National Nutrition Survey in Japan

Trends in Mean Energy and Nutrient Intakes in Japanese Children and Adolescents: The National Health and Nutrition Survey, 1995-2019

This study aimed to describe the national trends in mean energy and nutrient intakes in Japanese children and adolescents from 1995 to 2019. We used data obtained from the National Health and Nutrition Survey and included 54,871 participants aged 1-19 years. The dietary intake was estimated using a 1-day, semi-weighed, household-based, dietary record. The trends of mean energy and nutrient intakes were analyzed using the Joinpoint Regression Program. A declining trend in the mean energy intake was observed in toddlers aged 1-6 years, school girls aged 7-14 years, and adolescent girls aged 15-19 years, while the mean energy intake from protein, fat, and carbohydrates changed little over time. The mean salt equivalent showed a decreasing trend in all age groups, although the 2019 mean values were above the tentative dietary goal for preventing lifestyle-related diseases, especially in adolescent boys. Declining trends in mean vitamin (vitamin A, vitamin B12, folate, vitamin D, and vitamin K) and mineral (calcium, iron, and copper) intakes were observed, while trends in the mean vitamin B6 and zinc intakes were unchanged since 2001. Continuous monitoring of dietary intake and further research are required to raise awareness of unhealthy diet habits and to improve the food environment for the healthy growth and development of children and adolescents.

Dietary Factors, Dietary Patterns, and Cardiovascular Disease Risk in Representative Japanese Cohorts: NIPPON DATA80/90

Diet is one of the most important factors affecting healthy life expectancy through the onset of cardiovascular disease (CVD) risk as well as various chronic diseases. Because dietary habits and disease structure differ depending on the country, region, and/or race, evidence from each population is required. NIPPON DATA80/90 is a long-term cohort study of a representative Japanese population that participated in national nutrition surveys. Among the many findings of this cohort study, a dietary pattern with higher intake of fruits, vegetables, fish (n-3 polyunsaturated fatty acids), and dietary fiber and lower intake of salt as well as sodium-to-potassium ratio was found to be associated with a lower risk of CVD mortality. The results from our cohort study would be useful for effectively preventing CVD. This article reviews the published studies from the NIPPON DATA80/90 to highlight the significant findings that may be used to develop risk prevention strategies for CVD.

Predictors of lower limb fractures in general Japanese: NIPPON DATA90

Objective

This study aimed to investigate the incidence rates and predictors of lower limb fractures in a general Japanese population.

Methods

NIPPON DATA is a nationwide, long-term, prospective cohort study of individuals who participated in the National Cardiovascular Survey Japan and the National Nutrition Survey in 1990. Overall, 3,134 individuals (1,827 women, 1,307 men) who participated in follow-up assessments in 1995, 2000, and/or 2006 were included in the present analysis. The outcomes of this study were lower limb fractures (including proximal femur fractures).

Results

The mean age at baseline was 63.8 years in women and 63.1 years in men. The average body mass index (BMI) was 23.3 kg/m² in women and 22.9 kg/m² in men. During a mean follow-up of 12.1 years, 271 total lower limb fractures were observed. In women, older age, lower BMI, and less intake of vegetables were associated with increased risks of proximal femur fractures. With regard to the outcome of total lower limb fractures, less intake of vegetables and regular exercise were significant predictors in women. Calcium intake was not significantly associated with proximal femur or total lower limb fractures. There were no significant predictors of proximal femur or total lower limb fractures in men, except for age.

Conclusions

Aging was a significant risk factor for proximal femur and total lower limb fractures in both men and women. With regard to modifiable risk factors, low BMI and low intake of vegetables were associated with increased risks of proximal femur and/or total lower limb fractures in the general population of Japanese women.

Comparison of All Solid Cancer Mortality and Incidence Dose-Response in the Life Span Study of Atomic Bomb Survivors, 1958-2009

Recent analysis of all solid cancer incidence (1958-2009) in the Life Span Study (LSS) revealed evidence of upward curvature in the radiation dose response among males but not females. Upward curvature in sex-averaged excess relative risk (ERR) for all solid cancer mortality (1950-2003) was also observed in the 0-2 Gy dose range. As reasons for non-linearity in the LSS are not completely understood, we conducted dose-response analyses for all solid cancer mortality and incidence applying similar methods [1958-2009 follow-up, DS02R1 doses, including subjects not-in-city (NIC) at the time of the bombing] and statistical models. Incident cancers were ascertained from Hiroshima and Nagasaki cancer registries, while cause of death was ascertained from death certificates throughout Japan. The study included 105,444 LSS subjects who were alive and not known to have cancer before January 1, 1958 (80,205 with dose estimates and 25,239 NIC subjects). Between 1958 and 2009, there were 3.1 million person-years (PY) and 22,538 solid cancers for incidence analysis and 3.8 million PY and 15,419 solid cancer deaths for mortality analysis. We fitted sex-specific ERR models adjusted for smoking to both types of data. Over the entire range of doses, solid cancer mortality dose-response exhibited a borderline significant upward curvature among males (P = 0.062) and significant upward curvature among females (P = 0.010); for solid cancer incidence, as before, we found a significant upward curvature among males (P = 0.001) but not among females (P = 0.624). The sex difference in magnitude of dose-response curvature was statistically significant for cancer incidence (P = 0.017) but not for cancer mortality (P = 0.781). The results of analyses in the 0-2 Gy range and restricted lower dose ranges generally supported inferences made about the sex-specific dose-response shape over the entire range of doses for each outcome. Patterns of sex-specific curvature by calendar period (1958-1987 vs. 1988-2009) and age at exposure (0-19 vs. 20-83) varied between mortality and incidence data, particularly among females, although for each outcome there was an indication of curvature among 0-19-year-old male survivors in both calendar periods and among 0-19-year-old female survivors in the recent period. Collectively, our findings indicate that the upward curvature in all solid cancer dose response in the LSS is neither specific to males nor to incidence data; its evidence appears to depend on the composition of sites comprising all solid cancer group and age at exposure or time. Further follow up and site-specific analyses of cancer mortality and incidence will be important to confirm the emerging trend in dose-response curvature among young survivors and unveil the contributing factors and sites.

Fermented and nonfermented soy foods and the risk of breast cancer in a Japanese population-based cohort study

Background

Although preclinical studies suggest that fermented soy foods may have a protective effect against breast cancer, no prospective cohort studies have examined this association.

Objective

Our study examined the association between fermented and nonfermented soy food intake and breast cancer risk using a population‐based prospective cohort study in Japan.

Methods

We included a total of 47,614 women aged 45–74 years in an analysis of the Japan Public Health Center‐based Prospective Study (JPHC Study). A validated food frequency questionnaire (FFQ) was used for the assessment of dietary intake. Breast cancer incidence was analyzed by multivariate Cox proportional hazards regression models.

Results

During an average of 15.5 years of follow‐up, 825 breast cancer cases were newly identified. We found no association of intake of soy foods with breast cancer risk, regardless of fermentation, with multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for the highest quartiles of fermented and nonfermented soy food intake of 0.94 (0.67, 1.32) and 1.15 (0.85, 1.57) compared with the lowest quartile (p for trend = 0.305 and 0.393). Unlike nonfermented soy, higher intake of fermented soy foods was associated with a significant decrease in the risk of nonlocalized breast cancer. The HR and 95% CI in the highest compared to lowest intake category of fermented soy foods was 0.53 (0.28, 0.99) versus nonfermented soy foods 0.85 (0.51, 1.42) (p for trend = 0.026 and 0.797).

Conclusions

Our analyses showed that fermented soy foods had no association with overall breast cancer but may be associated with decreased risk of nonlocalized breast cancer.

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular risk-changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.

National trends in total cholesterol obscure heterogeneous changes in HDL and non-HDL cholesterol and total-to-HDL cholesterol ratio: a pooled analysis of 458 population-based studies in Asian and Western countries

BACKGROUND

Although high-density lipoprotein (HDL) and non-HDL cholesterol have opposite associations with coronary heart disease, multi-country reports of lipid trends only use total cholesterol (TC). Our aim was to compare trends in total, HDL and non-HDL cholesterol and the total-to-HDL cholesterol ratio in Asian and Western countries.

METHODS

We pooled 458 population-based studies with 82.1 million participants in 23 Asian and Western countries. We estimated changes in mean total, HDL and non-HDL cholesterol and mean total-to-HDL cholesterol ratio by country, sex and age group.

RESULTS

Since ∼1980, mean TC increased in Asian countries. In Japan and South Korea, the TC rise was due to rising HDL cholesterol, which increased by up to 0.17 mmol/L per decade in Japanese women; in China, it was due to rising non-HDL cholesterol. TC declined in Western countries, except in Polish men. The decline was largest in Finland and Norway, at ∼0.4 mmol/L per decade. The decline in TC in most Western countries was the net effect of an increase in HDL cholesterol and a decline in non-HDL cholesterol, with the HDL cholesterol increase largest in New Zealand and Switzerland. Mean total-to-HDL cholesterol ratio declined in Japan, South Korea and most Western countries, by as much as ∼0.7 per decade in Swiss men (equivalent to ∼26% decline in coronary heart disease risk per decade). The ratio increased in China.

CONCLUSIONS

HDL cholesterol has risen and the total-to-HDL cholesterol ratio has declined in many Western countries, Japan and South Korea, with only a weak correlation with changes in TC or non-HDL cholesterol.

How do cardiovascular diseases harm labor force participation? Evidence of nationally representative survey data from Japan, a super-aged society

OBJECTIVE

To evaluate how cardiovascular diseases harm labor force participation (LFP) among the Japanese population and verify the validity of plasma biomarkers as instrumental variables of cardiovascular diseases after adjusting for a broad set of confounders including dietary intake.

DESIGN

Using nationally representative repeated cross-sectional surveys in Japan, the Comprehensive Survey of Living Conditions and National Health and Nutrition Survey, with plasma biomarkers as instrumental variables for quasi-randomization.

SETTING

Onset of cardiovascular diseases in those receiving regular treatment for hypertension, intracerebral hemorrhage, intracerebral infarction, angina pectoris, myocardial infarction, or other types of cardiovascular diseases.

PARTICIPANTS

A total of 65,615 persons aged ≥ 20 years (35,037 women and 30,578 men) who completed a survey conducted every three years from 1995 through 2013.

MAIN OUTCOME MEASURES

Respondent employment and weekly working hours during each survey year.

RESULTS

Cardiovascular diseases significantly and remarkably reduced the probability of working by 15.4% (95% CI: -30.6% to -0.2%). The reduction in working probability was detected for women only. Respondents aged ≥ 40 years were less likely to work once diagnosed and the reduction was enlarged for those aged ≥ 65 years, while those aged < 40 years appeared to be unaffected. Probability of engaging in manual labor significantly decreased once diagnosed; however, no impact was found for cognitive occupations. Among employed respondents, the adverse effects of cardiovascular diseases decreased working hours by five hours per week. Validity of the biomarker instrumental variables was generally verified.

CONCLUSIONS

A vicious circle is suggested between LFP and unfavorable health. However, the effects vary across age, sex, and occupation type, even after adjusting for causal effects, which could cause a downward bias in LFP impact.

ATTRIBUTES

cardiovascular disease, labor force participation, instrumental variable method as quasi-randomization, plasma biomarker, Comprehensive Survey of Living Conditions, National Health and Nutrition Survey.

Cardiovascular Risk Assessment Chart by Dietary Factors in Japan - NIPPON DATA80

BACKGROUND

Many studies show that dietary factors such as vegetables, fruit, and salt are associated with cardiovascular disease (CVD) risk. However, a risk assessment chart for CVD mortality according to combinations of dietary factors has not been established.Methods and Results:Participants were 9,115 men and women aged 30-79 years enrolled in the National Nutritional Survey of Japan in 1980 with a 29-year follow-up. Dietary intake was assessed using a 3-day weighed dietary record at baseline. Cox regression models were used to estimate the hazard ratio (HR) of CVD mortality stratified by vegetables, fruit, fish, and salt consumption. HRs of CVD mortality according to combinations of dietary factors were color coded on an assessment chart. Higher intakes of vegetables, fruit, and fish, and lower salt intake were associated with lower CVD mortality risk. HRs calculated from combinations of dietary factors were displayed using 5 colors corresponding to the magnitude of the HR. People with the lowest intake of vegetables, fruit, and fish, and higher salt intake had a HR of 2.87 compared with those with the highest intake of vegetables, fruit, and fish, and lower salt intake.

CONCLUSIONS

Vegetables, fruit, fish, and salt intake were independently associated with CVD mortality risk. The assessment chart generated could be used in Japan as an educational tool for CVD prevention.

Effects of rapid aging and lower participation rate among younger adults on the short-term trend of physical activity in the National Health and Nutrition Survey, Japan

AIM

The National Health and Nutrition Survey, Japan, has annually monitored two indicators of physical activity in adults. They are contrasting in the association with age; the prevalence of exercise habit is lower and step counts are higher among younger participants. The present study aimed to examine the effects of rapid aging of the Japanese population and the lower participation rate among younger adults on the short-term trend of two indicators of physical activity using tabulated data.

METHODS

The prevalence of exercise habit and step counts by age groups (≥20 years) from 2003 to 2010 were estimated using tabulated data from the National Health and Nutrition Survey by calculating sex-specific means weighted by age-specific Japanese population data for each year (population-weighted estimates) and for a fixed year (2005; age-standardized estimates). Linear regression analyses were used to test the statistical significance of their trends.

RESULTS

Statistically significant increasing trends in the prevalence of exercise habit were observed for the crude means (P = 0.029), the population-weighted estimates (P = 0.007) and the age-standardized estimates (P = 0.016) only in men. Statistically significant decreasing trends in the step counts were observed for the crude means (P = 0.006 in men and P = 0.033 in women) and the population-weighted estimates (P = 0.008 in men and P = 0.049 in women) both in men and women, but for the age-standardized estimates (P = 0.039) only in men.

CONCLUSIONS

The effects of rapid aging of the Japanese population and the lower participation rate among younger adults on the short-term trend are not small, and age-standardization is necessary to observe even the short-term trend of physical activity data. Geriatr Gerontol Int 2017; 17: 1677-1682.

Providing prostate cancer survivorship care in Japan: Implications from the USA care model

Despite an increasing number of prostate cancer survivors in Japan, the current delivery of prostate cancer survivorship care is insufficient and lacks a multidisciplinary approach. We carried out a study to characterize prostate cancer survivorship care in Japan, examine the Japanese workforce available to deliver survivorship care, introduce a conceptual framework for survivorship and identify opportunities to improve Japanese survivorship care. We systematically searched PubMed for prostate cancer survivorship care studies, including those from Japan. We also searched the internet for prostate cancer guidelines relevant to survivorship care. We found 392 articles, of which 71 were relevant, read in detail and reported here. In Japan, survivorship care is mostly provided by urologists. Primary care as a specialty does not exist in Japan, and there are no independent nurse practitioners or physician assistants to assist with survivorship care. Japanese quality of life studies characterize the long-term effects of prostate cancer treatment, but routine use of patient-reported outcomes is not common in Japan. In the USA, in light of a growing comprehensive awareness of challenges facing survivors and their providers, the American Cancer Society prostate cancer survivorship care guidelines serve as a tool for optimizing the management of long-term treatment effects and coordination of care. In order to deliver high-quality survivorship care in Japan, urologists need to establish collaborations with other disciplines within the delivery system. A multidisciplinary guideline for prostate cancer survivorship care in Japan appears warranted.

Dairy products intake and cancer mortality risk: a meta-analysis of 11 population-based cohort studies

BACKGROUND

Dairy products are major components of daily diet and the association between consumption of dairy products and public health issues has captured great attention. In this study, we conducted a meta-analysis to investigate the association between dairy products intake and cancer mortality risk.

METHODS

After a literature search in PubMed and EMBASE, 11 population-based cohort studies involving 778,929 individuals were considered eligible and included in the analyses. Data were extracted and the association between dairy products intake and cancer mortality risk was estimated by calculating pooled relative risks (RRs) and corresponding 95 % confidence intervals (CIs). Sensitivity analyses and subgroup analyses based on regions, genders and dairy types were performed as well. Potential dose-response relationship was further explored by adopting the generalized least squares (GLST) method.

RESULTS

Total dairy products intake was not associated with all cancer mortality risk, with the pooled RR of 0.99 (95 % CI 0.92-1.07, p = 0.893). Subgroup analyses showed that the pooled RRs were 0.97 (95 % CI 0.92-1.03, p = 0.314) for milk, 0.88 (95 % CI 0.71-1.10, p = 0.271) for yogurt, 1.23 (95 % CI 0.94-1.61, p = 0.127) for cheese and 1.13 (95 % CI 0.89-1.44, p = 0.317) for butter in male and female, however the pooled RR was 1.50 (95 % CI 1.03-2.17, p = 0.032) for whole milk in male, which was limited to prostate cancer. Further dose-response analyses were performed and we found that increase of whole milk (serving/day) induced elevated prostate cancer mortality risk significantly, with the RR of 1.43 (95 % CI 1.13-1.81, p = 0.003).

CONCLUSIONS

Total dairy products intake have no significant impact on increased all cancer mortality risk, while low total dairy intake even reduced relative risk based on the non-linear model. However, whole milk intake in men contributed to elevated prostate cancer mortality risk significantly. Furthermore, a linear dose-response relationship existed between increase of whole milk intake and increase of prostate cancer mortality risk.

Continuous decline in mortality from coronary heart disease in Japan despite a continuous and marked rise in total cholesterol: Japanese experience after the Seven Countries Study

BACKGROUND

The Seven Countries Study in the 1960s showed very low mortality from coronary heart disease (CHD) in Japan, which was attributed to very low levels of total cholesterol. Studies of migrant Japanese to the USA in the 1970s documented increase in CHD rates, thus CHD mortality in Japan was expected to increase as their lifestyle became Westernized, yet CHD mortality has continued to decline since 1970. This study describes trends in CHD mortality and its risk factors since 1980 in Japan, contrasting those in other selected developed countries.

METHODS

We selected Australia, Canada, France, Japan, Spain, Sweden, the UK and the USA. CHD mortality between 1980 and 2007 was obtained from WHO Statistical Information System. National data on traditional risk factors during the same period were obtained from literature and national surveys.

RESULTS

Age-adjusted CHD mortality continuously declined between 1980 and 2007 in all these countries. The decline was accompanied by a constant fall in total cholesterol except Japan where total cholesterol continuously rose. In the birth cohort of individuals currently aged 50-69 years, levels of total cholesterol have been higher in Japan than in the USA, yet CHD mortality in Japan remained the lowest: >67% lower in men and > 75% lower in women compared with the USA. The direction and magnitude of changes in other risk factors were generally similar between Japan and the other countries.

CONCLUSIONS

Decline in CHD mortality despite a continuous rise in total cholesterol is unique. The observation may suggest some protective factors unique to Japanese.

Contributions of risk factors and medical care to cardiovascular mortality trends

Ischaemic heart disease, stroke, and other cardiovascular diseases (CVDs) lead to 17.5 million deaths worldwide per year. Taking into account population ageing, CVD death rates are decreasing steadily both in regions with reliable trend data and globally. The declines in high-income countries and some Latin American countries have been ongoing for decades without slowing. These positive trends have broadly coincided with, and benefited from, declines in smoking and physiological risk factors, such as blood pressure and serum cholesterol levels. These declines have also coincided with, and benefited from, improvements in medical care, including primary prevention, diagnosis, and treatment of acute CVDs, as well as post-hospital care, especially in the past 40 years. These variables, however, explain neither why the decline began when it did, nor the similarities and differences in the start time and rate of the decline between countries and sexes. In Russia and some other former Soviet countries, changes in volume and patterns of alcohol consumption have caused sharp rises in CVD mortality since the early 1990s. An important challenge in reaching firm conclusions about the drivers of these remarkable international trends is the paucity of time-trend data on CVD incidence, risk factors throughout the life-course, and clinical care.

Seasonal differences in total antioxidant capacity intake from foods consumed by a Japanese population

BACKGROUND/OBJECTIVES

This cross-sectional study aimed to estimate total antioxidant capacity (TAC) intake from food and beverages in a Japanese population from 7-day seasonal dietary records.

SUBJECTS/METHODS

The 7-day weighed dietary records of 390 subjects over four seasons between 1996 and 1998 were used. The TAC values (μmol trolox equivalents (μmol TE)/g) of various foods and beverages were defined, as reported in previous studies for weighed dietary records, using several different methods. TAC values of foods were estimated in 242 food and beverage items: 86.5% of vegetables, 99.1% of fruits, 71.5% of potatoes, 96.7% of beans, and 100% of chocolates. Differences in TAC intake per day and intake (g) per day among seasons in each of the food and beverage group were compared using a general linear model for repeated measures. The TAC intake/day were calculated for each food and beverage item in the four seasons.

RESULTS

TAC intake/day (μmol TE/day) varied from 10 189 (summer) to 12 292 (winter). TAC intake/day from fruits (2696) and potatoes (395) was highest in autumn, from vegetables (2827) it was highest in summer and from beans (4151) and tea (2331) it was highest in winter.

CONCLUSIONS

The dietary habits of the studied Japanese population showed the highest antioxidant capacity in winter and the lowest in summer.

Descriptive epidemiological study of food intake among Japanese adults: analyses by age, time and birth cohort model

BACKGROUND

Although food and nutrient consumption among the Japanese population, known to have one of the longest life expectancies in the world, has changed markedly after World War II, little is known about the influences age, time and birth cohort have had. The present study examined the effects age, time and birth cohort have had on intake of 14 food groups from 1989 to 2009, using published data from the National Health and Nutrition Survey in Japan.

METHODS

The survey included 575 adults (271 men and 304 women) in 1989, 8431 (3952 men and 4479 women) in 1999 and 5632 (2629 men and 3003 women) in 2009. The effects of age on energy-adjusted food intakes defined by gender and birth cohort (birth in 1930-1939, 1940-1949, 1950-1959, 1960-1969, 1970-1979) were estimated using the mean polish process.

RESULTS

Intakes of meat and confectionary increased whereas those of milk and dairy products, sugar, and fats and oils decreased from 1989 to 2009. Both men and women in the 1940's birth cohort consumed more fruit, although differences in food intake by birth cohort were less discernible. Furthermore, meat, fats and oils, and wheat intake decreased while fruits, fish, beans and vegetables consumption increased with aging in both men and women.

CONCLUSIONS

The present analysis suggests intakes of meat and confectionary have increased in Japan over the past 20 years regardless of age and generation. Also, younger individuals are less likely to consume fruits, fish, beans and vegetables regardless of the birth cohort and time period. Differences in food group consumption by birth cohorts born between 1930 and 1979 were not obvious. The first indication of these findings would be that in order to avoid ongoing increases in meat and confectionery intake, the public health strategy should target the whole Japanese population. Secondly, intervening with the diet of younger individuals, especially today, would be reasonable as it is unknown whether today's younger individuals will adopt a healthier diet when they age as the other generations did.

Assessment of daily food and nutrient intake in Japanese type 2 diabetes mellitus patients using dietary reference intakes

Medical nutrition therapy for the management of diabetes plays an important role in preventing diabetes complications and managing metabolic control. However, little is known about actual eating habits of individuals with type 2 diabetic mellitus (T2DM), especially in Japan. Therefore, we sought to (1) assess the dietary intake of individuals with T2DM, and (2) characterize their intake relative to national recommendations. This cross-sectional study involved 149 patients (77 males and 72 females) aged 40-79 years with T2DM recruited at a Kyoto hospital. Dietary intake was assessed using a validated self-administered diet history questionnaire. Under-consumption, adequacy, and over-consumption, of nutrients were compared to the age- and sex-based standards of the Japanese Dietary Reference Intakes. Among the results, most notable are (1) the inadequacy of diets in men with respect to intake of vitamins and minerals, likely owing to low intake of vegetables and fruits; (2) excess contributions of fat intake to total energy in both sexes; and (3) excess consumption of sweets and beverages relative to the national average. The prevalence of diabetes complications may be increasing because of a major gap between the typical dietary intake of individuals with T2DM and dietary recommendation.

Involvement of inflammatory factors in pancreatic carcinogenesis and preventive effects of anti-inflammatory agents

Chronic inflammation is known to be a risk for many cancers, including pancreatic cancer. Heavy alcohol drinking and cigarette smoking are major causes of pancreatitis, and epidemiological studies have shown that smoking and chronic pancreatitis are risk factors for pancreatic cancer. Meanwhile, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are elevated in pancreatitis and pancreatic cancer tissues in humans and in animal models. Selective inhibitors of iNOS and COX-2 suppress pancreatic cancer development in a chemical carcinogenesis model of hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). In addition, hyperlipidemia, obesity, and type II diabetes are also suggested to be associated with chronic inflammation in the pancreas and involved in pancreatic cancer development. We have shown that a high-fat diet increased pancreatic cancer development in BOP-treated hamsters, along with aggravation of hyperlipidemia, severe fatty infiltration, and increased expression of adipokines and inflammatory factors in the pancreas. Of note, fatty pancreas has been observed in obese and/or diabetic cases in humans. Preventive effects of anti-hyperlipidemic/anti-diabetic agents on pancreatic cancer have also been shown in humans and animals. Taking this evidence into consideration, modulation of inflammatory factors by anti-inflammatory agents will provide useful data for prevention of pancreatic cancer.

The use of summary statistics for sample size allocation for food composition surveys and an application to the potato group

To give a quantitative guide to sample size allocation for developing sampling designs for a food composition survey, we discuss sampling strategies that consider the importance of each food; namely, consumption or production, variability of composition, and the restrictions within the available resources for sample collection and analysis are considered., Here we consider two strategies: 'proportional' and 'Neyman' are discussed. Both of these incorporate consumed quantity of foods, and we review some available statistics for allocation issues. The Neyman optimal strategy allocates less sample size for starch than proportional, because the former incorporates variability in the composition. Those strategies improved accuracy in dietary nutrient intake more than equal sample size allocation. Those strategies will be useful as we often face sample size allocation problems, wherein we decide whether to sample 'five white potatoes and five taros or nine white and one taros'. Allocating sufficient sample size for important foodstuffs is essential in assuring data quality. Nevertheless, the food composition table should be as comprehensive as possible.

Relationships between eating habits and periodontal condition in university students

BACKGROUND

Being overweight is a risk factor for periodontitis. Unhealthy eating habits, which can induce overweight, may be involved in the development of periodontitis in young people. The present study aims to examine the relationships among overweight, eating habits, and the periodontal condition in Japanese university students.

METHODS

We conducted a cross-sectional study of 801 university students (413 males and 388 females; age range: 18 to 25 years). Patients were classified as underweight (body mass index [BMI] <18.5 kg/m(2)), normal weight (BMI of 18.5 to 22.9 kg/m²), and overweight (BMI ≥ 23 kg/m²). Students completed a questionnaire including items related to eating habits and underwent oral health examinations. Patients with a community periodontal index (CPI) of 0 to 2 were considered controls, and patients with a CPI >2 were considered to have periodontitis.

RESULTS

The prevalence of underweight, normal weight, and overweight patients was 21%, 62%, and 17%, respectively. In overweight patients, the periodontitis risk was increased by the frequent consumption of fatty foods (adjusted odds ratio: 2.3; 95% confidence interval: 1.1 to 5.2; P <0.05) and reduced by the frequent consumption of vegetables (adjusted odds ratio: 0.2; 95% confidence interval: 0.1 to 0.7; P <0.01). In underweight and normal-weight groups, eating habits did not differ significantly according to the presence of periodontitis.

CONCLUSIONS

In overweight students, the frequent consumption of fatty foods and infrequent consumption of vegetables were associated with an increased risk of periodontitis. In underweight and normal-weight students, eating habits had little effect on the periodontal condition.

Gastroesophageal reflux disease in Asia: A historical perspective and present challenges

Gastroesophageal reflux disease (GERD), previously uncommon in Asia, has now become an important disease in the region. Although much variability exists between studies, most endoscopy-based studies show a prevalence of erosive esophagitis of more than 10%. Symptom-based studies also show a prevalence of 6-10%. Two longitudinal follow-up studies on GERD symptoms have shown an increase with time, and several endoscopy-based time trend studies have also shown a significant increase in erosive reflux esophagitis. Studies on Barrett's esophagus have been confounded by the description of short (SSBE) and long segment (LSBE) Barrett's esophagus. Great variation in prevalence rates has been reported. SSBE vary from 0.1% to more than 20% while LSBE vary from 1-2%. Of the putative causative factors, obesity has been the most important. Many studies have linked GERD-esophagitis as well as occurrence of reflux symptoms with an increase in body mass index (BMI), obesity, especially visceral or central obesity, and metabolic syndrome. A decline in Helicobacter pylori infection with growing affluence in Asia has been broadly thought to result in healthier stomachs and a higher gastric acid output resulting in reflux disease. However, variable results have been obtained from association and H. pylori eradication studies.

Iron intake and associated factors in general Japanese population: NIPPON DATA80, NIPPON DATA90 and national nutrition monitoring

OBJECTIVE

The purpose of this study was to investigate the dietary iron intake and associated other dietary factors and clinical characteristics among a representative sample cohort of Japanese population.

METHODS

We obtained data from NIPPON DATA80 and 90 that were conducted with the National Nutrition Surveys in 1980 and in 1990. Then we estimated nutrient and food intakes of individuals in the National Nutrition Survey of 1980 and that of 1990, which were adjusted on the basis of data of the National Nutrition Survey of 1995. Finally, we analyzed data for the 10,422 participants (4585 men and 5837 women) in NIPPON DATA80 and 8342 participants (3488 men and 4854 women) in NIPPON DATA90 having dietary iron intake information.

RESULTS

In NIPPON DATA80 and 90, there was a significant relationship between the dietary iron intake and age for both men and women. Dietary protein intake was associated with iron intake where as dietary fat intake did not show any association. Regarding the minerals, significant relationships were observed between the different minerals and dietary iron intake. Apart from the food group of milk and dairy products, there were significant differences in other food groups according to quintiles of iron intakes for men and women.

CONCLUSIONS

We described the mean dietary iron intake and its relation with other dietary factors and clinical characteristics in Japanese adults as the baseline data in NIPPON DATA80 and in NIPPON DATA90.

Comparison of the National Nutritional Survey in Japan estimated individual-based nutritional data and NIPPON DATA80 food frequency questionnaires

Background

The National Nutritional Survey in Japan (NNSJ) was initiated in 1946. Using the majority of the participants for NNSJ, the National Survey on Circulatory Disorders has been conducted every 10 year since 1960. We performed a comparative study of the NNSJ80 estimated individual-based nutritional data by comparing those with NIPPON DATA80 food frequency questionnaires (FFQ) data.

Methods

A total of 10 546 community residents from 300 randomly selected districts participated in the both surveys in 1980. At baseline, history, physical, and blood biochemical measurement and a nutritional survey by FFQ were performed individually. From household-based NNSJ80 data, we estimated nutrient intakes of each household member by dividing household intake data proportionally using average intakes by sex and age groups calculated for NNSJ95. We re-categorized NNSJ80 estimated data to correspond to NIPPON DATA80 FFQ categories. Data were analyzed in men and women separately.

Results

Cross tables showed fairly good agreement of the two categories. The majorities of participants situated on the diagonally aligned cells or the next to them. Weighted kappa ranged from 0.152 to 0.241. Spearman’s rank correlation coefficients between the two categories ranged from 0.224 to 0.338, and those between NNSJ80 continuous data and NIPPON DATA80 categorical data ranged from 0.237 to 0.354. All these values have P < 0.001.

Conclusions

These results may indicate that the present nutritional estimation method is applicable to, further studies.

Dietary salt intake and blood pressure in a representative Japanese population: baseline analyses of NIPPON DATA80

Background

The relationship between dietary salt intake and blood pressure (BP) has been rarely investigated in a large population of Japanese. The characteristics of nutrients intake and foods intake in Japanese people with high salt intake have also not investigated well.

Methods

Data of 10 422 participants (4585 men and 5837 women) aged 30 or older who participated in both the National Survey on Circulatory Disorders and National Nutrition Survey in Japan conducted in 1980 were used. The nutrition surveys were performed with weighing record method for three consecutive days to each household. BP and intakes of nutrients and foods were compared by the quintiles of estimated individual salt intake per day. Analyses of covariance were used to calculate multivariate-adjusted mean BP values by the quintiles.

Results

Participants with higher salt intake showed higher intakes of soy beans/legume, fruit, other vegetables, and fish/shellfish. Intakes of protein, potassium, calcium, iron, magnesium, and fiber were higher in higher quintiles of salt intake. In men, adjusted systolic BPs were higher in the higher salt intake quintiles; there was 4.3 mm Hg difference in multivariate-adjusted systolic BP between the lowest quintile (mean salt intake 8.7 g/day) and the highest quintile (mean salt intake 23.5 g/day) (P < 0.001). In women, adjusted mean systolic BPs were not statistically different among the quintile of salt intake.

Conclusions

A positive relationship of dietary salt intake to BP was observed, especially in men, in this large-scale representative Japanese population.

Fatty acids intakes and serum lipid profiles: NIPPON DATA90 and the national nutrition monitoring

Background

The National Nutritional Survey in Japan (NNSJ) was initiated in 1946. Using the majority of the participants for NNSJ, the National Survey on Circulatory Disorders (NSCD) has been conducted every 10 year since 1960. We compared fatty acids intakes obtained from NNSJ and serum lipid profiles from NSCD conducted in 1990.

Methods

A total of 8344 community residents (4856 women and 3488 men, age ≥ 30) from 300 randomly selected districts participated in the both surveys in 1990. At baseline, history, physical, and blood biochemical measurement and a nutritional survey were performed. We estimated nutrient intakes of each household member by dividing household intake data proportionally using average intakes by sex and age groups calculated for NNSJ95.

Results

Total fat, saturated fatty acids (SFA), poly-unsaturated fatty acids (PUFA), dietary cholesterol, and Keys dietary lipid factor (KEYS) were inversely associated with age in both men and women (all Ps < 0.001). In women, age and body mass index (BMI) adjusted serum total cholesterol (TC), high-density lipoprotein cholesterol (HDLc), and low-density lipoprotein cholesterol (LDLc) were positively associated with SFA, total fat intakes (%kcal), and with KEYS (P < 0.001). In men, age-BMI adjusted HDLc was not associated with SFA, total fat intakes, and with KEYS factors unlike in women. Other associations were similar to those in women.

Conclusions

The total fatty acids, SFA intakes, and KEYS lipid factor obtained from NNSJ were significantly associated with serum total and LDL cholesterol from the National Survey on Circulatory Disorders conducted in 1990.

[Reflection about Japanese immigration to Brazil under the light of body adiposity]

Migrant populations represent a good opportunity to investigate the role of environmental factors for the genesis of obesity and its comorbidities. The Japanese-Brazilian Diabetes Study Group studied the prevalence of diabetes and related disorders in Japanese-Brazilians from Bauru, SP, in 1993. Using specific criteria for Asian, 22.4% of the Japanese-Brazilians were found as having overweight in this first phase of the study. In the second phase, in 2000, this prevalence increased to 44.2% and 50.3% had central obesity. This population also had high prevalence of type 2 diabetes, hypertension and dyslipidemia, components of the metabolic syndrome. The JBDS Group also showed the association between Occidentalized habits, mainly a rich saturated-fat-diet, and the occurrence of the metabolic syndrome. In 2005, motivated by these findings, the JBDS Group started the third phase of the study which was an intervention program based on healthy diet and physical activity recommendations, using resources that could be feasible in terms of public health in Brazil. After one year-intervention program, the JBDS Group observed a decrease in anthropometric parameters, blood pressure and plasma glucose and cholesterol levels. It will be necessary a longer follow-up to evaluate the maintainance of these benefits and their impact in the risk development of diabetes and cardiovascular events.

Dietary intake of potassium and associated dietary factors among representative samples of Japanese general population: NIPPON DATA 80/90

OBJECTIVE

The purpose of this study was to investigate the dietary potassium intake and associated other dietary factors among a representative sample cohort of Japanese population.

METHODS

We obtained data from NIPPON DATA80 and 90 that were conducted with the National Nutrition Surveys in 1980 and in 1990. Then we estimated nutrient and food intakes of individuals in the National Nutrition Survey of 1980 and that of 1990, which were adjusted on the basis of data of the National Nutrition Survey of 1995. We analyzed data for 10,422 participants (4585 men and 5837 women) in NIPPON DATA80 and 8342 participants (3488 men and 4854 women) in NIPPON DATA90 having dietary potassium intake information.

RESULTS

In NIPPON DATA80 and 90 it was observed that there was a significant relationship between the dietary potassium intake and age for both men and women. Higher potassium intake was associated with higher age, intake of protein, iron, calcium, sodium, vitamins, and fiber. Regarding food groups, lower amount of dietary cereals, rice, flour, fats and oils were associated with higher dietary potassium for both men and women. On the other hand, higher intake of nuts, potatoes, soy beans, fruits, vegetables, mushrooms, sea algae, fish and shellfish were associated with higher dietary potassium.

CONCLUSIONS

We obtained the mean dietary potassium intake and its association with other dietary nutrient intake in Japanese adults as the baseline data in NIPPON DATA80 and in NIPPON DATA90.

Integration of data from NIPPON DATA80/90 and National Nutrition Survey in Japan: for cohort studies of representative Japanese on nutrition

BACKGROUND

Diet is one of the most important lifestyle factors that a affect healthy life expectancy through onset of various lifestyle-related diseases. Large-scale cohort studies with sufficient baseline nutritional information are scarce. NIPPON DATA80/90 is cohort study of representative Japanese population, and the cohorts also participated in the National Nutrition Survey in Japan (NNSJ) at the baseline. The corresponding datasets could be combined.

METHODS

Individual records of NIPPON DATA and NNSJ were compared and integrated. Intakes of nutrients and food groups for individual participants were calculated by distributing intakes in the each household in NNSJ, considering age and sex of the individuals. The results from an international cooperative epidemiological study (INTERMAP) were utilized to estimate intakes of 75 nutrients for NNSJ80 and 70 nutrients for NNSJ90. Nutrient intakes calculated utilizing INTERMAP data were compared with those in the NNSJ datasets.

RESULTS

NIPPON DATA80/90 datasets were enhanced with detailed baseline nutrient intake data (the numbers of participants combined were 10,422 and 8342 for NIPPON DATA80 and 90, respectively). The mean nutrient intakes calculated through utilizing INTEMRAP data and those calculated from the NNSJ datasets were similar, and the calculated values were strongly correlated with those calculated from NNSJ datasets (Pearson's correlation coefficients greater than 0.8 [P < 0.001]). Detailed nutrient intakes (eg, cholesterol, fatty acids, amino acids, and dietary fiber) were complemented.

CONCLUSIONS

The nutrient intakes calculated from NNSJ datasets for the participants of NIPPON DATA are appropriate as the baseline nutrient intake data. The enhanced cohort datasets are suitable for investigations of baseline dietary habits and the consequent health status.

Postmenopausal breast cancer risk and dietary patterns in the E3N-EPIC prospective cohort study

Since evidence relating diet to breast cancer risk is not sufficiently consistent to elaborate preventive proposals, the authors examined the association between dietary patterns and breast cancer risk in a large French cohort study. The analyses included 2,381 postmenopausal invasive breast cancer cases diagnosed during a median 9.7-year follow-up period (1993-2005) among 65,374 women from the E3N-EPIC cohort. Scores for dietary patterns were obtained by factor analysis, and breast cancer hazard ratios were estimated by Cox proportional hazards regression for the highest quartile of dietary pattern score versus the lowest. Two dietary patterns were identified: "alcohol/Western" (essentially meat products, French fries, appetizers, rice/pasta, potatoes, pulses, pizza/pies, canned fish, eggs, alcoholic beverages, cakes, mayonnaise, and butter/cream) and "healthy/Mediterranean" (essentially vegetables, fruits, seafood, olive oil, and sunflower oil). The first pattern was positively associated with breast cancer risk (hazard ratio = 1.20, 95% confidence interval (CI): 1.03, 1.38; P = 0.007 for linear trend), especially when tumors were estrogen receptor-positive/progesterone receptor-positive. The "healthy/Mediterranean" pattern was negatively associated with breast cancer risk (hazard ratio = 0.85, 95% CI: 0.75, 0.95; P = 0.003 for linear trend), especially when tumors were estrogen receptor-positive/progesterone receptor-negative. Adherence to a diet comprising mostly fruits, vegetables, fish, and olive/sunflower oil, along with avoidance of Western-type foods, may contribute to a substantial reduction in postmenopausal breast cancer risk.

Changes in body mass index by birth cohort in Japanese adults: results from the National Nutrition Survey of Japan 1956-2005

Background The National Nutrition Survey, Japan (NNS-J) provides annual anthropometric information for a whole nation over 50 years. Based on this survey, the mean body mass index (BMI) of Japanese men and elderly women has increased in recent decades, but that of young women has decreased. We examined the effect of birth cohort on this phenomenon.

Methods We analysed data from the NNS-J for subjects aged 20–69 years. BMI during 1956–2005 and the prevalence of overweight and obesity (BMI ≥ 25 kg/m²) during 1976–2005 were estimated.

Results The BMI increased with age in every birth cohort, with similar increments, and did not peak until 60–69 years of age. However, with cross-sectional age, the BMI usually peaked before 60–69 years of age. The differences among cohorts already existed at 20–29 years of age, and slightly increased in men between 20–29 and 30–39 years of age. The BMI in all male age groups increased from the 1891–1900 through 1971–80 cohorts. However, in women, the figure increased until the 1931–40 cohorts, but later decreased. Changes in prevalence were generally consistent with changes in BMI. The recent increase (decrease in young women) in the mean BMI is attributable to birth cohort, indicating that thinner (fatter) and less recent birth cohorts have been replaced by fatter (thinner) ones.

Conclusions A cohort effect was quantitatively demonstrated based on a repeated annual survey. In Japan, the differences in BMI among cohorts were already established by young adulthood.

Do overweight children necessarily make overweight adults? Repeated cross sectional annual nationwide survey of Japanese girls and women over nearly six decades

OBJECTIVE

To compare growth curves of body mass index from children to adolescents, and then to young adults, in Japanese girls and women in birth cohorts born from 1930 to 1999.

DESIGN

Retrospective repeated cross sectional annual nationwide surveys (national nutrition survey, Japan) carried out from 1948 to 2005.

SETTING

Japan.

PARTICIPANTS

76,635 females from 1 to 25 years of age.

MAIN OUTCOME MEASURE

Body mass index.

RESULTS

Generally, body mass index decreased in preschool children (2-5 years), increased in children (6-12 years) and adolescents (13-18 years), and slightly decreased in young adults (19-25 years) in these Japanese females. However, the curves differed among birth cohorts. More recent cohorts were more overweight as children but thinner as young women. The increments in body mass index in early childhood were larger in more recent cohorts than in older cohorts. However, the increments in body mass index in adolescents were smaller and the decrease in body mass index in young adults started earlier, with lower peak values in more recent cohorts than in older cohorts. The decrements in body mass index in young adults were similar in all birth cohorts.

CONCLUSIONS

An overweight birth cohort in childhood does not necessarily continue to be overweight in young adulthood. Not only secular trends in body mass index at fixed ages but also growth curves for wide age ranges by birth cohorts should be considered to study obesity and thinness. Growth curves by birth cohorts were produced by a repeated cross sectional annual survey over nearly six decades.

Metabolic improvement of male prisoners with type 2 diabetes in Fukushima Prison, Japan

Imprisonment often improves metabolic control in prisoners with type 2 diabetes; however, the reasons for this remain unclear. Here, we investigated the metabolic control of male prisoners with type 2 diabetes in Japan. Retrospective analysis of 4385 medical charts of male prisoners in Fukushima Prison from 1998 to 2004 revealed 109 prisoners (all Asian) with type 2 diabetes (mean+/-S.D.: 51+/-10 years). All were followed up during their imprisonment (14+/-10 months). During imprisonment, mean fasting plasma glucose and hemoglobin Alc (HbA1c) levels dramatically decreased from 184+/-74 to 113+/-38mg/dl (p<0.001) and 8.4+/-2.1 to 5.9+/-1.2% (p<0.001), respectively. In addition, 5 of 18 prisoners (28%) treated with insulin and 17 of 34 (50%) treated with oral hypoglycemic agents were able to discontinue their treatment and maintain good metabolic control. Most prisoners in Japanese prisons work 8h a day 5 days a week, consuming a high dietary fiber diet including boiled rice with barley, "Mugimeshi". These findings suggest that a well-regulated lifestyle and long-term intake of high dietary fiber may have beneficial effects on metabolic control in patients with type 2 diabetes.

Epidemic obesity and type 2 diabetes in Asia

The proportions of people with type 2 diabetes and obesity have increased throughout Asia, and the rate of increase shows no sign of slowing. People in Asia tend to develop diabetes with a lesser degree of obesity at younger ages, suffer longer with complications of diabetes, and die sooner than people in other regions. Childhood obesity has increased substantially and the prevalence of type 2 diabetes has now reached epidemic levels in Asia. The health consequences of this epidemic threaten to overwhelm health-care systems in the region. Urgent action is needed, and advocacy for lifestyle changes is the first step. Countries should review and implement interventions, and take a comprehensive and integrated public-health approach. At the level of primary prevention, such programmes can be linked to other non-communicable disease prevention programmes that target lifestyle-related issues. The cost of inaction is clear and unacceptable.

Long-term compliance with salt restriction in Japanese hypertensive patients

The purpose of the present study was to investigate the long-term compliance with salt restriction in Japanese hypertensive patients. Subjects included 389 patients, 230 women and 159 men, mean age 58+/-11 years, who underwent successful 24-h home urine collection more than three times over an interval of a year. Urinary salt, potassium, and creatinine were measured. Additionally, family history, habitual alcohol intake, smoking habit, physical activities, and job status were assessed by use of a questionnaire. During the follow-up period (average 3.5 years), participants underwent urine collection 4.6 times in average. Urinary salt excretion at the last visit was significantly lower than that at the first visit (8.7+/-3.4 vs. 9.6+/-4.1 g/day; p<0.01). Urinary potassium excretion also decreased significantly during this period (from 2.0+/-0.7 to 1.9+/-0.7 g/day; p<0.05). Among the mean 4.6 urine collections, 45.2% (men 34.6%, women 52.6%) of the patients successfully achieved <6 g (100 mmol of sodium)/day of salt excretion on at least one occasion. The rate of achievement of averaged urinary salt excretion <6 g/day dropped to 10.3% (men 4.4%, women 14.3%). Only 2.3% (men 0.6%, women 3.5%) of the patients achieved <6 g/day on all occasions. There were no significant differences in age, habitual alcohol intake, smoking habit, physical activities, or job status between patients who complied with the salt-restricted diet and those who did not. Results suggest that long-term compliance with salt restriction is poor in Japanese hypertensive patients. Since no specifically defining characteristics were found in the compliant patients, repeated measurements of urinary salt excretion seem to be important to encourage salt restriction.

A comparative study of food habits and body shape perception of university students in Japan and Korea

Background

Abnormal body weight, dietary concerns, and unhealthy weight loss behaviors are increasingly being observed in young females in Japan. Our previous research has shown that the irregular lifestyles of female Japanese and Chinese students are significantly related to their desire to be thinner. In the present study, we compare the food habits and body shape preferences of female university students in South Korea and Japan to explore body shape perceptions in those populations.

Methods

A total of 265 female university students aged 19 – 25 years participated in this study. University students in Korea (n = 141) and university students in Japan (n = 124) completed a self-reported questionnaire. Data were analyzed using SPSS statistical software. Descriptive statistics were used to identify the demographic characteristics of the students and parametric variables were analyzed using the Student's t-test. Chi-square analyses were conducted for non-parametric variables.

Results

Comparison of body mass index (BMI) distributions in Japan and Korea showed the highest value in the normal category (74%) together with a very low obesity rate (1.2%). Significant differences were observed between the two countries in terms of eating patterns, with more Japanese eating breakfast daily and with Japanese students eating meals more regularly than Korean students. A difference was also observed in frequency of meals, where Korean students reported eating meals two times per day (59%) and the majority of Japanese students reported eating meals three times per day (81%). Although most subjects belonged to the normal BMI category, their ideal BMI classification was the underweight category (BMI: 18.4 ± 3.4).

Conclusion

Few studies have compared the health related practices of Japanese and Korean university students. The present results suggest the necessity of nutrition and health promotion programs for university students, especially programs emphasizing weight management.

A controlled 2-mo dietary fat reduction and soy food supplementation study in postmenopausal women

BACKGROUND

Low intake of dietary fat and high intake of soy foods have been suggested to partly explain the lower breast cancer rates in Asia, perhaps because of lower endogenous estrogens.

OBJECTIVE

The objective was to assess the hormonal and nonhormonal effects of diets resembling an Asian diet in terms of total fat and soy food contents.

DESIGN

Fifty-seven postmenopausal women participated in a randomized, controlled, dietary intervention study. The subjects consumed a very-low-fat diet (VLFD; 11% of energy as fat), a Step I diet (25% of energy as fat) supplemented with soy food (SFD; 50 mg isoflavones/d), or a control Step I diet (CD; 27% of energy as fat) with no soy food. All diets were prepared at the General Clinical Research Center of the University of Southern California. Serum hormones and other markers were measured at baseline and every 2 wk during the 8 wk of intervention.

RESULTS

There were no significant differences in total estradiol and sex hormone binding globulin at the completion of the intervention between women in the SFD and VLFD groups and those in the CD group. Serum insulin decreased significantly in the SFD group, and leptin decreased significantly in the SFD and VLFD groups; however, these changes did not differ significantly from the changes in the CD group.

CONCLUSIONS

This study does not provide evidence that ingestion of soy food or a VLFD significantly reduces estrogen concentrations in postmenopausal women. However, short-term changes in diet may have significant and beneficial effects on blood insulin and leptin concentrations.

Diet and colorectal cancer mortality: results from the Japan Collaborative Cohort Study

The relationship between diet and colorectal cancer mortality was analyzed in a prospective study of 45,181 men and 62,643 women aged 40-79 yr enrolled in the Japan Collaborative Cohort Study. Between 1988 and 1990, subjects completed a self-administered questionnaire on their sociodemographic characteristics, diet, and other lifestyle habits. During the follow-up period (average 9.9 yr), 284 colon cancer deaths (138 men and 146 women) and 173 rectal cancer deaths (116 men and 57 women) were confirmed. The only significant association of colorectal cancer mortality with vegetable intake was observed between male rectal cancer mortality and green leafy vegetable consumption [hazard ratio (HR) using Cox proportional hazard models = 0.6; 95% confidence interval (CI) = 0.3-0.9; P for trend = 0.02]. Yogurt intake was also inversely associated with male rectal cancer mortality (HR = 0.5; 95% CI = 0.2-1.0; P for trend = 0.04). Egg consumption was positively associated with male colon cancer mortality (P for trend = 0.04). Women with high fruit consumption had increased colon cancer mortality (HR = 1.6; 95% CI = 1.0-2.6; P for trend = 0.04). It should be noted that this study lacked statistical power due to small sample size and measurement error in the food-frequency questionnaire. Further investigation is therefore necessary to confirm the association between diet and colorectal cancer, especially by subsites and gender.

Trends in childhood obesity in Japan over the last 25 years from the national nutrition survey

OBJECTIVE

To describe the 25-year changes in BMI (measured in kilograms per meters squared) and the prevalence of obesity in Japanese children with special reference to urban-rural differences.

RESEARCH METHODS AND PROCEDURES

We used the data sets from the cross-sectional annual nationwide surveys (National Nutrition Survey, Japan) conducted from 1976 to 2000 and comprising 29,052 boys and 27,552 girls between 6 and 14 years of age. We carried out the trend analyses with the data on sex and age groups and on residential areas according to the size of the municipality (metropolitan areas, cities, and small towns).

RESULTS

The mean (age-adjusted) BMI increased by +0.32 kg/m(2) per 10 years in boys and by +0.24 kg/m(2) per 10 years in girls, increases that were remarkable in small towns. The prevalence of obese boys and girls increased from 6.1% and 7.1%, respectively, in the time-period 1976 to 1980, to 11.1% and 10.2% in 1996 to 2000. The increasing trend was most evident in 9- to 11-year-old children of both sexes living in small towns, whereas no changes were observed in girls in metropolitan areas.

DISCUSSION

Our data clearly show increasing trends in obesity prevalence in Japanese school children. Degrees of the increasing trends, however, differed across sex and age groups and residential areas, demonstrating a particular phenomenon that girls in metropolitan areas were unlikely to become obese. These epidemiological aspects indicate the priorities for intervention in population strategies to control obesity in children.

The development of diabetes mellitus in Wistar rats kept on a high-fat/low-carbohydrate diet for long periods

The present study was performed to determine the effect of long-term feeding with a high-fat/low-carbohydrate (HF/LC) diet on the onset of type-2 diabetes mellitus in normal rats. Male Wistar Imamichi rats were kept on a Control (carbohydrate 60%, fat 15%) or HF/ LC (carbohydrate 10%, fat 65%) diet for 16 mo. An intraperitoneal glucose tolerance test was performed once every 2 mo. Glucose tolerance was impaired 2 mo after the start of HF/LC diet feeding, accompanied by a decrease in the insulinogenic index. Along with time of HF/LC diet feeding, the glucose tolerance was further deteriorated with more serious impairment of insulin secretion and sensitivity. At the end of the experiment, 15 of 18 rats in the HF/LC group were diabetic, whereas only 4 of 17 rats in the Control group were diabetic. The present results demonstrate that longterm feeding with a HF/LC diet decreases the secretion and sensitivity of insulin, and induces diabetes mellitus in rats. Furthermore, long-term feeding with such a diet may produce adverse effects on the blood plasma lipid profile, with elevated levels of triglycerides, nonesterified fatty acids, total cholesterol, and reduced levels of high density protein cholesterol in the plasma.

Long-term effects of high dietary fiber intake on glucose tolerance and lipid metabolism in GK rats: comparison among barley, rice, and cornstarch

Whether the intake of high dietary fiber may improve glycemic control in individuals with type 2 diabetes has been controversial. This study was conducted to observe the long-term effects of dietary fiber intake on glucose tolerance and lipid metabolism in rats. Thirty male type 2 diabetic model GK rats were divided randomly into 3 groups. Each group was fed either a barley (high-dietary fiber) diet, rice (low-dietary fiber) diet, or cornstarch (very-low-dietary fiber) diet. The rats were pair-fed for 9 months. The intake of the barley diet significantly improved the area under the plasma glucose concentration time curves, lowered the fasting plasma glucose and glycosylated hemoglobin levels, and decreased plasma total cholesterol (T Chol), triglycerides (TG), and free fatty acid (FFA) levels. This study demonstrated that long-term intake of barley has beneficial effects on glucose tolerance and lipid metabolism and suggests the intake of unrefined cereal foods should increase as a diet therapy for type 2 diabetes.