Tetsuya Mizoue

Dietary factors and stomach cancer mortality

The present study examined the relationship between stomach cancer and the low intake of fresh fruit and vegetables and/or a high intake of pickled, preserved or salted foods and frequent use of cooking oil. During 139 390 person–year of follow-up of over 13 000 subjects, 116 died from stomach cancer. Using a Cox proportional hazards–regression analysis of relative risk (RR, 95% CI) controlling for age, sex, smoking and other dietary factors, a significant decline was found with a high consumption of green and yellow vegetables (RR=0.4, 95% CI=0.2–0.9). Reductions of between 40 and 50% were also observed with a high consumption of fresh foods (fruit, cuttle fish, tofu, and potatoes), but these associations were not statistically significant. The risk was significantly increased by the high consumption of processed meat (RR=2.7, 95% CI=1.0-7.4) and by the frequent use of cooking oil (RR=4.0, 95% CI=1.3-11.8). The high consumption of pickled food and traditional soups also increased risk, but not significantly. The findings suggest that a diet high in salt and low in vitamins may be associated with an increase in stomach cancer.

Calcium, vitamin D and dairy intake in relation to type 2 diabetes risk in a Japanese cohort.

Aims/hypothesisCalcium and vitamin D have been implicated in the development of type 2 diabetes, but epidemiological evidence is limited. We examined prospectively the relation of calcium and vitamin D intake to type 2 diabetes risk in a Japanese cohort.MethodsParticipants were 59,796 middle-aged and older men and women, who participated in the Japan Public Health Center-based Prospective Study and had no history of type 2 diabetes or other serious diseases. Dietary intake of calcium and vitamin D were estimated using a validated food frequency questionnaire. Logistic regression was used to assess the association between intake of these nutrients and self-reported newly diagnosed type 2 diabetes.ResultsDuring a 5xa0year follow-up, 1,114 cases of type 2 diabetes were documented. Overall, calcium intake was not associated with a significantly lower risk of type 2 diabetes; the multivariable odds ratio for the highest vs lowest quartiles was 0.93 (95% CI 0.71–1.22) in men and 0.76 (95% CI 0.56–1.03) in women. However, among participants with a higher vitamin D intake, calcium intake was inversely associated with diabetes risk; the odds ratio for the highest vs lowest intake categories was 0.62 (95% CI 0.41–0.94) in men and 0.59 (95% CI 0.38–0.91) in women. Dairy food intake was significantly associated with a lower risk of type 2 diabetes in women only.Conclusions/interpretationCalcium and vitamin D may not be independently associated with type 2 diabetes risk. Our finding suggesting a joint action of these nutrients against type 2 diabetes warrants further investigation.

Coffee consumption and glucose tolerance status in middle-aged Japanese men.

Aims/hypothesisSeveral studies have reported that coffee has a protective effect against the development of type 2 diabetes. However, few of these studies used the standard glucose tolerance test to diagnose type 2 diabetes. The aim of this study was to investigate the relationship between coffee and green tea consumption and glucose tolerance status as determined using a 75-g OGTT.MethodsWe performed a cross-sectional study of 3224 male officials of the self-defence forces. Glucose tolerance status was determined in accordance with the 1998 World Health Organization criteria, and average intakes of coffee and green tea over the previous year were assessed by a self-administered questionnaire. The figures obtained were adjusted for BMI, physical activity and other factors.ResultsA total of 1130 men were identified as having glucose intolerance (IFG, IGT or type 2 diabetes). Compared with those who did not consume coffee on a daily basis, fasting and 2-h post-load plasma glucose levels were 1.5% and 4.3% lower in those who drank 5 cups of coffee or more per day respectively. The adjusted odds ratios of glucose intolerance for categories of <1, 1–2, 3–4 and ≥5 cups of coffee per day were 1.0 (referent), 0.8 (95% CI 0.6–1.0), 0.7 (95% CI 0.6–0.9) and 0.7 (95% CI 0.5–0.9) respectively (p=0.0001 for trend). No clear association was observed between green tea drinking and glucose tolerance status.Conclusions/interpretationCoffee consumption may inhibit postprandial hyperglycaemia and thereby protect against the development of type 2 diabetes mellitus.

Prospective study of screening for stomach cancer in Japan

Although screening for stomach cancer is a widespread community service in Japan, the benefits of the screening program remain unclear. Our study investigated prospectively the relation between participation in stomach‐cancer screening during the past 12 months and subsequent deaths. Data was derived from the Japan Collaborative Cohort Study, in which 480 stomach‐cancer deaths were identified during an 8‐year follow‐up period. Cox proportional hazard regression was used to estimate the relative risk of death from stomach cancer and that from other causes while adjusting for potential confounding factors. In men, screening participation was associated significantly with a reduced risk of death from stomach cancer (relative risk [RR] = 0.54; 95% confidence interval [CI] = 0.41–0.70). The extent of the risk reduction was greater than potential health selection (for deaths other than stomach, RR = 0.71). The adjustment for potential confounding variables, however, attenuated the difference in risk of death (stomach cancer, RR = 0.65; other causes, RR = 0.71). In women, the magnitude of the association between screening participation and death from stomach cancer (RR = 0.74; 95% CI = 0.52–1.07) was equal to that for deaths from non‐stomach cancers (RR = 0.74). Subgroup analysis showed that women with a parental history of stomach cancer had a reduced risk of death from stomach cancer associated with screening (RR = 0.32; 95% CI = 0.12–0.87). The present results underline the potential for selection bias in observational studies, and thus it remains an open question whether screening for stomach cancer is effective.

Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and colorectal cancer: the Fukuoka Colorectal Cancer Study.

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating folate metabolism, which affects DNA synthesis and methylation. This study investigated the relation of MTHFR C677T and A1298C polymorphisms to colorectal cancer in a case‐control study in Fukuoka, Japan. The subjects comprised 685 incident cases of histologically confirmed colorectal adenocarcinomas and 778 community controls selected randomly in the study area. The genotype was determined by the PCR‐RFLP method using genomic DNA extracted from buffy coat. Alcohol use was ascertained by in‐person interview. Statistical adjustment was made for gender, age class, area, and alcohol use. The MTHFR 677TT genotype was associated with a statistically significant decrease in the risk with an adjusted odds ratio of 0.69 (95% confidence interval 0.51–0.93) compared with the 677CC and 677CT combined, and the decrease was most evident in individuals with no alcohol consumption. While the A1298C polymorphism showed no measurable association with the overall risk of colorectal cancer, the 1298CC genotype was associated with a statistically significant increase in the risk when alcohol consumption was high, and was also associated with an approximately 2‐fold increase in the risk of each of proximal and distal colon cancer. The findings add to evidence that individuals with the MTHFR 677TT genotype have a decreased risk of colorectal cancer in the absence of folate depletion, suggesting a protective role of folate by ensuring a sufficient thymidylate pool for DNA synthesis. Because very few individuals had the 1298CC genotype, the findings regarding the A1298C polymorphism need careful interpretation and confirmation in larger studies.

A prospective study of stomach cancer death in relation to green tea consumption in Japan

To evaluate whether green tea consumption provides protection against stomach cancer death, relative risks were calculated using Cox proportional hazards regression analysis in the Japan Collaborative Study for Evaluation of Cancer Risk, sponsored by the Ministry of Health and Welfare (JACC Study). The study was based on 30 370 men and 42 481 women aged 40–79. After adjustment for age, smoking status, history of peptic ulcer, family history of stomach cancer along with certain dietary items, the risks associated with drinking one or two, three or four, five to nine, and 10 or more cups of green tea per day, relative to those of drinking less than one cup per day, were 1.6 (95% CI: 0.9–2.9), 1.1 (95% CI: 0.6–1.9), 1.0 (95% CI: 0.5–2.0), and 1.0 (95% CI: 0.5–2.0), respectively, in men (P for trend=0.669), and 1.1 (95% CI: 0.5–2.5), 1.0 (95% CI: 0.5–2.5), 0.8 (95% CI: 0.4–1.6), and 0.8 (95% CI: 0.3–2.1), respectively, in women (P for trend=0.488). We found no inverse association between green tea consumption and the risk of stomach cancer death.

Health-related quality of life of mothers of children with leukemia in Japan.

Objective: The study compared the health-related quality of life (HRQOL) of Japanese mothers of children with leukemia to that of mothers of children without leukemia. Method: We used the Medical Outcomes Study 36-item Short-Form (SF-36) to measure the HRQOL of 97 mothers of children (average age 6.2, range 0–14) with leukemia diagnosed between 1999 and 2000, and compared their scores to those of 240 mothers of children without leukemia matched to the children with leukemia. Main results: Of the eight unadjusted domain scores of the SF-36, five were significantly low among mothers of children with leukemia compared to mothers of children without leukemia: ‘role-physical functioning’ (RP), ‘general health perception’ (GH), ‘vitality’ (VT), ‘social functioning’ (SF) and ‘mental health’ (MH). Their SF-36 domain scores, when adjusted for demographic and clinical factors were also significantly low in RP, GH, VT, SF, RE and MH. The MH and SF scores in mothers of children with leukemia requiring hospital care were, respectively, approximately 20 points (1 standard deviation (SD), p < 0.0001) and 30 points (1.5 SD, p < 0.0001) lower than that of mothers of children without leukemia. Conclusion: Mothers of children with leukemia requiring hospital care have poor HRQOL, particularly with regard to mental health and social functioning, and are at a greater risk for depression. These results suggest that the current system for treating leukemic diseases of children in Japan should also include close monitoring of mothers’ mental health, and provision of appropriate treatment and psycho-social support.

A nested case–control study of stomach cancer in relation to green tea consumption in Japan

To evaluate whether green tea consumption provides protection against stomach cancer, the relative risks (RRs) were calculated in the Japan Collaborative Study for Evaluation of Cancer Risk, sponsored by the Ministry of Health and Welfare (JACC Study). The study was based on 157 incident cases and 285 controls aged 40–79 years. Cox proportional hazards regression analysis was used to estimate the RRs for stomach cancer. It was found that green tea consumption had no protective effect against stomach cancer. After adjustment for age, smoking status, H. pylori infection, history of peptic ulcer, and family history of stomach cancer along with certain dietary elements, the risks associated with drinking one or two, three or four, five to nine, and 10 or more cups of green tea per day, relative to those of drinking less than one cup per day, were 1.3 (95% confidence interval (CI): 0.6–2.8), 1.0 (95% CI: 0.5–1.9), 0.8 (95% CI: 0.4–1.6), and 1.2 (95% CI: 0.6–2.5), respectively (P for trend=0.899). We found no inverse association between green tea consumption and the risk of stomach cancer.

Menstrual and reproductive factors and the mortality risk of gastric cancer in Japanese menopausal females

Objective: The relationship between gastric cancer and menstrual and reproductive history was investigated for 40,535 postmenopausal females from a large-scale prospective cohort in Japan (JACC: Japan Collaborative Cohort Study for Evaluation of Cancer Risk, sponsored by Monbusho). Methods: A Cox proportional hazard model was used to estimate risk with respect to menstrual and reproductive factors for gastric cancer mortality. The effects on risk of potential confounders such as lifestyle, dietary habits, and socioeconomic status were controlled for using a stepwise procedure. Results: During the study period (mean 8.2 years), 156 deaths due to gastric cancer were identified. Longer fertility tended to be inversely associated with risk of gastric cancer mortality, although the association was not significant. Late menopause had no obvious effect on gastric cancer risk. The risk ratio of delivery experience compared to no delivery was 0.62 (95% confidence interval 0.27–1.41), and this effect was consistent regardless of the number of deliveries. Early menarche was not associated with the risk of gastric cancer. The potential confounders were not seen to have distinct effects on the associations. Conclusions: Multiparity appears to confer a protective tendency on gastric cancer mortality; however, this result is inconsistent with previous reports. Further information needs to be accumulated from epidemiological studies in order to clarify the role of reproductive factors in gastric cancer.

Weight change and all-cause, cancer and cardiovascular disease mortality in Japanese men and women: the Japan Public Health Center-Based Prospective Study.

Background:It is unclear whether weight change during adulthood influences subsequent mortality in Asian populations, who have a relatively lean body mass.Objective:To assess the relation of weight change over 5 years to all-cause, cancer and cardiovascular disease mortality among Japanese men and women.Design:Subjects were 36u2009220 men and 44u2009091 women aged between 45 and 75 years without a history of serious disease at baseline. Weight change was calculated as the difference of body weight between two surveys with a 5-year interval.Results:During 699u2009963 person-years of follow-up, we identified 4232 deaths of all-cause, 1872 cancer deaths and 1021 cardiovascular deaths. The relation between weight change and all-cause mortality was reverse J-shaped. Multivariate hazard ratios (95% confidence interval) for weight loss of 5u2009kg or more versus weight change of less than 2.5u2009kg were 1.62 (1.45–1.81) in men and 1.76 (1.51–2.05) in women, whereas those for weight gain of 5u2009kg or more were 1.40 (1.22–1.59) in men and 1.25 (1.02–1.54) in women. These associations remained statistically significant even after the exclusion of deaths in the first 3 years of follow-up. The weight change–mortality association was pronounced in underweight persons or in nonsmoking men. The risk of cancer mortality increased in both men and women who lost weight by 5u2009kg or more. With regard to cardiovascular disease, mortality risk tended to increase with weight loss both in men and women, whereas its increase with weight gain was observed only in women.Conclusions:A large weight change, both loss and gain, was associated with an increased risk of mortality. Weight loss and gain may be predictors of early death in apparently healthy adult Japanese.