Dietary intake and serum total cholesterol level: their relationship to different lifestyles in several Japanese populations

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.

History of cardiovascular epidemiology in Japan

There are several patterns of epidemiological study in Japan. One is the international collaborative studies, such as Seven Countries Study, NI-HON-SAN Study, International Study of Salt and Blood Pressure (INTERSALT), International Study of Macro-and Micro-nutrients and Blood Pressure (INTERMAP), and Monitoring of Cardiovascular Disease (MONICA). The next one is the several cohort studies in Japanese unique surveys, such as Hisayama Study, Osaka-Akita Study, Tanno-Sobetsu Study, Suita Study, Ohazama Study, National Integrated Project for Prospective Observation of Noncommunicable Disease and Its Trends in the Aged (NIPPON DATA), Japan Collaborative Cohort (JACC), and Japan Public Health Center-Based Study (JPHC). Finally, some recent special meta-analysis in Japan are Japan Arteriosclerosis Longitudinal Study (JALS) and Evidence for Cardio-vascular Prevention from Observational Cohorts in Japan (EPOCH-JAPAN). The aim of this review is to introduce the history of epidemiologcal study, especially, cardiovascular epidemiology from the mid-20th century to in the early 21st century by dividing three patterns.

A Scoping Review of Epidemiological Studies on Intake of Sugars in Geographically Dispersed Asian Countries: Comparison of Dietary Assessment Methodology

Previous systematic reviews, which focused on sugar intake and its relation with health issues, were mainly conducted in Western countries, not Asian countries characterized by differences in dietary habits and disease prevalence. The scarcity of Asian studies may be attributed to the lack of assessment tools for estimating sugar intake. To provide an overview of the epidemiological studies on sugar intake in Asian countries, with a primary focus on dietary assessment methodology for estimating sugar intake, we conducted a scoping review of the epidemiological studies estimating sugar intake in Asian countries (the United Nations' definition) and Taiwan using PubMed and Web of Science. Study quality was evaluated based on its assessment of sugar intake in the whole diet, dietary assessment methods, and data sources used for estimating sugar content. We identified 143 studies from 136 publications from Eastern (n = 63), Southern (n = 30), South-Eastern (n = 26), and Western (n = 24) Asia. Total sugars were investigated in 95 studies, while 23-30 studies investigated sucrose, fructose, added sugars, and free sugars. The main aim of the selected studies was assessment of diet-disease relations (n = 85) and estimation of dietary intake (n = 40), and 62 studies assessed sugars as the primary exposure/outcome. A total of 120 studies assessed sugar intake in the whole diet, and 62 studies used validated FFQs or multiple-day dietary assessment methods. Only 41 studies used country-specific comprehensive food-composition databases or directly measured sugar content. Only 17 studies reported high-quality data. This review elucidated a sufficient number of epidemiological studies estimating sugar intake across Asian countries; however, most studies reported low-quality data. The results from our review showed that both feasible and validated dietary assessment methods, as well as comprehensive country-specific sugar-composition databases, are essential for producing high-quality studies with accurate sugar intake to examine its association with health outcomes.

Tracking Pattern of Total Cholesterol Levels from Childhood to Adolescence in Japan

Aims: This study aimed to evaluate the tracking pattern of serum total cholesterol (TC) levels among Japanese children using data collected continuously for 9 years and examine the relationship between childhood and adulthood TC levels.

Methods: TC levels of 2,608 first grade primary school children enrolled during 1981-2014 from two Japanese towns were measured during annual health check-ups. Nine-year trajectories of estimated TC levels stratified by TC quartiles in the first grade were analyzed using a mixed effects model. Adulthood TC levels were measured in participants who underwent health check-ups in the same area.

Results: Overall, 1,322 boys and 1,286 girls in the first grade of a primary school were followed for 9 years. Trajectories of TC levels during the period stratified by TC quartiles in the first grade differed significantly and did not cross each other for both sexes. Childhood data of 242 adult participants were linked with their adulthood data; the mean of age was late 20s for both sexes. The average TC levels in adulthood increased from the first to the fourth quartile in the first grade. Additionally, trajectories of TC levels differed between boys and girls. The later the admission year, the more elevated the TC levels in girls.

Conclusion: Among Japanese children, TC levels were strongly tracked from childhood to adolescence for 9 years, and elevated TC levels in childhood were related to elevated TC levels in adulthood. Maintaining appropriate TC levels during childhood may be important to prevent future coronary artery diseases.

Mortality-and Health-Related Factors in a Community-Dwelling of Oldest-Older Adults at the Age of 90: A 10-Year Follow-Up Study

Mortality is obviously intended for epidemiological studies of community-dwelling older adults. There are several health-related factors associated with nutritional status and mortality. The aim of this study was to elucidate the risk factor for mortality in community-dwelling oldest-older adults at the age of 90 and clarify the structure of health-related factors associated with mortality. A 10-year follow-up study was performed for 93 subjects at the age of 90. The mean and median of their survival days were 2373 and 2581 days for women, and 1694 and 1793 days for men. By Cox's proportional hazards model, health-related factors associated with mortality were self-assessed for chewing ability, activities of daily living (ADLs), serum albumin, total cholesterol, serum creatinine, and gripping power for women but not for men. These factors interacted with each other, and the association of these factors was different in women and men. Self-assessed chewing ability was a powerful risk factor for mortality in women at the age of 90. It acted independently from nutritional status. For older adults, addressing healthy food choices together with improved oral functions is useful. However, risk factors for mortality may depend on the life stage of subjects. To investigate the risk factor for the mortality, the life course approach is necessary.

The Relationship of Dietary Cholesterol with Serum Low-Density Lipoprotein Cholesterol and Confounding by Reverse Causality: The INTERLIPID Study

Aim: The positive relationship between dietary cholesterol and serum cholesterol has been questioned by a set of recent cohort studies. This study aimed to investigate how employment status and education years relate to the association between dietary cholesterol and serum low-density lipoprotein cholesterol (LDL-C) in a Japanese population.

Methods: A population-based, random sample, cross-sectional study (INTERLIPID) was performed. Among 1,145 Japanese individuals aged 40–59 years, 106 were excluded because of special diets, use of lipid-lowering drugs, hormone replacement, and missing data, leaving 1,039 individuals (533 men and 506 women). Dietary cholesterol was assessed from four 24-h dietary recalls, and LDL-C was measured enzymatically with an autoanalyzer. A standard questionnaire inquired about employment status and education years.

Results: In men, a 1 standard deviation (SD) higher dietary cholesterol was associated with 3.16 mg/dL lower serum LDL-C (P = 0.009; unadjusted model). After adjustment for covariates, higher serum LDL-C was estimated per 1 SD higher intake of dietary cholesterol in nonemployed men [self-employed, homemakers, farmers, fishermen, and retired employees; β = +9.08, 95% confidence interval (CI) = +0.90–+17.27] and less educated men (β = +4.46, 95% CI = −0.97–+9.90), whereas an inverse association was observed in employed men (β = −3.02, 95% CI= −5.49–−0.54) and more educated men (β = −3.66, 95% CI = −6.25–−1.07).

Conclusions: In men who were nonemployed and less educated, a higher intake of dietary cholesterol was associated with elevated concentrations of serum LDL-C, whereas an inverse association was observed in men who were employed and more educated.

Time-Related Changes in Relationships Between the Keys Score, Dietary Lipids, and Serum Total Cholesterol in Japan - NIPPON DATA80/90/2010

BACKGROUND

In recent years, individuals with high serum total cholesterol (TC) have been more likely to modify their diet by reducing their intake of dietary lipids. The aim of this study was to investigate time-related changes in the relationships between the Keys score, dietary lipids, and TC between 1980 and 2010 in representative Japanese populations. Methods and Results: We used 3 cross-sectional cohort studies conducted among Japanese representative populations in 1980, 1990, and 2010 (NIPPON DATA80/90/2010) for the analyses. We analyzed data for 10,365, 7,714, and 2,657 participants, respectively, in each dataset. The relationships between TC and the Keys score (calculated by dietary lipids, cholesterol, and energy intake)/dietary lipids were examined. In men, a 1-unit higher Keys score correlated with 0.92 mg/dL and 0.64 mg/dL TC in 1980 and 1990, respectively, but not in 2010. In women, a 1-unit higher Keys score correlated with 0.70 mg/dL and 0.74 mg/dL TC in 1980 and 1990, respectively, but with 0.33 mg/dL in 2010. In men and women, dietary cholesterol, saturated fatty acid (SFA), and trans fatty acid (TFA) levels were positively associated with TC concentrations in 1980 and 1990, but not in 2010.

CONCLUSIONS

In these representative Japanese populations, a higher Keys score as well as dietary cholesterol, SFA, and TFA levels correlated with higher TC concentrations in 1980/1990, but the relationships were weaker or not observed in 2010.

Twenty-four-Hour Urinary Potassium Excretion, But Not Sodium Excretion, Is Associated With All-Cause Mortality in a General Population

Background

Few studies have examined the relationship between accurate monitoring of sodium or potassium consumption and mortality. We aimed to investigate the association between 24‐hour urinary sodium or potassium excretion and ≈30‐year mortality in a Japanese population using 24‐hour urine collection.

Methods and Results

We enrolled a total of 1291 participants, aged 21 to 85 years, who underwent health checkups, including a blood test and 24‐hour urine collection. They were followed up for 27.5±9.9 years by December 31, 2015, and the final follow‐up rate was 95.8%. Cox proportional hazards regression analysis was used to assess the association between 24‐hour urinary sodium or potassium excretion and all‐cause mortality. At baseline, the mean 24‐hour urinary sodium and potassium excretions were 5.80±2.28 g/d and 1.85±0.82 g/d, respectively. There were 631 deaths during the follow‐up. The cumulative survival rate was significantly decreased in the lowest quartile compared with the other higher groups. In the Cox proportional hazard model after adjustment for age and sex, 24‐hour urinary potassium excretion, but not sodium excretion, was inversely associated with all‐cause mortality. We divided the 24‐hour urinary potassium excretion levels into quartiles. After adjustment for confounding factors, the hazard ratio of all‐cause mortality in the highest quartile of 24‐hour urinary potassium excretion versus the lowest was 0.62 (95% confidence interval, 0.48–0.79; P<0.001).

Conclusions

The 24‐hour urinary potassium excretion, but not sodium excretion, was significantly associated with all‐cause mortality in the general population.

Traditional Risk Factors for Stroke in East Asia

Stroke is one of the leading causes of death and morbidity worldwide. The occurrence of stroke is strongly dependent on well-known vascular risk factors. After rapid modernization, urbanization, and mechanization, East Asian countries have experienced growth in their aged populations, as well as changes in lifestyle and diet. This phenomenon has increased the prevalence of vascular risk factors among Asian populations, which are susceptible to developing cardiovascular risk factors. However, differing patterns of stroke risk factor profiles have been noted in East Asian countries over the past decades. Even though the prevalence of vascular risk factors has changed, hypertension is still prevalent and the burden of diabetes and hypercholesterolemia will continue to increase. Asia remains a high tobacco-consuming area. Although indicators of awareness and management of vascular risk factors have increased in many East Asian countries, their rates still remain low. Here we review the burdens of traditional risk factors, such as hypertension, diabetes, hypercholesterolemia, and smoking in East Asia. We will also discuss the different associations between these vascular risk factors and stroke in Asian and non-Asian populations.

Dietary sodium-to-potassium ratio as a risk factor for stroke, cardiovascular disease and all-cause mortality in Japan: the NIPPON DATA80 cohort study

OBJECTIVES

To evaluate the impact of dietary sodium and potassium (Na-K) ratio on mortality from total and subtypes of stroke, cardiovascular disease (CVD) and all causes, using 24-year follow-up data of a representative sample of the Japanese population.

SETTING

Prospective cohort study.

PARTICIPANTS

In the 1980 National Cardiovascular Survey, participants were followed for 24 years (NIPPON DATA80, National Integrated Project for Prospective Observation of Non-communicable Disease And its Trends in the Aged). Men and women aged 30-79 years without hypertensive treatment, history of stroke or acute myocardial infarction (n=8283) were divided into quintiles according to dietary Na-K ratio assessed by a 3-day weighing dietary record at baseline. Age-adjusted and multivariable-adjusted HRs were calculated using the Mantel-Haenszel method and Cox proportional hazards model.

PRIMARY OUTCOME MEASURES

Mortality from total and subtypes of stroke, CVD and all causes.

RESULTS

A total of 1938 deaths from all causes were observed over 176 926 person-years. Na-K ratio was significantly and non-linearly related to mortality from all stroke (p=0.002), CVD (p=0.005) and total mortality (p=0.001). For stroke subtypes, mortality from haemorrhagic stroke was positively related to Na-K ratio (p=0.024). Similar relationships were observed for men and women. The observed relationships remained significant after adjustment for other risk factors. Quadratic non-linear multivariable-adjusted HRs (95% CI) in the highest quintile versus the lowest quintile of Na-K ratio were 1.42 (1.07 to 1.90) for ischaemic stroke, 1.57 (1.05 to 2.34) for haemorrhagic stroke, 1.43 (1.17 to 1.76) for all stroke, 1.39 (1.20 to 1.61) for CVD and 1.16 (1.06 to 1.27) for all-cause mortality.

CONCLUSIONS

Dietary Na-K ratio assessed by a 3-day weighing dietary record was a significant risk factor for mortality from haemorrhagic stroke, all stroke, CVD and all causes among a Japanese population.

Low-carbohydrate diets and cardiovascular and total mortality in Japanese: a 29-year follow-up of NIPPON DATA80

Long-term safety of consuming low-carbohydrate diets (LCD) in Asian populations, whose carbohydrate intake is relatively high, is not known. In the present study, the association of LCD with CVD and total mortality was assessed using data obtained in the NIPPON DATA80 (National Integrated Project for Prospective Observation of Non-communicable Disease and Its Trends in the Aged 1980) during 29 years of follow-up. At baseline in 1980, data were collected from study participants aged ≥ 30 years from randomly selected areas in Japan. LCD scores were calculated based on the percentage of energy as carbohydrate, fat and protein, estimated by 3 d weighed food records. A total of 9200 participants (56% women, mean age 51 years) were followed up. During the follow-up, 1171 CVD deaths (52% in women) and 3443 total deaths (48% in women) occurred. The multivariable-adjusted hazard ratio (HR) for CVD mortality using the Cox model comparing the highest v. lowest deciles of LCD score was 0·60 (95% CI 0·38, 0·94; P(trend) = 0·021) for women and 0·78 (95% CI 0·58, 1·05; P(trend) = 0·079) for women and men combined; the HR for total mortality was 0·74 (95% CI 0·57, 0·95; P(trend) = 0·029) for women and 0·87 (95% CI 0·74, 1·02; P(trend) = 0·090) for women and men combined. None of the associations was statistically significant in men. No differential effects of animal-based and plant-fish-based LCD were observed. In conclusions, moderate diets lower in carbohydrate and higher in protein and fat are significantly inversely associated with CVD and total mortality in women.

Unavailability of liver triacylglycerol increases serum cholesterol concentration induced by dietary cholesterol in exogenously hypercholesterolemic (ExHC) rats

BACKGROUND

Exogenously hypercholesterolemic (ExHC) rats develop hypercholesterolemia and low hepatic triacylglycerol (TAG) levels when dietary cholesterol is loaded. The responsible gene Smek2 was identified via linkage analysis using the original strain Sprague-Dawley (SD) rats. In this study, we compared SD and ExHC rats to investigate a relationship between hypercholesterolemia and the low hepatic TAG levels observed in ExHC rats.

METHODS

Male 4-weeks-old ExHC and SD rats were fed a 1% cholesterol diet for 1 week. Serum and liver parameters were analyzed. Gene expression and enzyme activities related to TAG metabolism were also assessed.

RESULTS

We reproducibly observed higher serum cholesterol and lower hepatic TAG levels in ExHC rats than in SD rats. Golgi apparatus in the livers of ExHC rats secreted β-very-low-density lipoprotein (β-VLDL) that had higher cholesterol ester (CE) and lower TAG content than those in the β-VLDL secreted by SD rats. Gene expression related to fatty acid and TAG synthesis in ExHC rats was lower than that in SD rats. Enzymatic activities for fatty acid synthesis were also relatively lower in ExHC rats. Moreover, the fatty acid composition of hepatic and serum CE in ExHC rats showed that these CEs were not modified after secretion from the liver despite the similar activities of serum lecithin-cholesterol acyltransferase (LCAT) in ExHC rats to those in SD rats.

CONCLUSIONS

Low production of liver TAG and secretion of CE-rich, TAG-poor β-VLDL without modification by LCAT in the circulation contributed to hypercholesterolemia induced by dietary cholesterol in ExHC rats.

Prospective care of heart failure in Japan: lessons from CHART studies

There are approximately 23 million patients with heart failure (HF) worldwide. The prognosis of patients with HF is still poor and a prospective approach for preventing and treating HF is necessary. The number of HF patients in Japan has been increasing since 1950 mainly because of a rapidly aging population. Furthermore, westernized dietary pattern, reduced physical activity, and obesity have become prominent, particularly in younger Japanese men. There is an increasing trend of diabetes and dyslipidemia, and the prevalence of smoking and hypertension continues to remain high. One of the largest HF cohorts in Japan, the CHART Studies, showed that coronary artery disease (CAD) was the most frequent etiology of HF currently. Thus, prospective strategies including accurate risk stratification, effective prevention of disease progression through evidence-based treatments, optimally personalized treatment particularly in elderly individuals, and life-long control of CAD risk factors are required to manage HF in Japan.

A Japanese health success story: trends in cardiovascular diseases, their risk factors, and the contribution of public health and personalized approaches

There has been a substantial decline in mortality from stroke and ischemic heart disease (IHD) in Japan between the 1960s and 2000s, which contributed to placing Japanese at the top of world’s life expectancy rankings. That mortality decline was attributable to reductions of blood pressure and smoking, in spite of increases in dyslipidemia and diabetes mellitus. The combination of public health and personalized treatment activities to enhance sodium reduction, balanced diets, smoking prevention/cessation as well as hypertension detection and treatment have contributed to the reduction of cardiovascular diseases, demonstrated by a community-based stroke prevention program. The health success story, however, contains an underlying concern about future health threats, the plateaued IHD mortality decline and increased IHD incidence among urban middle-aged men, probably due to increased dyslipidemia and diabetes. The IHD incidence and mortality trends need to be monitored because of a potential future problem for predictive, preventive and personalized medicine.

Relationship of the polyunsaturated to saturated fatty acid ratio to cardiovascular risk factors and metabolic syndrome in Japanese: the INTERLIPID study

AIM

There have been few studies on the relationships of the dietary polyunsaturated to saturated fatty acid ratio (P/S) to cardiovascular risk factors and metabolic syndrome. We hypothesized that there would be favorable relationships.

METHODS

Metabolic cardiovascular risk factors from dietary nutrient intake were investigated in 1,004 men and women aged 40-59 years from 4 population samples of Japanese. Multiple linear regression analysis was used to examine the relationship of the dietary P/S ratio to the following risk factors: hemoglobin A1c, blood pressure, serum triglycerides, LDL and total cholesterol, and HDL-cholesterol. Adjusted odds ratio of having metabolic syndrome was also calculated.

RESULTS

The dietary P/S ratio was significantly and inversely related to serum total and LDL cholesterol with control for possible confounding variables. We did not find any significant relationship between the P/S ratio and single metabolic risk factors or the prevalence of metabolic syndrome.

CONCLUSIONS

Managing the P/S ratio is important to control serum LDL-cholesterol; however, increasing the P/S ratio may not improve metabolic risk factors. Other countermeasures, such as weight control, greater physical activity, and smoking cessation should be recommended to prevent and control metabolic syndrome.

A Japanese diet and 19-year mortality: national integrated project for prospective observation of non-communicable diseases and its trends in the aged, 1980

Few studies have examined the association between Japanese diet and mortality outcomes. We analysed the relationship between a healthy Japanese diet and all-cause and cause-specific mortality using the database from the National Integrated Project for Prospective Observation of Non-Communicable Diseases and its Trends in the Aged, 1980. At baseline in 1980, data were collected on study participants aged > or =30 years from randomly selected areas in Japan. We defined a measure of a healthy reduced-salt Japanese diet based on seven components from FFQ. The total score ranged from 0 to 7, with 0 being least healthy and 7 being most healthy. Participants were divided into approximate tertiles of dietary scores (0-2, 3 and 4-7 scores). After excluding participants with co-morbidities, we followed 9086 participants (44 % men) for 19 years. There were 1823 all-cause and 654 cardiovascular deaths during the follow-up. With the dietary score group 0-2 serving as a reference, the Cox multivariate-adjusted hazard ratios for groups with scores 3 and 4-7 were 0.92 (95 % CI 0.83, 1.04) and 0.78 (95 % CI 0.70, 0.88) for all-cause mortality (trend P < 0.0001), and 0.91 (95 % CI 0.75, 1.10) and 0.80 (95 % CI 0.66, 0.97) for cardiovascular mortality (trend P = 0.022). Adherence to a healthy reduced-salt Japanese diet was associated with an approximate 20 % lower rate of all-cause and cardiovascular mortality.

Explanation for the Japanese paradox: prevention of increase in coronary heart disease and reduction in stroke

Japan's age-adjusted rate for mortality from stroke increased after the Second World War until 1965 and then showed a significant decline until 1990; however, the age-adjusted rate for mortality from all heart disease and coronary heart disease (CHD) increased until 1970 and then declined slowly. A puzzling question is why the rate of mortality from CHD declined in spite of an increase in serum total cholesterol level following an increase in fat consumption. It was confirmed that CHD incidence was far lower in several Japanese populations compared to Western countries in the " Monitoring Trends and Determinants in Cardiovascular Disease " (MONICA) project; therefore, the lower CHD mortality in Japan stems from the lower CHD incidence. CHD risk factors based on epidemiologic cohort studies in Japan were no different from those of other industrialized countries: hypertension, hypercholesterolemia, smoking and diabetes mellitus (DM). So, how can we explain this phenomenon?There are three possible explanations. One is the decline in population blood pressure level and the prevalence of hypertension during the years 1965-1990; the second is the decline in smoking rate in men and women; the third is that the serum total cholesterol level for middle-aged and elderly populations remains 5-15 mg/dL lower than that of the US elderly counterpart, although men aged 40-49 in Japan and the US had similar serum total cholesterol levels. It was also noted that elderly people in Japan, as observed in the Seven Countries Study, had far lower serum total cholesterol levels in midlife, i.e., around 160 mg/dL in the 1960s. This was not the case for elderly in the US where a higher serum total cholesterol level was observed in midlife. In conclusion, the lower serum cholesterol level in the past of Japanese middle-aged and elderly people compared to Western counterparts helps to maintain the low CHD incidence and mortality supported by the declining trend in blood pressure level and smoking rate for both men and women.

Medical costs of obese Japanese: a 10-year follow-up study of National Health Insurance in Shiga, Japan

BACKGROUND

For the Japanese population, a body mass index (BMI) of 25.0-29.9 is classified as obesity and is a risk factor for cardiovascular disorders such as hypertension.

METHODS

A cohort study to clarify obesity costs for a Japanese population was conducted utilizing baseline BMI and medical costs over a 10-year follow-up period. The participants were 4502 community dwelling Japanese National Health Insurance (NHI) beneficiaries aged 40-69 years. According to their baseline BMI values (kg/m(2)), participants were classified into the following three categories: BMI < 18.5, 18.5 < or = BMI < 25.0 and 25.0 < or = BMI. Medical costs per person per month were compared among the three categories. Excess medical costs attributable to the 25.0 < or = BMI category compared to the 18.5 < or = BMI < 25.0 category were estimated.

RESULTS

Approximately 20% of the Japanese population studied had a BMI of 25.0 or over. A J-shaped relationship between BMI and personal total medical costs was observed. Personal total medical costs per month determined from the 10-year follow-up in each category were 189 Euros (BMI < 18.5), 134 Euros (18.5 < or = BMI < 25.0) and 155 Euros (25.0 < or = BMI). A J-shaped pattern was observed after adjusting for age, sex, smoking and drinking habits, and excluding early deceased participants. Furthermore, smoking habit did not modify the J-shaped pattern of total medical costs. The estimated excess medical costs for the 25.0 < or = BMI category represented 3.1% of the total medical costs for the entire study population (634 105 Euros).

CONCLUSION

The Japanese NHI beneficiaries with a BMI of 25.0 or over showed increased medical costs compared to those with a BMI of 18.5-24.9.

Egg consumption, serum total cholesterol concentrations and coronary heart disease incidence: Japan Public Health Center-based prospective study

Limited egg consumption is often recommended to reduce serum cholesterol concentration for the prevention of CHD. We examined the association of egg consumption and total cholesterol concentration with the risk of CHD. A total of 90 735 subjects (19 856 men and 21 408 women, aged 40-59 years in cohort I; 23 463 men and 26 008 women, aged 40-69 years in cohort II) were followed from 1990-4 to the end of 2001 under the Japan Public Health Center-based prospective study. Total cholesterol was obtained in 36 % of the subjects. Men and women were combined for the analyses. The subjects were categorised into four groups according to egg consumption. Subjects with total cholesterol >or=2200 mg/l were less frequent in frequent egg consumption groups in both cohorts (trend P<0.0001). Subjects with <1 d/week of egg consumption were more likely to avoid a cholesterol-rich diet. Egg consumption was not associated with the risk of CHD, although total cholesterol was significantly related to the risk of CHD. The multivariate hazard ratio of CHD in subjects with total cholesterol >or=2400 v. <1800 mg/l was 2.17 (95 % CI 1.22, 3.85; trend P=0.0018). In conclusion, eating eggs more frequently, up to almost daily, was not associated with an increase in CHD incidence for middle-aged Japanese men and women. Subjects with hypercholesterolaemia were less frequently in frequent egg consumption groups, probably because they avoided eating eggs.

[Changes in dietary intake among Japanese-Brazilians in Bauru, São Paulo, Brazil, 1993-2000]

Cross-sectional surveys were performed in 1993 and 2000 on Japanese-Brazilians (n = 328) of both sexes, aged 40 to 79 years in 1993, living in Bauru, São Paulo State. Both surveys examined food intake using food frequency questionnaires. Dietary intake in both surveys was compared to Wilcoxon tests according to gender (p < 0.05). Calories from dietary fat increased by 16% in both genders (mean values in 2000: 31.5% for women and 30.8% for men). When the surveys were compared, the main dietary changes were: (a) a 40% increase in oleic and linoleic acids and calories from fat and (b) a 20% reduction in dietary cholesterol in both sexes. Among women, an increase in total calorie intake with reduced consumption of vegetables and calories from sweets were observed. Despite increased intake of total dietary fat, there was a decrease in cholesterol intake and an increase in oleic and linoleic acids, fruit, and calcium. However, calcium and vegetable consumption is still short of international recommendations.

Association between fish consumption and all-cause and cause-specific mortality in Japan: NIPPON DATA80, 1980-99

PURPOSE

Although high consumption of fish may be one of the contributing factors for Japanese longevity, no epidemiological study using Japanese data has tested this hypothesis.

SUBJECTS AND METHODS

The relationship between fish consumption and all-cause as well as cause-specific mortality was analyzed using the database of NIPPON DATA80. At baseline in 1980, history, physical, and blood biochemical measurement and a nutritional survey by the food-frequency method were performed in randomly selected community-based subjects aged 30 years and over in Japan. After exclusion of subjects with significant comorbidities at baseline, we followed 3945 men and 4934 women for 19 years. Men and women were analyzed comprehensively. Age- and sex-adjusted and multivariate adjusted relative risk for all-cause or cause-specific mortality was calculated using a Cox proportional hazards model with delayed entry.

RESULTS

During 19 years of followup, there were 1745 deaths. Subjects were divided into 5 groups according to fish consumption frequency. The multivariate Cox analyses showed that relative risks for subjects who ate fish more than twice daily compared with those of subjects who ate 1 to 2 times weekly were 0.99 (95% confidence intervals: 0.77-1.27) for all-cause, 1.26 (0.70-2.29) for stroke, 0.92 (0.20-4.23) for cerebral hemorrhage, 1.09 (0.48-2.43) for cerebral infarction, and 0.91 (0.35-2.35) for coronary heart disease mortality.

CONCLUSION

Our results did not provide evidence in support of the fish hypothesis, perhaps because the majority of the Japanese subjects in the study ate fish more than the threshold level shown to be beneficial in the previous studies.

Frequency of Food Intake and Estimated Nutrient Intake among Men and Women: The JACC Study

BACKGROUND: The aim of this study was to determine the frequency of food intake and estimated nutrient intake in the JACC study cohort.

METHODS: The subjects were 46,465 men and 64,327 women aged 40-79 years who responded to the self-administered food frequency questionnaire. We calculated the dietary intake of major nutrients by multiplying the frequency of consumption of each food with each portion size, estimated from a validation study.

RESULTS: Women reported to more likely consume vegetables, seaweed, fruits, sweets, oolong-tea, western-style-breakfast, and less likely to consume rice and miso-soup than men. Women reported less preference of salty foods and fatty foods than men. Compared with men, women had higher mean intakes of carotene and vitamin C, and lower intake of total energy, carbohydrate and sodium. The frequency of consumption of beef, chicken, dairy products, fresh fish, fish products, rice, and miso-soup increased with age in men, and that of vegetables, seaweed, beans, tofu, fruits, sweets, and green-tea increased with age in both sexes. Men aged 40-49years had the lowest mean intake levels of crude fiber, calcium, iron, retinol, carotene, and vitamins A, C, and E. Women aged 40-49years had the lowest mean intake levels of crude fiber, iron, and vitamins C. Women aged 70-79years had the lowest mean intake levels of calcium, retinol, and vitamins A.

CONCLUSIONS: Women had a more westernized dietary pattern than men. Elderly men had a mixture of unhealthy and healthy dietary patterns while elderly women generally had a healthier dietary pattern compared with younger persons.

Egg consumption, serum cholesterol, and cause-specific and all-cause mortality: the National Integrated Project for Prospective Observation of Non-communicable Disease and Its Trends in the Aged, 1980 (NIPPON DATA80)

BACKGROUND

Because egg yolk has a high cholesterol concentration, limited egg consumption is often suggested to help prevent ischemic heart disease (IHD).

OBJECTIVE

We epidemiologically examined the validity of this recommendation.

DESIGN

We analyzed the relations of egg consumption to serum cholesterol and cause-specific and all-cause mortality by using the NIPPON DATA80 (National Integrated Project for Prospective Observation of Non-communicable Disease And its Trends in the Aged, 1980) database. At the baseline examination in 1980, a nutritional survey was performed by using the food-frequency method in Japanese subjects aged > or =30 y. We followed 5186 women and 4077 men for 14 y.

RESULTS

The subjects were categorized into 5 egg consumption groups on the basis of their responses to a questionnaire (> or =2/d, 1/d, 1/2 d, 1-2/wk, and seldom). There were 69, 1396, 1667, 1742, and 315 women in each of the 5 groups, respectively. Age-adjusted total cholesterol (5.21, 5.04, 4.95, 4.91, and 4.92 mmol/L in the 5 egg consumption categories, respectively) was related to egg consumption (P < 0.0001, analysis of covariance). In women, unadjusted IHD mortality and all-cause mortality differed significantly between the groups [IHD mortality: 1.1, 0.5, 0.4, 0.5, and 2.0 per 1000 person-years, respectively (P = 0.008, chi-square test); all-cause mortality: 14.8, 8.0, 7.5, 7.5, and 14.5 per 1000 person-years, respectively (P < 0.0001, chi-square test)]. In men, egg consumption was not related to age-adjusted total cholesterol. Cox analysis found that, in women, all-cause mortality in the 1-2-eggs/wk group was significantly lower than that in the 1-egg/d group, whereas no such relations were noted in men.

CONCLUSION

Limiting egg consumption may have some health benefits, at least in women in geographic areas where egg consumption makes a relatively large contribution to total dietary cholesterol intake.

Intake of animal products and stroke mortality in the Hiroshima/Nagasaki Life Span Study

BACKGROUND

To determine whether intake of animal products was associated with a reduced risk of stroke mortality in a large-scale population-based cohort in Japan.

METHODS

A self-administered questionnaire, including questions on dietary habits, was mailed to the members of the Life Span Study, a cohort of people exposed and non-exposed to atomic bomb radiation, who were alive as of 1 September 1979. Animal products included frequency intake of beef/pork, chicken, ham/sausage, milk, dairy products, eggs, fish, and broiled fish. Responses were obtained from 40 349 people (72%): 15 350 men (mean age 54 years) and 24 999 women (mean age 58 years). The subjects were followed for 16 years, and deaths were ascertained by linkage to the nationwide family registration system of Japan. The associations between diet and stroke mortality were examined using a Cox proportional hazard model.

RESULTS

During the follow-up period, 1462 stroke deaths occurred. Four animal products comprising eggs, dairy products, fish, and broiled fish were independently associated with a decreased risk of stroke mortality; while beef/pork, chicken, ham/ sausage, and milk consumption were not associated with stroke death. A composite measure of eggs, dairy products, fish, and broiled fish intake was calculated, and the highest tertile was significantly inversely associated with total stroke mortality (Hazards Ratio [HR] = 0.80, 95% CI: 0.68, 0.93) compared with the lowest tertile. The protective effect of animal product intake on total stroke death was largely confined to intracerebral haemorrhage death; the RH of intracerebral haemorrhage death for the highest tertile of consumption was 0.72 (95% CI: 0.53-0.98) compared with the lowest tertile; animal products intake was not related to cerebral infarction mortality (HR = 0.84; 95% CI: 0.67-1.06).

CONCLUSIONS

Intake of animal products such as eggs, dairy products, and fish may be protective against intracerebral haemorrhage, but is not related to cerebral infarction mortality.

Coronary heart disease mortality among men aged 35-44 years by prefecture in Japan in 1995-1999 compared with that among white men aged 35-44 by state in the United States in 1995-1998: vital statistics data in recent birth cohort

The levels of risk factors for coronary heart disease (CHD) in men in the post World War II (WWII) birth cohort are almost similar between Japan and the USA, except for the considerably higher prevalence of cigarette smoking in Japan and the much higher prevalence of obesity in the USA. The present study evaluated the CHD mortality among men in the post WWII birth cohort by prefecture in Japan in 1995-1999 and then compared the data with those for white men in different states in the USA. There was a greater than 2-fold difference in CHD mortality among men aged 35-44 by prefecture in Japan: 5.3/100,000 in Kumamoto vs 12.6/100,000 in Tochigi. CHD mortality among men aged 35-44 in the top 3 prefectures in Japan is about half that of white men in the USA and is similar to that of white men in the lowest 3 states. The much lower CHD mortality in Japan does not appear to be caused by differences in the classification of causes of death and the results suggest that there may be strong and important protective factors that reduce the risk of CHD in Japan.

A comparison of coronary arteries from Japanese and NZ subjects

This paper describes a comparison of the anterior descending branch of the left coronary artery from 198 Japanese subjects of ages less than 60 yrs, with 301 New Zealand individuals of similar ages. The object of the study was to determine whether there were structural differences present which could be partially responsible for the low incidence of atherosclerosis in Japanese as well as the known low blood lipid levels. It was found that the internal elastic lamina of Japanese coronary arteries was less well formed at birth than that of NZ subjects. Intimal thickening was greater in Japanese coronary arteries from birth to the end of the first decade, but increased less rapidly with age, and was only about half as great as that of NZ vessels in the older age groups. The thickened intima of Japanese arteries was more uniform round the circumference of the vessel, the luminal surface was better formed with more stainable elastin present subjacent to the endothelial cells, and there was less evidence of mural thrombosis. NZ arteries showed pronounced eccentricity of the intima, more extensive lipid deposits, a poorly defined luminal surface, and frequent evidence of mural thrombosis.

Different trends in serum cholesterol levels among rural and urban populations aged 40-59 in Japan from 1960 to 1990

In Japan, coronary heart disease mortality is low and has been declining since 1970, despite recent increases in serum cholesterol levels which have been reported in nationwide surveys. Longitudinal and cross-sectional surveys of serum cholesterol levels in rural and urban populations from 1960 to 1990 were reviewed. In the surveys in the 1960s, serum cholesterol levels in urban populations were higher than those in rural populations. An increase in serum cholesterol levels for men and women was observed in all longitudinal studies among rural populations; mean increases in serum cholesterol levels per year were 0.034 mmol/l (p < 0.001) and 0.033 mmol/l (p < 0.001), respectively. These trends were still observed after combining the data from the longitudinal and cross-sectional studies in both men and women (0.027 and 0.028 mmol/l per year, respectively), while there was no significant increase among urban populations. The results of National Nutrition Surveys are consistent with these findings and show that meat consumption per day per capita increased from 23.9 to 66.2 g in rural populations and 51.2 to 77.6 g in urban populations in the 1966 and 1990 surveys. It is suggested that different trends in coronary heart disease mortality should also be apparent in rural and urban populations over this period.

Nutrition and the global risk for chronic diseases: the INTERHEALTH nutrition initiative. The INTERHEALTH Steering Committee

As chronic, noncommunicable diseases (NCDs) have emerged as leading causes of morbidity and mortality worldwide, the World Health Organization's INTERHEALTH Programme, an international collaboration currently involving 15 countries, has focused its attention on population-based NCD prevention. Participating nations include Australia, Chile, China, Cuba, Cyprus, Finland, Japan, Lithuania, Malta, Mauritius, Russia, Sri Lanka, Tanzania, Thailand, and the United States. This paper will review and assess global trends in food and nutrient intake among INTERHEALTH countries between 1954 and 1986.

Green tea consumption and serum lipid profiles: a cross-sectional study in northern Kyushu, Japan

METHODS. The relation between green tea consumption and serum lipid concentrations was examined using cross-sectional data on 1,306 males who received the retirement health examination at the Self-Defense Forces Fukuoka Hospital between October 1986 and December 1988. RESULTS. After adjustment for rank, smoking, alcohol use, physical activity, and body mass index, serum total cholesterol levels were found to be inversely related to the consumption of green tea while no association was noted with serum triglycerides and high-density lipoprotein cholesterol. Adjusted mean concentrations of total cholesterol were 8 mg/dl lower in men drinking nine cups or more per day than in those consuming zero to two cups per day. Serum cholesterol levels were inversely associated with traditional Japanese dietary habits (intake of rice and soy bean paste soup) and positively associated with Westernized habits. Additional adjustment for these dietary variables did not alter the inverse relation between green tea and total cholesterol.

Feasibility of a randomized trial of a low-fat diet for the prevention of breast cancer: dietary compliance in the Women's Health Trial Vanguard Study

The Women's Health Trial Vanguard Study was conducted to examine the feasibility of a nationwide, randomized multicenter intervention trial to test the hypothesis that a low-fat diet followed for a period of 10 years will reduce breast cancer risk. Women ages 45-69 years at increased risk of breast cancer were randomized into intervention (low-fat diet, n = 184) and control (usual diet, n = 119) groups. On the basis of 4-day food records, baseline fat intakes were comparable in the two groups, averaging 1,718 kcal with 39% of energy as fat. Intervention women reported substantially lower fat intake at 6 (20.9% kcal), 12 (21.6%), and 24 months (22.6% kcal). In contrast, control women reported only slight reductions in fat intake (37.3% kcal at 12 months and 36.8% kcal at 24 months). Evidence that these women were indeed complying with the low-fat dietary intervention comes from (a) the reasonable nature of reported nutrient changes within food groups in the intervention women and (b) agreement between observed and expected differences in plasma total cholesterol between the control and the intervention groups. At 12 months, the observed control - intervention plasma cholesterol difference was 13.1 +/- 4.6 mg/dl while the expected difference based on the Keys equation was 15.1 +/- 1.1 mg/dl; at 24 months, the observed difference was 15.5 +/- 4.3 mg/dl and the expected difference was 12.0 +/- 1.2 mg/dl. These analyses indicate that the intervention women made substantial dietary changes and have successfully maintained these changes over a 2-year period. This study thus demonstrates the feasibility of a randomized trial with an intensive low-fat dietary intervention.

A low-fat diet decreases high density lipoprotein (HDL) cholesterol levels by decreasing HDL apolipoprotein transport rates

Diets that reduce atherosclerosis risk lower levels of HDL cholesterol (HDL-C), but the significance of this is unclear. To better understand the mechanism of this phenomenon we studied the turnover of HDL apolipoproteins A-I and A-II in 13 subjects on two contrasting metabolic diets. Upon changing from high to low intake of saturated fat and cholesterol the mean HDL-C decreased 29% from 56 +/- 13 (SD) to 40 +/- 10 mg/dl, while apo A-I levels fell 23% from 139 +/- 22 to 107 +/- 22 mg/dl (both P less than 0.001). Mean apo A-II levels did not change. The fractional catabolic rate (FCR) of apo A-I increased 11% from 0.228 +/- 0.048 to 0.254 +/- 0.063 pools/d, while its absolute transport rate (TR) decreased 14% from 12.0 +/- 2.7 to 10.3 +/- 3.4 mg/kg per d (both P = 0.005). The decrease in HDL-C and apo A-I levels correlated with the decrease in apo A-I TR (r = 0.79 and 0.83, respectively; P less than 0.001), but not with the increase in apo A-I FCR (r = -0.04 and -0.02, respectively). In contrast, within each diet the HDL-C and apo A-I levels were inversely correlated with apo A-I FCR both on the high-fat (r = -0.85 and -0.77, P less than 0.001 and = 0.002, respectively) and low-fat diets (r = -0.67 and -0.48, P = 0.012 and 0.098, respectively) but not with apo A-I TR. In summary, diet-induced changes in HDL-C levels correlate with and may result from changes in apo A-I TR. In contrast, differences in HDL-C levels between people on a given diet correlate with and may result from differences in apo A-I FCR. Therefore, the mechanism of dietary effects on HDL levels differs substantially from the mechanism explaining the differences in levels between individuals on a fixed diet. In assessing coronary heart disease risk, it may be inappropriate to conclude that diet-induced decreases in HDL are equivalent to low HDL within a given diet.

Why are the Japanese living longer?

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Declining trends in blood pressure level and the prevalence of hypertension, and changes in related factors in Japan, 1956-1980

Trends in age-specific and age-adjusted blood pressure and the prevalence of hypertension were obtained from the National Nutrition Survey of Japan, 1956-1980. The national trends in the age-adjusted blood pressure of people (30-69 years old) in Japan during the 1956-1980 period show an increasing pattern reaching a peak around 1964 followed by a decreasing pattern. To explore the possible factors which have contributed to the change in blood pressure levels, we analyzed the relationship between the blood pressure and several possible factors, including the rate of treatment for cardiovascular diseases (CVD) for men and women, annual salt and alcohol consumption per captia and body mass index (MBI) for men and women. Only alcohol consumption was considered in the analysis of men because women in Japan still tend to drink relatively little alcohol. In simple descriptive analyses, the increasing trend in the treatment rates of CVD seemed to be related to the decrease in the blood pressure level and in the prevalence rate of hypertension for both men and women. The impact of treatment rate seemed to overcome the adverse influence of the increasing trends in BMI. Recent decrease in salt consumption may account in part for the later period of the decreasing trends in blood pressure level and the prevalence of hypertension. In multiple regression analysis using these time series data, CVD, BMI and alcohol consumption were significantly related to blood pressure level and the prevalence of hypertension, although salt was not significant in these analyses.

Regional differences in stroke mortality and alcohol consumption in Japan

The relationship between alcohol consumption and stroke mortality in 1975 in 46 prefectures of Japan was investigated. This was done by adjusting salt intake and several socio-economic factors, i.e., the annual per capita income, the number of persons who received public aid, the number of tatamis (a Japanese traditional floor unit) per household, the unemployment rate, and the unmarried or divorce rate, using a stepwise multiple regression analysis. As dependent variables, the sex-specific and age-adjusted mortality for the middle-aged (35-59 years) and for all ages due to stroke were used. For men, alcohol consumption was significantly related to age-adjusted stroke mortalities for the middle-aged and for all ages independent of salt intake and several socio-economic factors. Alcohol consumption was more strongly related to age-adjusted stroke mortality for the middle-aged than for all ages. For women alcohol was weakly correlated with the stroke mortality of the middle-aged. Salt intake was significantly correlated with stroke mortality for women but not for men. Furthermore, the male: female ratios of the age-adjusted stroke mortality for the middle aged and for all ages were analyzed as well, because alcohol is mostly consumed by men in Japan, and it was expected that the sex ratios would be well correlated to alcohol consumption. The results were as expected. Therefore, it was suggested that the regional difference in stroke mortality in Japan may be explained in part by that of alcohol consumption.

Mortality rates for farmers and fishermen in Japan compared with England and Wales

Life tables for all causes of death for farmers and fishermen in Japan have been compared with those for England and Wales. Considering all causes of death, there are no occupational differences between farmers and fishermen in Japan. On the other hand, there are large occupational differences indicating that fishermen are worse off than farmers in England and Wales. Standardized mortality ratios (SMR) for each disease in terms of occupation have also been compared in the two countries. The SMRs for leading causes of death in Japan, such as cerebrovascular disease, are significantly lower for fishermen than for farmers in Japan. On the contrary, SMRs for leading causes of death in England and Wales, such as ischemic heart disease and lung cancer, are significantly higher for fishermen than for farmers in England and Wales. However the SMRs for ischemic heart disease and lung cancer are significantly higher for fishermen than for farmers in both countries.

Alcohol intake and hypertension among urban and rural Japanese populations

A significant positive relationship was found between alcohol intake and blood pressure for men 40-69 years old living in urban Osaka (492 men) and in rural Akita (395 men), Japan, surveyed from 1975 to 1977. Both mean blood pressure and the prevalence of hypertension were related to alcohol intake in a graded fashion. Stepwise multiple regression also showed that both systolic and diastolic pressure were associated with alcohol intake independent of ponderosity index, serum cholesterol, triglycerides, hemoglobin, uric acid, smoking, and age. This cross-sectional study indicates a continuous--and not a threshold--relationship between alcohol and blood pressure, with the effect of even moderate consumption, e.g. 28-55 g per day (equivalent to about 2-4 U.S. drinks per day).