Sex and seasonal variations of plasma retinol, alpha-tocopherol, and carotenoid concentrations in Japanese dietitians.

AIM: To clarify sex and seasonal variations of plasma antioxidant concentrations among middle-aged Japanese. SUBJECTS AND METHODS: We investigated sex and seasonal variations of plasma antioxidant concentrations, including retinol, alpha-tocopherol, and carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and lycopene), in 55 middle-aged dietitians (46 women and 9 men) in Aichi Prefecture, Central Japan, who took no supplements from autumn 1996 to summer 1997. Reversed-phase high performance liquid chromatography was used to measure plasma antioxidant concentrations in overnight-fasting blood samples. RESULTS: Plasma levels of alpha-tocopherol, alpha-/beta-carotene, b-cryptoxanthin and lutein were significantly influenced by sex, being significantly higher for women than men in each corresponding season; retinol and lycopene, however, showed no such difference. For women, winter values of alpha-tocopherol, alpha-/beta-carotene, lutein and lycopene were significantly lower than corresponding summer values, and had reached their annual lowest. Retinol failed to show any significant seasonal variation, whereas the winter value of beta-cryptoxanthin had reached its annual highest. For men, beta-cryptoxanthin exhibited significant seasonal changes and was also highest in winter. Winter values of alpha-tocopherol, alpha-/beta-carotene and lycopene were lower compared with other seasons, but not statistically significant, probably due to the small sample size. CONCLUSIONS: The findings indicate that sex and seasonal variations of plasma antioxidant concentrations should be taken into account in nutritional epidemiologic studies.

Gastric and colo-rectal cancer mortality in Viet Nam in the years 2005-2006.

BACKGROUND: The International Collaborative Epidemiological Study of Host and Environmental Factors for Stomach and Colorectal Cancers in Southeast Asian Countries (SEACs) has been conducted in Viet Nam from 2003 to 2008 on a case-control basis. For further effective primary prevention, we examined gastric and colorectal cancer mortality nationwide in eight regions of Viet Nam in 2005-06. METHODS: Both demographic data and lists of all deaths in 2005-06 were obtained from all 10,769 commune health stations in Viet Nam. Five indicators included name, age, sex, date of death and cause of death was collected for each case. We selected only communes having the list of deaths with clear cause for each case and crude mortality rate for all causes from 300-600/100,000 as published by the Ministry of Health for a reasonable accuracy and completeness. Obtained data for all causes, all cancers, stomach and colorectal cancer deaths as well as demographic information were processed using Excel software and exported to STATA 8.0 for estimation of world age-standardized cancer mortality rates per 100,000. RESULTS: Data were available for 1,246 gastric cases, (819 male and 427 female) with age-standardized mortality rates from 12.7 to 31.3 per 100,000 in males and from 5.9 to 10.3 per 100,000 in females in the 8 regions of the country. For colorectal cancers, 542 cases (268 male and 274 female) gave mortality rates from 4.0 to 11.3 per 100,000 in males and from 3.0 to 7.8 per 100,000 in females. DISCUSSION: Stomach cancer mortality in males in the region of North East in the North Viet Nam (2005-06) was higher than that in Japan (2002) (31.3 versus 28.7 per 100,000) while colorectal cancer in Viet Nam was lower. While prevalence of Helicobacter pyloris infection in Viet Nam was from 70-75% in both males and females, the stomach cancer rate in males was significantly higher than in females, 31.3 versus 6.8 per 100,000, suggesting an influence of other environmental risk factors. Whether protective factors are operating against colorectal cancer in Viet Nam now needs to be explored.

Lifestyle-related risk factors for stomach cancer in northeast Thailand.

BACKGROUND: Stomach cancer is not common in Thailand but the life styles of the Thai population are changing to become more Western so that information for planning control programme of stomach cancer is necessary. The highest incidence rates of this neoplasm are found in Eastern Asia, ranging from age-standardized rates of 95.5/105 (men) and 40.1/105 (women) in Yamagata, Japan to 4.1/105 (men) and 2.1/105 (women) in Khon Kaen, Northeast of Thailand. In Thailand, the estimated age-standardized incidence rates in 1993, 1996 were 4.9/105, 4.1/105 in men and 3.0/105 , 2.6/105 in women. Risk factors for stomach cancer in Thai population are unclear, but possibly include low intake of vegetables and fruits, alcohol drinking, tobacco smoking and high intake of salt. OBJECTIVE: To investigate various aspects of dietary factors, smoking, and alcohol drinking in determining risk of stomach cancer in Thai population. METHODS: A case-control study was conducted in Khon Kaen, Thailand during 2002-2006, to study the role of these factors in stomach cancer. 101 stomach cancer cases and 202 matched controls (case : control = 1:2) by sex, age (? 3 years) and region were recruited from Srinagarind Hospital and Khon Kaen Regional Hospital, in Khon Kaen Province. All of cases were histologically confirmed. Controls had a variety of diseases, the main ones being disease of the eye. Information on dietary habits, alcohol drinking and smoking were collected by a structured questionnaire, blood samples were collected for further study. RESULTS: The distribution of the general characteristics by case-control status, the distribution of age and sex were similar in cases and controls. In the final analysis, the factors that found to be higher risk but not statistically significant were long-term filter cigarette smoking (OR=1.9, 95%CI: 0.85-4.50), long-term alcohol consumption (OR=1.2, 95%CI: 0.51-2.60) and low intake of vegetables and fruits (OR=1.2, 95%CI: 0.74-1.96). A high intake of vegetable oil (OR=4.5, 95%CI: 1.00.-20.17) was found to be associated with increased risk, and similar tendencies were noted for pork oil (OR=1.4, 95%CI: 0.63-3.01) and jeaw prik (mainly chilly with plara broth) (OR=1.2, 95%CI: 0 .76- 2.01). CONCLUSION: Our study confirmed protective effects of a high intake of fruits and vegetables against stomach cancer development and showed a high intake of sauces to increase risk of stomach cancer as in other countries in Asia.

Serum concentrations of fatty acids and colorectal adenoma risk: a case-control study in Japan.

BACKGROUND: Epidemiologic studies of n-3 fatty acids (FAs) and risk of colorectal cancer have generated inconsistent results, and relations with precursor colorectal adenomas (CRA) have not been evaluated in detail. We here focused on possible associations of serum FAs with CRA in the Japanese population. METHODS: We conducted a case-control study of 203 asymptomatic CRA cases (148 men, 55 women) and 179 healthy controls (67 men, 112 women) during 1997-2003 in Nagoya, Japan. Baseline information was obtained using a lifestyle questionnaire and serum FA levels were measured by gas chromatography. RESULTS: A non-significant inverse association with CRA was observed for eicosapentaenoic acid (EPA) among women. Moreover, the concentrations of docosahexaenoeic acid (DHA), a major component of n-3 highly-unsaturated FAs (HUFAs), were significantly lower in cases in both sexes. In addition, serum concentrations of total FAs, saturated FAs (SFAs) and mono-unsaturated FAs (MUFAs) had strong positive links with CRA risk. In contrast, arachidonic acid (AA) and DHA were inversely related, with 66% and 59% risk reduction, respectively. Ratios of SFAs/n-3 PUFAs and SFAs/n-3 HUFAs exhibited significant positive relations with CRA risk but there was no clear link with n-6 PUFAs/n-3 PUFAs. CONCLUSIONS: Our findings suggest a promoting influence of SFAs and MUFAs along with a protective effect of DHA on CRA risk. However, further research is needed to investigate the observed discrepancy with the generally accepted roles of the AA cascade in carcinogenesis.

Risk factors for colorectal cancer in northeast Thailand: lifestyle related.

BACKGROUND: The incidence of colorectal cancer is variable around the world. Hiroshima, Japan had the highest incidence in men in 1997 with an age-standardized rate of 86.7 per 100,000 and New Zealand had the highest, at 40.6 per 100,000, in women. The incidence of colorectal cancer in Thailand is rather low and the latest figures for Northeast of Thailand are 7.1 per 100,000 for men and 4.7 for women. The reasons for these differences between countries are possibly due to variation in dietary habits, alcohol drinking or other cofactors. METHODS: A case-control study was conducted in Khon Kaen, Northeast Thailand during 2002-2006 to study risk factors for colorectal cancer in a low risk area. Totals of 253 colorectal cancer cases (males 135, females 118) and 253 age- and sex-matched controls were recruited. Information on dietary habits, alcohol drinking, smoking and other information were collected by a structured questionnaire. Blood samples were collected for further study. Both univariate and multivariate analyses were carried out. RESULTS: In the final model of multivariate analysis, the significant risk factors for colorectal cancer were a family history of cancer (OR=1.9 95%CI=1.2-2.9) and meat consumption (OR=1.0 95%CI=1.0007-1.0026). For BMI, subjects with higher BMI unexpectedly had a lower risk of colorectal cancer (OR=0.5 95%CI=0.3-0.8). CONCLUSION: Our study confirmed risk factors for colorectal cancer i.e. meat consumption and cancer in the family (genetic problem). However, the results for BMI are the reverse of expected, underlining one limitation of hospital-based case-control studies, in which cases are ill and admitted to the hospital at late stage.

Are there any real Helicobacter pylori infection-negative gastric cancers in Asia?

The great variability in gastric cancer rates across Asia, with very high incidences in Japan and Korea, and exceedingly low incidences in ethnic Malays, whether in Malaysia or Indonesia, appears largely due to variation in Helicobacter pylori infection rates. While between 2% and 10.6% of gastric cancers in a recent Japanese survey were considered to be negative for bacterial infection on the basis of seropositivity and H. pylori-dependent mucosal atrophy, it is notoriously difficult to preclude past infection. The situation is greatly complicated by reported differences in the etiology of gastric cardia and non-cardia cancers. In the Western world there do appear to be tumours arising close to the esophageal-gastric junction which are not related to H. pylori and associated inflammation, but in most Asian populations these appear to be very rare. Therefore preventive efforts, and particularly screening, should be focused on markers of bacterial infection, with avoidance of unnecessary exposure to X-ray radiation.

Risk of endometrial cancer mortality by ever-use of sex hormones and other factors in Japan.

OBJECTIVES: To examine associations of ever-use of sex hormones (EUSH) and other factors with endometrial cancer (EC) mortality through a nation-wide Japan Collaborative Cohort Study. METHODS: A total of 63,541 women aged 40-79 years, enrolled in 1988-90 from 45 municipalities of Japan, were followed until 2003 to record their vital status. Using baseline data, the Cox proportional hazard model (age adjusted and multivariate) was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for EC mortality by selected factors, including EUSH. Bivariate analysis was also conducted to establish associations between EUSH and other factors. RESULTS: The mortality rate from EC was 2.6 per 100,000 person-years during the mean follow-up period of 13.3 years. Prevalence rate of EUSH was 5.2%. Significantly increased risk of EC mortality was found for EUSH with both age adjusted (HR=6.43, 95%CI=2.10-19.67) and multivariate (HR=5.33; 95%CI=1.51-18.82) analyses. Bivariate analysis indicated that history of diabetes mellitus, smoking, drinking, and age at first delivery were positively associated with EUSH, whereas age, number of delivery, number of pregnancy, and age at menarche demonstrated inverse links. CONCLUSIONS: Our results imply that EUSH may increase the risk of EC mortality among Japanese women. However, further studies with more deaths are needed to validate the results.

Comparison of Japanese, American-Whites and African-Americans--pointers to risk factors to underlying distribution of tumours in the colorectum.

Relative incidence rates for colon and rectal cancer vary greatly between populations in the world. While Japanese have historically had low prevalence, immigration to the United States has now resulted in equal if not higher rates than in Caucasian- or African-Americans. Furthermore, recent data from some population-based registries in Japan itself are also pointing to particularly high susceptibility. Of particular interest is the fact that Japanese in both the home country and the US in fact have far higher rates for rectal cancer than the other two ethnic groups. An intriguing question is whether they might also demonstrate variation from Caucasian- and African-Americans in the relative incidence rates for proximal and distal colon cancers, given the clear differences in risk factors like diabetes, physical exercise, smoking, alcohol consumption, meat and fish intake and calcium exposure which have been shown to operate in these two sites. A comprehensive epidemiological research exercise is here proposed to elucidate ethnic variation in colorectal cancer development, based on cross-cancer registry descriptive and case control approaches. It is envisaged that additional emphasis on screened populations should further provide important insights into causal factors and how primary and secondary prevention efforts can be optimized.

Relation of the CD36 gene A52C polymorphism to the risk of colorectal cancer among Japanese, with reference to with the aldehyde dehydrogenase 2 gene Glu487Lys polymorphism and drinking habit.

High consumption of white meat (or saturated fatty acids) and alcohol has been demonstrated to have a tendency to increase the risk of colorectal cancer, according to the level of malondialdehyde-deoxyguanosine adducts derived from lipid per-oxidation in the colorectal mucosa. CD36 plays important roles as a long-chain fatty acid translocase and oxidized low-density lipoprotein (LDL) scavenger, while alcohol is metabolized by aldehyde dehydrogenase 2 (ALDH2) and decreases transiently metabolism of dietary fat and serum lipids. To examine associations between the risk of colorectal cancer and the CD36 gene A52C polymorphism according to the ALDH2 gene Glu487Lys polymorphism and drinking habit, a hospital-based case-control study was conducted with 128 colorectal cancer cases and 238 cancer-free controls. Odds ratios (ORs) for the C/C genotype relative to the A/A genotype were 1.70 [95% confidence interval (CI), 0.76-4.11] and 4.24 (95% CI, 1.42-22.66) for men and women, respectively, with the low-activity (Glu/Lys + Lys/Lys) ALDH2 genotype. The high-activity (Glu/Glu) genotype for men and women had no associations. On the other hand, the OR for the C/C genotype with high frequency of drinking habit relative to the A/A genotype with low frequency of drinking habit among men was 3.63 (95% CI, 1.29-13.15). The number of women with a high frequency drinking habit was too small for any corresponding analyses. Our findings suggest a significant interaction between alcohol consumption and the CD36 gene A52C polymorphism related to the metabolism of long-chain fatty acids and oxidized LDL in the etiology of colorectal cancer.

Association between type II diabetes and colon cancer among Japanese with reference to changes in food intake.

Many epidemiological studies have provided support for the hypothesis that type II diabetes can increase the risk of colorectal cancer, but time trends, geographical distributions and host factors for the two diseases remain largely to be clarified. To address these issues, we investigated the epidemic pattern of colon cancer and type II diabetes among Japanese in Japan (J-Japanese), with consideration of the westernization of dietary habits. Over the last three decades, the increase in crude mortality rates of colon cancer from the Vital Statistics has closely paralleled the increment in prevalence rates (PRs) from hospital based surveys of diabetes. Age-standardized incidence rates (ASIRs) for colon cancer among Japanese in the United States (US-Japanese) were higher than those among J-Japanese and almost the same as those among US-Whites, while PRs for type II diabetes among US-Japanese were the highest in the three populations. Correlation analysis showed that PRs for type II diabetes had a positive association with ASIRs for colon cancer among the combination of Japanese and US-Japanese (r=0.79, p<0.01). Since 1950, intake of milk, meat, eggs and fat/oil has increased, while that of rice and potatoes has gradually decreased. Our findings indicate that the increment of ASIRs for colon cancer among J-Japanese might be closely associated with the increment of PRs for type II diabetes, reflecting the westernization of food intake.

Development of a data-based short food frequency questionnaire for assessing nutrient intake by middle-aged Japanese.

OBJECTIVE: Development of a data-based short food frequency questionnaire (FFQ) for evaluating intake of nutrients by middle-aged Japanese. METHODS: Of 102 foods listed in the formerly developed semi-quantitative FFQ, foods having similar nutrient contents were combined into 72 foods/food groups by research dietitians. Nutrient contents were computed by multiplying the weight of foods consumed and its nutrient contents. Next, a cumulative multiple regression coefficient up to 0.85 was applied, and 47 foods/food groups were chosen for a brief FFQ for assessing intake of 21 nutrients including energy, protein, fat, carbohydrate, vitamins, minerals, and dietary fibers. RESULTS: The 47 foods/food groups comprised rice, bread and noodles (3), margarine/butter (2), eggs (1), milk and dairy products (2), soybean and soybean products (3), miso-soup (1), meat including beef, pork and chicken (4), fish (3), other fish, shellfish and fish products (4), green-yellow vegetables (5), other vegetables and mushrooms (3), edible roots (4), seaweeds (1), mayonnaise (1), fried dishes (2), seeds (1), fruit (2), beverages, including alcohol (3), and confectioneries (2). CONCLUSIONS: The evidence-based short FFQ efficiently covered the intake of 21 nutrients, and may be competent to rank the middle-aged general public Japanese according to intake of nutrients.

Relationship between obesity and serum markers of oxidative stress and inflammation in Japanese.

The present study was conducted to assess the relationship between obesity and serum levels of C-reactive protein (CRP), carotenoids, oxidized LDL (oxLDL), oxidized LDL antibodies (oLAB), and leptin in Japanese residents. The subjects were 158 males and 158 females aged 40-79 years, and living in Hokkaido, Japan, who attended a health examination screening. Serum levels of CRP, oxLDL, oLAB, and leptin were measured by enzyme-linked immunosorbent assay (ELISA) and serum carotenoid levels were measured by high-performance liquid chromatography (HPLC). Body mass index (BMI) was calculated as body weight (kg) divided by height (m) squared and obesity was defined as BMI of 25 or more (kg/m2). Serum levels of CRP and leptin were significantly higher in the obese group than in their non-obese counterparts in both genders. Serum levels of beta-carotene and beta-cryptoxanthin were lower in the obese individuals, especially in females. While values for oxLDL and oLAB did not significantly vary. BMI was positively correlated with log-transformed serum levels of CRP and leptin in both genders (males: r=0.231, p<0.05; females: r=0.305, p<0.001). In females, moreover, BMI was negatively correlated with log-transformed serum levels of beta-carotene, zeaxanthin/lutein, and beta-cryptoxanthin (r=-0.244, p<0.01; r=-0.200, p<0.05; r=-0.207, p<0.01, respectively). Significantly higher odds ratios (ORs) for high serum levels of CRP (males: OR=2.12; females: OR=3.96) and leptin (males: OR=3.83; females: OR=9.07) were observed in obese versus non-obese men and women, after adjusting for various confounding factors. Significantly lower adjusted odds ratios for high serum levels of alpha- and beta-carotenes (males: OR=0.23, 0.33; females: OR=0.35, 0.39, respectively) were also observed in the obese as compared to the non-obese group. In conclusion, obesity is highly associated with states of oxidative stress and low-grade inflammation in Japanese residents, suggesting that these latter might play an important role in the association between a high BMI and certain cancers as well as coronary heart disease (CHD).

Grand challenges in global health and the practical prevention program? Asian focus on cancer prevention in females of the developing world.

In response to the request for 'Breakthrough Questions' for 'Grand Challenges in Global Health' recently published in Nature, the Asian Pacific Organization for Cancer Prevention should focus its attention on what projects are of the highest priority for integration with its Practical Prevention Program (PPP). The most common female cancers in most of the countries of Asia are carcinoma of the breast, followed by the uterine cervix. While the incidences of breast adenocarcinomas are still generally lower than in the Western world they are rapidly increasing, and squamous cell carcinomas of the cervix are a major problem. Clearly there are many areas which would reward research. One factor which appears of major relevance in the mammary gland case is the diet, and particularly the phytoestrogens included in 'tofu', along with physical exercise. The age at which these could be operating needs to be elucidated, with reference to timing of menarche and menopause, and also breast mammographic density, another predictor of likelihood of neoplasia. In the cervix, the predominant influence is well established to be persistent infection with a high risk 'oncogenic' type of human papilloma virus (HPV). Vaccines therefore hold much promise, but a better understanding of the mechanisms underlying spontaneous clearance of both infection and cervical intraepithelial neoplasia (CIN) of different grades is also essential for optimal intervention. The roles of smoking and antioxidant intake in particular deserve emphasis. In Asia, with the considerable variation evident in both breast and cervical cancer incidence rates, as well as in cultural and other environmental factors, we are in a very favourable position to meet two specific challenges: 1). elucidation of how diet in adolescence determines susceptibility to neoplasia of the mammary glands; and 2). determination of what governs persistence of HPV infection. Realisation of these pivotal research aims, with especial emphasis on the context of the PPP, is our shared goal.