a protective effect against asthma in offspring at 2 years of age.

Dietary n-3 Polyunsaturated Fatty Acids in Late Pregnancy and Postpartum Depressive Symptom among Japanese Women.

BACKGROUND: The use of n-3 polyunsaturated fatty acids (n-3PUFA) in preventive or therapeutic modalities for postpartum depression, especially long-chain types such as eicosapentaenoic acid (EPA) and a docosahexaenoic acid (DHA), is of considerable interest. High n-3PUFA consumption has been reported among pregnant Japanese women. Therefore, analysis of this group could provide important insights into the relationship between postpartum depression and dietary n-3PUFA consumption. To further examine the relationship between the risk of postpartum depression and n-3PUFA consumption, we conducted a prospective hospital-based birth cohort study in Japan. DESIGN AND METHODS: Our prospective birth cohort study was performed at the National Center for Child Health and Development (NCCHD) in suburban Tokyo, Japan. Dietary n-3PUFA intake during late pregnancy was assessed by a semi-quantitative food questionnaire and participants were categorized by quintile distributions of n-3PUFA intake. A Japanese translation of the Edinburgh Postnatal Depression Scale was used to screen women for postpartum depression at 1 month after delivery (967 women) and at 6 months after delivery (710 women). We performed logistic regression analysis to examine the relationship between the risk of postpartum depression and n-3PUFA consumption after adjusting for confounding factors. RESULTS: Significant associations between EPA, DHA, and n-3PUFA intakes in late pregnancy and postpartum depression at both 1 and 6 months after delivery were not observed. CONCLUSION: This prospective study indicated that EPA, DHA, and n-3PUFA intake during late pregnancy was not associated with the risk of postpartum depression.

Validation of a food frequency questionnaire for Japanese pregnant women with and without nausea and vomiting in early pregnancy.

BACKGROUND: No previous study has shown the validity of a food frequency questionnaire (FFQ) in early pregnancy with consideration of nausea and vomiting during pregnancy (NVP). The aim of this study was to evaluate the validity of a FFQ in early pregnancy for Japanese pregnant women. METHOD: We included 188 women before 15 weeks of gestation and compared estimated nutrient intake and food group intake based on a modified FFQ with that based on 3-day dietary records (DRs). Spearman's rank correlation coefficients, adjusting energy intake and attenuating within-person error, were calculated. Subgroup analysis for those with and without NVP was conducted. We also examined the degree of appropriate classification across categories between FFQ and DRs through division of consumption of nutrients and food groups into quintiles. RESULTS: Crude Spearman's correlation coefficients of nutrients ranged from 0.098 (sodium) to 0.401 (vitamin C), and all of the 36 nutrients were statistically significant. In 27 food groups, correlation coefficients ranged from -0.015 (alcohol) to 0.572 (yogurt), and 81% were statistically significant. In subgroup analysis, correlation coefficients in 89% of nutrients and 70% of food groups in women with NVP and 97% of nutrients and 74% of food groups in women without NVP were statistically significant. On average, 63.7% of nutrients and 60.4% of food groups were classified into same or adjacent quintiles according to the FFQ and DRs. CONCLUSIONS: The FFQ is a useful instrument, regardless of NVP, for assessing the diet of women in early pregnancy in Japan.

Validity of a food frequency questionnaire to estimate long-chain polyunsaturated fatty acid intake among Japanese women in early and late pregnancy.

BACKGROUND: The relative validity of food frequency questionnaires for estimating long-chain polyunsaturated fatty acid (LC-PUFA) intake among pregnant Japanese women is currently unclear. The aim of this study was to verify the external validity of a food frequency questionnaire, originally developed for non-pregnant adults, to assess the dietary intake of LC-PUFA using dietary records and serum phospholipid levels among Japanese women in early and late pregnancy. METHODS: A validation study involving 188 participants in early pregnancy and 169 participants in late pregnancy was conducted. Intake LC-PUFA was estimated using a food frequency questionnaire and evaluated using a 3-day dietary record and serum phospholipid concentrations in both early and late pregnancy. RESULTS: The food frequency questionnaire provided estimates of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake with higher precision than dietary records in both early and late pregnancy. Significant correlations were observed for LC-PUFA intake estimated using dietary records in both early and late pregnancy, particularly for EPA and DHA (correlation coefficients ranged from 0.34 to 0.40, p < 0.0001). Similarly, high correlations for EPA and DHA in serum phospholipid composition were also observed in both early and late pregnancy (correlation coefficients ranged 0.27 to 0.34, p < 0.0001). CONCLUSIONS: Our findings suggest that the food frequency questionnaire, which was originally designed for non-pregnant adults and was evaluated in this study against dietary records and biological markers, has good validity for assessing LC-PUFA intake, especially EPA and DHA intake, among Japanese women in early and late pregnancy.

Validation of a food-frequency questionnaire for assessing vitamin intake of Japanese women in early and late pregnancy with and without nausea and vomiting.

Maternal vitamin intake during pregnancy is crucial for pregnancy outcomes and the child's subsequent health. However, there are few valid instruments for assessing vitamin intake that address the effects of nausea and vomiting during pregnancy (NVP). This study aimed to investigate the validity of a FFQ concerning vitamin intake during early and late pregnancy with and without NVP. The participants comprised 200 Japanese pregnant women who completed the FFQ and from whom blood samples were taken in early and late pregnancy. Energy-adjusted dietary vitamin intakes (vitamin C, folate, vitamin B6, vitamin B12, vitamin A, vitamin E and vitamin D) from FFQ were compared with their blood concentrations. A subgroup of women with NVP was investigated. In early pregnancy, significant correlations between FFQ and biomarkers were observed for vitamin C (r 0·27), folate (r 0·18) and vitamin D (r 0·26) in women with NVP and for vitamin A (r 0·18), vitamin B12 (r 0·24) and vitamin D (r 0·23) in women without NVP. No significant correlations were observed in either group for vitamins B6 or E. In late pregnancy, similar significant associations were observed for vitamin C (r 0·27), folate (r 0·22), vitamin B6 (r 0·18), vitamin B12 (r 0·27) and vitamin A (r 0·15); coefficients were higher among women without NVP. Our study demonstrates that the FFQ is a useful tool for assessing intake of several important vitamins in early and late pregnancy regardless of NVP status.

Relationship between environmental exposure to cadmium and bone metabolism in a non-polluted area of Japan.

OBJECTIVES: The purpose of this study was to investigate the effects of environmental low-grade cadmium exposure on bone in the population of a non-polluted area. We investigated the relationship between environmental cadmium exposure (via rice intake) and bone metabolism in middle-aged and elderly women living in a non-polluted area in Japan. METHODS: Four hundred and twenty-nine women over the age of 39 years (54.6 ± 9.1 years; arithmetic mean ± SD) participated in this study in 2003. We investigated blood and urine, and rice intake, and performed ultrasonic bone evaluation, and obtained individual information about the subjects' health. Multiple regression analysis was performed in the statistical analysis. RESULTS: The arithmetic mean of cadmium content in rice was 70.8 ± 44.7 µg/kg (AM ± SD). The geometric mean of daily cadmium intake (Cd intake) from rice calculated based on food consumption data was 9.12 µg/day (GSD 2.33). The geometric means of serum and urine cadmium concentrations were 1.57 µg/l (GSD 2.11) and 1.93 µg/g creatinine (cr.) (GSD 2.05), respectively. Multiple regression analysis showed positive correlations between (1) urinary free deoxypyridinoline (FDPD-U) and Cd intake (p < 0.05), (2) urinary cross-linked N-telopeptides of type I collagen (NTx-U) and Cd intake (p < 0.05), and (3) FDPD-U or NTx-U and cadmium concentration in urine (p < 0.01). No significant correlation between the parameters of ultrasonic bone evaluation and cadmium associated biomarkers was observed. CONCLUSIONS: The results of the present study suggest the possibility of bone metabolic disorder induced by environmental low-grade cadmium exposure. With respect to osteoporosis, a long-term follow-up survey is required to assess the tolerable intake of cadmium in environmental exposure.

Dietary isoflavone intake, polymorphisms in the CYP17, CYP19, 17beta-HSD1, and SHBG genes, and risk of breast cancer in case-control studies in Japanese, Japanese Brazilians, and non-Japanese Brazilians.

We tested the hypothesis that polymorphisms in cytochrome P450c17alpha (CYP17), aromatase (CYP19), 17beta-hydroxysteroid dehydrogenase type I (17beta-HSD1) and sex hormone-binding globulin (SHBG) genes may modify the association between isoflavone intake and breast cancer risk. We conducted hospital-based, case-control studies in Nagano, Japan and Sao Paulo, Brazil. A total of 846 pairs (388 Japanese, 79 Japanese Brazilians, and 379 non-Japanese Brazilians) completed validated food frequency questionnaires. Four single nucleotide polymorphisms (SNPs) in CYP17 (rs743572), CYP19 (rs10046), 17beta-HSD1 (rs605059), and SHBG (rs6259) genes were genotyped. We found no association between the 4 SNPs and breast cancer risk. In combination analyses of isoflavone intake and SNPs, an inverse association between intake and risk was limited to women with at least one A allele of the rs605059 polymorphism for all 3 populations, albeit without statistical significance. For the rs6259 polymorphism, the inverse association was limited to postmenopausal Japanese with the GG genotype (odds ratio [OR] for highest vs. lowest tertile = 0.50, 95% confidence interval [CI] = 0.29-0.87; P for trend < 0.01), and to non-Japanese Brazilians with at least one A allele (OR for consumers vs. nonconsumer = 0.21, 95% CI = 0.06-0.77). We found no remarkable difference for the rs743572 and rs10046 polymorphisms. Our findings suggest that polymorphisms in the 17beta-HSD1 and SHBG genes may modify the association between isoflavone intake and breast cancer risk.

Dietary intake of folate, vitamin B2, vitamin B6, vitamin B12, genetic polymorphism of related enzymes, and risk of breast cancer: a case-control study in Japan.

We investigated associations among intake of folate, vitamin B2, vitamin B6, vitamin B12, and polymorphisms of 5,10-methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) genes and breast cancer risk in a Japanese population. A hospital based, case-control study was conducted in Nagano Prefecture, Japan, in 388 pairs of patients with histologically confirmed invasive breast cancer and age- and area-matched controls selected from medical checkup examinees. Energy-adjusted intakes of folate and other B vitamins were derived from a validated food frequency questionnaire. Genotyping was completed for MTHFR (C677T and A1298T) and MTR (A2756G). Odds ratios and 95% confidence intervals were calculated by the conditional logistical regression model. Median dietary folate intake (microg/day) in the control group was 438.2 (interquartile range: 354.9-542.9). Neither dietary intake of folate, vitamin B2, vitamin B6, or vitamin B12 nor polymorphisms of MTHFR or MTR genes were significantly associated with breast cancer risk. Further, no significant interaction was found among nutrients, polymorphisms, and breast cancer risk. Associations of nutrients with breast cancer risk did not differ by hormone receptors status. We conclude that dietary intake of folate and related B vitamins and genotypes of MTHFR or MTR have no overall association with breast cancer risk in Japanese women.

Altered expression of the human base excision repair gene NTH1 in gastric cancer.

A base excision repair enzyme, NTH1, has activity that is capable of removing oxidized pyrimidines, such as thymine glycol (Tg), from DNA. To clarify whether the NTH1 gene is involved in gastric carcinogenesis, we first examined the NTH1 expression level in eight gastric cancer cell lines, and the results showed that NTH1 expression was downregulated in all of them, including cell line AGS. Next, a comparison of excisional repair activity against Tg by empty vector-transfected AGS clones and FLAG-NTH1-expressing AGS clones showed that a low NTH1 expression level led to low capacity to repair the damaged base in the gastric epithelial cells. Reduced messenger RNA expression of NTH1 was also detected in 36% (18/50) of primary gastric cancers. Moreover, immunohistochemical analysis revealed that NTH1 was predominantly localized in the cytoplasm in 24% (12/50) of the primary gastric cancers in contrast to the nuclear localization in non-cancerous tissue, suggesting impaired excisional repair ability for nuclear DNA. No associations between clinicopathological factors and NTH1 expression level or localization pattern were detected in the gastric cancers. Next, we found two novel genetic polymorphisms, i.e. c.-163C>G and c.-241_-221del, in the NTH1 promoter region, and a luciferase assay showed that both were associated with reduced promoter activity. However, there were no associations between the polymorphisms and risk of gastric cancer in a gastric cancer case-control study. These findings suggested that downregulation of NTH1 expression and abnormal localization of NTH1 may be involved in the pathogenesis of a subset of gastric cancers.

Association between dietary heterocyclic amine levels, genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 and risk of colorectal cancer: a hospital-based case-control study in Japan.

OBJECTIVE: Although associations between dietary HCA intake and colorectal cancer risk have been investigated, results have been suggestive but inconsistent. The aim of this hospital-based case-control study was to examine the impact of heterocyclic amine (HCA) intake on colorectal cancer risk. A further objective was to investigate the possible effect of genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 on colorectal cancer. MATERIAL AND METHODS: HCA exposure data were assessed using a self-administered food frequency questionnaire, and estimated HCA intake was verified by measuring the PhIP value in human hair. A total of 117 cases and 238 controls were included in these analyses. Odds ratios (ORs) were calculated using conditional logistic regression analysis to compare intake levels between the first and third tertiles. RESULTS: No statistically significant increase in the risk of colorectal cancer with respect to total HCA intake was shown by analysis (OR = 0.99, 95% CI = 0.21-4.81). Furthermore, no association with risk was seen for individual HCAs, including PhIP, MeIQ, and MeIQx. Although variant alleles of CYP1A2 were associated with colorectal cancer (OR = 0.27; 95% CI = 0.07-0.99), genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 did not influence the association of HCA intake with colorectal cancer. CONCLUSIONS: In the present study in subjects with low HCA exposure and with a limited sample size, no association was found between HCA intake and colorectal cancer, or any evidence of influence by genetic polymorphisms of NAT2, CYP1A1, and CYP1A2.

Isoflavone, polymorphisms in estrogen receptor genes and breast cancer risk in case-control studies in Japanese, Japanese Brazilians and non-Japanese Brazilians.

Epidemiologic studies have shown an inverse association between isoflavones and breast cancer risk. Because isoflavones bind estrogen receptors, we hypothesized that polymorphisms in the estrogen receptor genes might modify the association between isoflavone intake and breast cancer risk. We conducted hospital-based case-control studies of patients aged 20-74 years with primary, incident, histologically confirmed invasive breast cancer, and matched controls from among medical checkup examinees in Nagano, Japan, and from cancer-free patients in São Paulo, Brazil. A total of 846 pairs (388 Japanese, 79 Japanese Brazilians and 379 non-Japanese Brazilians) completed validated food frequency questionnaires, and provided blood samples. Five single nucleotide polymorphisms in the estrogen receptor alpha (rs9340799, rs1913474, and rs2234693) and beta (rs4986938 and rs1256049) genes were genotyped. We found no consistent association between the five single nucleotide polymorphisms and breast cancer risk among the three populations. In analyses of combinations of isoflavone intake and single nucleotide polymorphisms, an inverse association between intake and risk was limited to women with the GG genotype of the rs4986938 polymorphism for postmenopausal Japanese (odds ratio for highest versus lowest tertile = 0.47; P for trend = 0.01), Japanese Brazilians (odds ratio for highest versus lowest median = 0.31) and non-Japanese Brazilians (odds ratio for consumers versus non-consumers = 0.37) (P for interaction = 0.11, 0.08, and 0.21, respectively). We found no remarkable difference for the other four polymorphisms. Our findings suggest that polymorphisms in the estrogen receptor beta gene may modify the association between isoflavone intake and breast cancer risk.

Association between dietary heterocyclic amine levels, genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 and risk of stomach cancer: a hospital-based case-control study in Japan.

BACKGROUND: Although the associations between grilled (broiled) or barbecued meats or fish intake and stomach cancer risk have been investigated, the evidence implicating heterocyclic amine (HCA) intake as a cause of stomach cancer is limited. We conducted a case-control study to investigate the association between HCA intake and stomach cancer risk. We also investigated the possible effect of genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 on stomach cancer. METHODS: HCA exposure data were assessed using a self-administered food-frequency questionnaire, and estimated HCA intake was verified by measuring 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) values in human hair. A total of 149 cases and 296 controls were included in the analyses. Odds ratios (ORs) were calculated, using conditional logistic regression analysis, to compare intake levels between the first and third tertiles. RESULTS: Results showed no statistically significant increase in the risk of stomach cancer with respect to total HCA intake (OR, 1.11; 95% confidence interval [CI], 0.36, 3.49), or with respect to the intake of individual HCAs; namely, PhIP, 2-amino-3, 4-dimethylimidazo[4,5-f]quinoline (MeIQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). Genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 did not influence the association of HCA intake with stomach cancer. CONCLUSION: In the present study, with a limited sample size of subjects with low HCA exposure, no association was found between HCA intake and stomach cancer, nor was there any evidence of any influence by genetic polymorphisms of NAT2, CYP1A1, and CYP1A2 on the risk of stomach cancer.

Dietary isoflavone intake and breast cancer risk in case-control studies in Japanese, Japanese Brazilians, and non-Japanese Brazilians.

Although epidemiologic studies have shown an inverse association between isoflavones and breast cancer risk, little evidence for a dose-response relation is available. We conducted hospital-based case-control studies of patients aged 20-74 years with primary, incident, histologically confirmed invasive breast cancer, and matched controls from medical checkup examinees in Nagano, Japan and from cancer-free patients in São Paulo, Brazil. A total of 850 pairs (390 Japanese, 81 Japanese Brazilians and 379 non-Japanese Brazilians) completed validated food frequency questionnaires. The odds ratio of breast cancer according to isoflavone intake was estimated using a conditional logistic regression model. We found a statistically significant inverse association between isoflavone intake and the risk of breast cancer for Japanese Brazilians and non-Japanese Brazilians. For Japanese, a non-significant inverse association was limited to postmenopausal women. In the three populations combined, breast cancer risk linearly decreased from 'no' to 'moderate' isoflavone intake and thereafter leveled off. Compared to non-consumers, adjusted odds ratios (95% confidence interval) for consumers in increasing quintile intake categories (median intake in each category: 8.7, 23.1, 33.8, 45.7, and 71.3 mg/day) were 0.69 (0.44-1.09), 0.54 (0.31-0.94), 0.45 (0.26-0.77), 0.34 (0.19-0.62), and 0.43 (0.24-0.76), respectively. Overall, we found an inverse association between dietary isoflavone intake and risk of breast cancer. Our finding suggests a risk-reducing rather than risk-enhancing effect of isoflavones on breast cancer within the range achievable from dietary intake alone. In addition, women may benefit from risk reduction if they consume at least moderate amounts of isoflavones.

Validity of a self-administered food frequency questionnaire in the assessment of heterocyclic amine intake using 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) levels in hair.

Several case-control studies have reported possible associations between heterocyclic amine (HCA) intake and the risk of cancer. The validity of questionnaires used to assess HCA intake has hardly been examined, however; in particular, no biomarker able to serve as an independent measure of habitual HCA intake has been established. In this study, we examined the validity of HCA intake estimated from a food frequency questionnaire (FFQ) using 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) level in hair as a reference method. Study subjects were 20 volunteers (7 men and 13 women) aged 25-57 years residing in Tokyo or neighboring cities in Japan. The subjects completed the FFQ, and gave 3-5g of hair twice at an interval of 1-3 months for use in establishing validity. Results showed that intakes of PhIP, MeIQ, Trp-P-1, and total HCA by the FFQ were significantly correlated with PhIP levels in hair when adjustment was made for melanin content (r=0.47, r=0.50, r=0.55, and r=0.51, respectively). The present study indicates that HCA intake estimated from this FFQ provides a reasonable ranking of individuals to allow the analysis of associations between HCA intake and risk of cancer in large-scale epidemiological studies.

Impact of the revision of a nutrient database on the validity of a self-administered food frequency questionnaire (FFQ).

BACKGROUND: Revision of the national nutrient database in 2000 had a strong impact on the absolute level of estimated nutrient intake in dietary assessments. However, whether it influenced the ranking of individuals by estimated intake, a more important function in epidemiologic studies, has not been investigated. Here, we investigated the effect of this revision of the nutrient database on the validity of a food frequency questionnaire (FFQ) used to estimate nutrient intake in the Japan Public Health Center-based prospective Study (JPHC Study). METHODS: Subjects were a subsample of the JPHC Study who volunteered to participate in the validation study of the FFQ. Validity of the FFQ was evaluated by reference to the 28-day weighed dietary records as a gold standard. Nutrient intake according to the FFQ was recalculated using the revised database, and the results were compared to those using the previous database. Spearman's rank correlation coefficients (CCs) between intakes estimated by the FFQ and dietary records were computed using the revised database, and were compared to CCs computed using the previous database. RESULTS: For most of the nutrients, mean intake increased or decreased significantly using the revised database. However, no notable change was seen for the CC between estimated intake according to dietary records and FFQ when the revised database was used for calculation. Differences in the point estimates of the CCs ranged from -0.14 to 0.15. Likewise, CCs between biomarkers and estimated intake according to FFQ were similar for the two databases. CONCLUSION: Despite changes in intake levels for many nutrients, the validity of our FFQ using rank correlation by nutrient intake was not influenced by revision of the nutrient database in Japan.