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

Relationship Between Hemoglobin Concentration and Cardiovascular Disease Mortality in a 25-Year Follow-up Study of a Japanese General Population - NIPPON DATA90

BACKGROUND

Deviations of hemoglobin from normal levels may be a factor in cardiovascular disease (CVD) risk; however, conclusive evidence is lacking. In addition, preclinical conditions may influence hemoglobin concentrations, but studies focusing on reverse causation are limited. Thus, we examined the relationship between hemoglobin concentrations and CVD mortality risk, considering reverse causation.

METHODS AND RESULTS

In a prospective cohort representative of the general Japanese population (1990-2015), we studied 7,217 individuals (mean age 52.3 years; 4,219 women) without clinical CVD at baseline. Participants were categorized into sex-specific hemoglobin quintiles (Q1-Q5) and data were analyzed using the Cox proportional hazards model adjusted for possible confounders. During a 25-year follow-up, 272 men and 334 women died from CVD. Adjusted hazard ratios for CVD mortality across sex-specific quintiles, using Q3 as the reference, were significantly higher for Q1 (1.40; 95% confidence interval [CI] 1.08-1.82) and Q5 (1.49; 95% CI 1.14-1.96), and remained significant after excluding deaths within the first 5 years of follow-up to consider reverse causation (1.35 [95% CI 1.02-1.79] and 1.45 [95% CI 1.09-1.94], respectively). A similar U-shaped association was seen between transferrin saturation levels and CVD mortality, but after excluding deaths within the first 5 years the association was significant only for Q1.

CONCLUSIONS

Low and high hemoglobin concentrations were associated with an increased risk of CVD mortality.

Association of Pro-Inflammatory Diet with Long-Term Risk of All-Cause and Cardiovascular Disease Mortality: NIPPON DATA80

AIM

A pro-inflammatory diet may increase the risk of cardiovascular disease (CVD) and all-cause mortality. However, this remains inconclusive as there is yet no study using a dietary record method that has been conducted in a large general population. Furthermore, an underestimation of the pro-inflammatory diet may exist due to the unmeasured effect of salt intake. Thus, in this study, we aimed to examine how pro-inflammatory diet is associated with the long-term risk of all-cause and CVD mortality in a representative Japanese population.

METHODS

A national nutrition survey was conducted throughout Japan in 1980. After considering the exclusion criteria, 9284 individuals (56% women aged 30-92 years) were included in this study. In total, 20 dietary parameters derived from 3-day weighed dietary records were used to calculate the dietary inflammatory index (DII). The causes of death were monitored until 2009. The Cox proportional hazards model was used to determine multivariable-adjusted hazard ratios (HRs). Stratified analysis according to salt intake level was also performed.

RESULTS

Compared with the lowest quartile of DII, multivariable-adjusted HRs (95% confidence intervals) in the highest quartile were 1.28 (1.15, 1.41), 1.35 (1.14, 1.60), 1.48 (1.15, 1.92), 1.62 (1.11, 2.38), and 1.34 (1.03, 1.75) for all-cause mortality, CVD mortality, atherosclerotic CVD mortality, coronary heart disease mortality, and stroke mortality, respectively. Stratified analysis revealed stronger associations among individuals with higher salt intake.

CONCLUSIONS

As per our findings, a pro-inflammatory diet was determined to be positively associated with the long-term risk of all-cause and CVD mortality in a representative Japanese population. Thus, considering both salt intake and pro-inflammatory diet is deemed crucial for a comprehensive assessment of CVD risk.

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.

Risk Factors That Most Accurately Predict Coronary Artery Disease Based on the Duration of Follow-up - NIPPON DATA80

BACKGROUND

This study assessed sex-specific time-associated changes in the impact of risk factors on coronary artery disease (CAD) mortality in a general population over long-term follow-up.Methods and Results:A prospective longitudinal cohort study was conducted on representative Japanese populations followed up for 29 years. Data from 8,396 participants (3,745 men, 4,651 women) were analyzed. The sex-specific multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of 4 risk factors (smoking, diabetes, serum total cholesterol [TC], and systolic blood pressure [SBP]) for CAD mortality were calculated at baseline and at 10, 15, 20, 25, and 29 years of follow-up. In men, smoking (HR 3.23; 95% CI 1.16-9.02) and a 1-SD increase in TC (HR 1.82; 95% CI 1.29-2.57) were strongly associated with a higher risk of CAD in the first 10 years, but this association decreased over time. Diabetes (HR 2.30; 95% CI 1.37-3.85) and a 1-SD increase in SBP (HR 1.23; 95% CI 1.00-1.50) were strongly correlated with a higher risk of CAD after 29 years). In women, diabetes was correlated with CAD after 20 years (HR 2.53; 95% CI 1.19-5.36) and this correlation persisted until after 29 years (HR 2.47; 95% CI 1.40-4.35).

CONCLUSIONS

The duration of follow-up needed for the accurate assessment of risk factors for CAD mortality varies according to risk factor and sex.

Association of Red Meat Intake with the Risk of Cardiovascular Mortality in General Japanese Stratified by Kidney Function: NIPPON DATA80

The consumption of red meat has been recommended for individuals with reduced kidney function. However, red meat intake was recently suspected to increase cardiovascular disease (CVD) risk. We evaluated the association of red meat intake with CVD mortality risk in Japanese with/without reduced kidney function. Overall, 9112 participants of a Japanese national survey in 1980, aged ≥30 years, were followed for 29 years. Red meat intake was assessed using weighed dietary record. Cox proportional hazards models were used to estimate the hazard ratio (HR) of CVD mortality according to sex-specific tertiles of red meat intake. We also performed stratified analyses with/without reduced kidney function defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m². Red meat intake was not associated with CVD mortality risk in men and women. In stratified analyses, the HR of the highest compared with the lowest tertile of red meat intake was lower only in women with reduced kidney function (0.67, 95% confidence interval 0.46-0.98). In conclusion, there were no clear associations between red meat intake and CVD mortality risk in Japanese population; however, a higher intake of red meat was associated with lower risk of future CVD mortality in women with reduced kidney function.

Relationship Between Calcium Intake and Impaired Activities of Daily Living in a Japanese Population: NIPPON DATA90

Background

Major reasons for long-term care insurance certification in Japan are stroke, dementia, and fracture. These diseases are reported to be associated with calcium intake. This study examined the association between calcium intake and impaired activities of daily living (ADL) using the data from NIPPON DATA90, consisting of representative sample of the Japanese population.

Methods

A population-based nested case-control study was performed. A baseline survey was conducted in 1990, followed by ADL surveys of individuals ≥65 years old in 2000. Individuals with impaired ADL and selected age- and sex-matched controls were then identified. We obtained 132 pairs. Calcium intake was energy-adjusted using the residual method. The association between calcium intake and impaired ADL was examined using conditional logistic regression models. To assess the accuracy of the estimates, we conducted bootstrap analyses.

Results

The adjusted odds ratios (ORs) for impaired ADL compared with the group with a calcium intake of <476 mg/day were 0.72 (95% confidence interval [CI], 0.37–1.40) for the 476–606 mg/day group and 0.44 (95% CI, 0.21–0.94) for the ≥607 mg/day group in 2000 (P for linear trend = 0.03). After the bootstrap analyses, the inverse relationship unchanged (median OR per 100-mg rise in calcium intake, 0.87 [1,000 resamplings]; 95% CI, 0.76–0.97).

Conclusions

After bootstrap analyses, calcium intake was inversely associated with impaired ADL 10 years after the baseline 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.

Relationship between carbohydrate and dietary fibre intake and the risk of cardiovascular disease mortality in Japanese: 24-year follow-up of NIPPON DATA80

BACKGROUND/OBJECTIVES

The association between carbohydrate intake and cardiovascular disease (CVD) risk has been investigated, but whether the quality of carbohydrate is more important than its amount is not known. We examined the associations between intake of dietary fibre (DF), carbohydrate, available carbohydrate, and starch with long-term CVD mortality in a Japanese population.

SUBJECTS/METHODS

We prospectively followed 8925 participants (3916 men and 5009 women) aged 30-79 years without CVD at baseline who participated in the National Nutrition Survey in Japan. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) and their 95% confidence intervals (CIs) for CVD mortality by quartiles of exposure variables.

RESULTS

During 24 years of follow-up, 823 CVD deaths were observed. In men, the multivariable-adjusted HR for CVD mortality was lower in the highest quartile of DF intake (HR: 0.64; 95% CI: 0.47-0.87; P_trend = 0.007) compared with the lowest quartile. This association was not significant in women. Multivariable-adjusted HR for total stroke mortality was lower in the highest quartile of DF intake (HR: 0.61; 95% CI: 0.38-0.98; P_trend = 0.046) compared with the lowest quartile in women. Carbohydrate, available carbohydrate, and starch intake were not associated with CVD mortality.

CONCLUSIONS

Higher intake of DF was associated significantly with a lower risk of CVD mortality in men and lower risk of stroke mortality in women. Intake of carbohydrate, available carbohydrate, and starch were not associated with the risk of CVD mortality in men or women.

Dietary Inflammatory Index Positively Associated With High-Sensitivity C-Reactive Protein Level in Japanese From NIPPON DATA2010

Background

It has been reported that chronic inflammation may play an important role in the pathogenesis of several serious diseases and could be modulated by diet. Recently, the Dietary Inflammatory Index (DII^®) was developed to assess the inflammatory potential of the overall diet. The DII has been reported as relevant to various diseases but has not been validated in Japanese. Thus, in the present study, we analyzed the relationship between DII scores and high-sensitivity C-reactive protein (hs-CRP) levels in a Japanese population.

Methods

Data of the National Integrated Project for Prospective Observation of Non-communicable Disease and its Trends in the Aged 2010 (NIPPON DATA2010), which contained 2,898 participants aged 20 years or older from the National Health and Nutrition Survey of Japan (NHNS2010), were analyzed. Nutrient intakes derived from 1-day semi-weighing dietary records were used to calculate DII scores. Energy was adjusted using the residual method. Levels of hs-CRP were evaluated using nephelometric immunoassay. Multiple linear regression analyses were performed.

Results

After adjusting for age, sex, smoking status, BMI, and physical activity, a significant association was observed between DII scores and log(CRP+1) (standard regression coefficient = 0.05, P < 0.01). Although it was not statistically significant, the positive association was consistently observed in almost all age-sex subgroups and the non-smoker subgroup.

Conclusions

The current study confirmed that DII score was positively associated with hs-CRP in Japanese.

Vegetable Protein Intake was Inversely Associated with Cardiovascular Mortality in a 15-Year Follow-Up Study of the General Japanese Population

AIM

To examine the relationship between the intake of dietary vegetable protein and CVD mortality in a 15-year follow-up study of a representative sample of the Japanese population.

METHODS

A total of 7,744 participants aged 30 years or older (3,224 males and 4,520 females) who were free of CVD at baseline were included in this analysis. Vegetable protein intake (% energy) was assessed using a three-day semi-weighed dietary record at baseline. Multivariable-adjusted hazard ratios (HRs) were calculated using Cox's proportional hazards model after adjusting for confounding factors.

RESULTS

The total person-years studied were 107,988 with a mean follow-up period of 13.9 years. There were 1,213 deaths during the follow-up period, among which 354 (29.2%) were due to CVD. Vegetable protein intake was associated inversely with CVD and cerebral hemorrhage mortality, with the HRs for a 1% energy increment in vegetable protein intake being 0.86 (95% CI, 0.75-0.99) and 0.58 (95% CI, 0.35-0.95), respectively. In the subgroup analysis of participants with or without hypertension, the inverse association between vegetable protein intake and CVD mortality was more evident in the nonhypertensive group, with the HRs for CVD and stroke being 0.68 (95% CI, 0.50-0.94) and 0.50 (95% CI, 0.30-0.84), respectively.

CONCLUSIONS

Vegetable protein intake may prevent future CVD, particularly in nonhypertensive subjects in the Japanese population. However, further studies are necessary to examine the biological mechanisms of this effect.

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.

Associations of Overweight, Obesity, and Underweight With High Serum Total Cholesterol Level Over 30 Years Among the Japanese Elderly: NIPPON DATA 80, 90, and 2010

Background

The trend of association between overweight and high serum total cholesterol (TC) among the elderly is unclear. In addition, there is little evidence of risk of underweight for high TC. Therefore, we examined the trend of association of overweight or underweight with high TC among Japanese elderly people using nationwide population-based data.

Methods

Data of the National Survey on Circulatory Disorders and National Health and Nutrition Survey for 1980, 1990, 2000, and 2010 were used in the analysis. High TC was defined as 220 mg/dL and above. For participants aged ≥50 years, sex-specific odds ratios (ORs) of overweight or underweight compared with normal body mass index participants for high TC were calculated using a logistic regression model adjusted for age, smoking, drinking, exercise, food, and treatment of hyperlipidemia.

Results

A total of 5,734, 4,673, 5,059, and 2,105 participants enrolled in these surveys in 1980, 1990, 2000, and 2010, respectively. Although overweight was positively and significantly associated with high TC in 1980, the association has gradually weakened since (ORs in 1980 and 2010 were 2.44; 95% confidence interval [CI], 1.83–3.24 and 0.92; 95% CI, 0.66–1.27 among men and 1.43; 95% CI, 1.18–1.72 and 1.08; 95% CI, 0.81–1.44 among women, respectively). While underweight was inversely and significantly associated with high TC in 1980, the association also gradually weakened among women (ORs in 1980 and 2010 were 0.28; 95% CI, 0.12–0.60 and 0.37; 95% CI, 0.10–1.28 among men and 0.39; 95% CI, 0.26–0.57 and 0.96; 95% CI, 0.58–1.57 among women, respectively).

Conclusions

These findings provide evidence that high TC prevention efforts must expand the target to not only overweight but also to normal and underweight people.

Usefulness of a Short Dietary Propensity Questionnaire in Japan

Aim: There is a growing need for nutritional education for prevention and non-pharmacological treatment of risk factors for cardiovascular diseases (CVD). We compared the results of a short dietary propensity questionnaire (SDPQ) with those from the food frequency and quantity survey (FF Quantity), which had been previously quantitatively assessed by comparison with the 24-hr dietary recall (24hr-DR), to examine the usefulness of the SDPQ. The SDPQ was designed to assess dietary propensities of 12 food/nutrients relevant to CVD risk factors.

Methods: We conducted a dietary survey using the SDPQ on Japanese men and women. After 2–3 weeks, we conducted the FF Quantity survey with the same participants. For each of the 12 food/nutrient categories, the relationships between quintiles of results from the SDPQ and FF Quantity were examined. Results from 79 participants who completed both surveys were used.

Results: Spearman's correlation coefficients (r) were significant for all food/nutrient categories. Good correlations were found with alcohol (r = 0.792), starchy foods (r = 0.566), and milk and dairy products (r = 0.687), for which good correlations between the FF Quantity and 24hr-DR had been observed previously. Moderate correlations were found for vegetables (r = 0.386) and high-salt foods (r = 0.505), although the FF Quantity survey poorly correlated with the 24hr-DR.

Conclusion: The SDPQ may be useful for assessment of dietary propensities for alcohol, starchy foods, and milk and dairy products in Japan.

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.

High long-chain n-3 fatty acid intake attenuates the effect of high resting heart rate on cardiovascular mortality risk: a 24-year follow-up of Japanese general population

BACKGROUND

Increased resting heart rate (RHR) independently predicts cardiovascular mortality. Meanwhile, long-chain n-3 fatty acids (LCn3FAs) have a cardioprotective effect. Our aim was to evaluate whether higher LCn3FAs intake attenuates the elevated risk of cardiovascular mortality associated with increased RHR.

METHODS

We conducted a population-based 24-year prospective cohort study of Japanese, whose LCn3FAs intake is relatively high. Study participants included 8807 individuals aged 30-95 years from randomly selected areas across Japan without cardiovascular diseases and anti-hypertensive drugs at baseline. The primary endpoint was cardiovascular mortality, and the secondary endpoints were cardiac and stroke mortality during 24 years of follow-up. Individual dietary LCn3FAs intake was estimated from household-based 3-day weighed food records. RHR was obtained from 3 consecutive R-wave intervals on 12-lead electrocardiography. Cox models were used to estimate the multivariable hazard ratios (HRs) and 95% confidence intervals (95% CIs) adjusting for possible confounders.

RESULTS

During the follow-up period, 617 cardiovascular deaths were observed. The median daily intake of LCn3FAs was 0.37% kcal (0.86g/day). The interaction between dietary LCn3FAs intake and RHR in the risk of cardiovascular mortality was statistically significant (p=0.033). The risk of cardiovascular mortality was significantly higher in the low-intake group (<0.37%kcal) with an RHR >85beats/min (bpm) [hazard ratio (HR), 1.67; 95% confidence interval (CI), 1.15-2.43], but not in the high-intake group (≥0.37%kcal) with an RHR >85bpm (HR, 0.92; 95% CI, 0.61-1.38), compared with those in the high-intake group with an RHR <70bpm. Similar results were observed with stroke mortality, but not with cardiac mortality.

CONCLUSIONS

The risk of cardiovascular mortality associated with increased RHR is elevated in participants with low dietary LCn3FAs intake, but not in participants with high dietary LCn3FAs intake in a representative Japanese general population. These results suggest that high dietary LCn3FAs intake may prevent cardiovascular mortality associated with increased RHR.

Consumption of dairy products and death from cardiovascular disease in the Japanese general population: the NIPPON DATA80

Background

Recent Western studies show an inverse association between milk and dairy product intake and cardiovascular disease (CVD). We studied the association between consumption of milk and dairy products and CVD death in Japan.

Methods

Men and women aged 30 years or older were followed for 24 years. All had participated in a national nutrition survey in 300 health districts throughout Japan in 1980. The Cox proportional hazards model was used to assess mortality risk according to tertiles of milk and dairy product intake, with the high consumption group as reference. Hazard ratios (HRs) per 100-g/day increase in consumption were also estimated.

Results

During the 24-year follow-up period, there were 893 CVD deaths, 174 deaths from coronary heart disease (CHD), and 417 stroke deaths among 9243 participants. For women, the HRs for death from CVD, CHD, and stroke in the low consumption group were 1.27 (95% CI: 0.99–1.58; P for trend = 0.045), 1.67 (0.99–2.80; P = 0.02), and 1.34 (0.94–1.90; P = 0.08), respectively, after adjustment for age, body mass index, smoking status, alcohol drinking habits, history of diabetes, use of antihypertensives, work category, and total energy intake. With each 100-g/day increase in consumption of milk and dairy products, HRs tended to decrease for deaths from CVD (HR, 0.86; 95% CI, 0.74–0.99), CHD (0.73; 0.52–1.03), and stroke (0.81; 0.65–1.01) in women. No significant association was observed in men.

Conclusions

Consumption of milk and dairy products was inversely associated with CVD death among women in Japan.

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.

Protein intakes and serum albumin levels in a Japanese general population: NIPPON DATA90

Background

It is well-known that albumin is synthesized in the liver; serum albumin is a major component of serum proteins. However, it has not been well elucidated how dietary protein intakes are associated with serum albumin levels in general populations without extreme malnutrition. We cross-sectionally investigated in the representative Japanese the association between dietary protein intake and serum albumin levels.

Methods

A total of 7715 subjects (3220 men and 4495 women, aged 30 years or more) with measurement of serum albumin who participated in both the National Survey on Circulatory Disorders in 1990 and the National Nutrition Survey in 1990 were analyzed in the present analysis. Multiple-adjustments were performed with linear regression models to estimate the association between serum albumin levels and animal or vegetable protein intake adjusting for age and body mass index.

Results

The very weak positive association between animal protein and serum albumin levels was observed. On the other hand, there was no clear association observed between vegetable protein and serum albumin levels. Regardless of sex and models, age was inversely associated with serum albumin levels with statistically significance, and standardized coefficients of age were considerably larger in both sexes than other variables. Adjustment for body mass index hardly altered the coefficients of animal or vegetable protein intake, but adjustment for total cholesterol clearly attenuated the relationship between animal protein intake and serum albumin levels.

Conclusions

Present analysis indicated the possibility that animal protein intake was related with serum albumin levels, while vegetable protein intake was not related.

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.

Total energy intake and intake of three major nutrients by body mass index in Japan: NIPPON DATA80 and NIPPON DATA90

Background

This paper investigated the relationship between body mass index (BMI) and total energy intake as well as intake of three major nutrients in representative Japanese populations enrolled in the National Nutrition Surveys of Japan in 1980 and 1990.

Methods

A total of 10 422 participants (4585 men and 5837 women) and 8342 participants (3488 men and 4854 women) aged 30 or older from 300 randomly selected districts participated in the National Survey of Circulatory Disorders and the National Nutrition Survey in Japan in 1980 and 1990, respectively. The nutrition surveys were performed with weighing record method for three consecutive days to each household. Individually estimated total energy intake and intakes of three major nutrients (carbohydrate, protein, and fat) were compared by the categories of BMI and by 10-year age groups.

Results

In men, total energy intake (kcal/day), intakes of three major nutrients (g/day) and energy intake ratio from protein and fat (%) increased as BMI increased in each age group, whereas energy intake ratio from carbohydrate (%) decreased. In women, total energy intake, intakes of three major nutrients, and energy intake ratio from protein increased as BMI increased. Energy intake ratio from carbohydrate and fat decreased as BMI increased in women in 1990. When participants were categorized into quartiles according to total energy intake in each sex group, BMI increased as total energy intake increased in men in both 1980 and 1990.

Conclusions

A positive relationship was observed between body mass index and total energy intake in Japanese men. The relationship was weaker in Japanese women.

Calcium intake and associated factors in a general Japanese population: baseline data of NIPPON DATA80/90 and the National Nutrition Survey

Objective

The purpose of this study was to investigate the dietary calcium intake and associated other dietary factors among representative sample of Japanese general men and women.

Methods

Data was obtained by linking NIPPON DATA80 and 90 with the corresponding National Nutrition Surveys held in 1980 and 1990. We analyzed data for 10 422 subjects (4585 men and 5837 women) in NIPPON DATA80 and 8342 subjects (3488 men and 4854 women) in NIPPON DATA90. Calcium intake was calculated by age groups. Dietary calcium intake was classified into quintiles and physical, life-style, and dietary parameters were examined across the quintiles.

Results

For both men and women, calcium intake tended to be positively associated with age in NIPPON DATA80 and 90, and there were significant differences in estimated calcium intake between age groups. Calcium intake tended to be positively associated with age, protein, fat, saturated fat, vitamins A and C, sodium, potassium, and iron for men and women. Calcium intake also tended to be positively associated with intake of nuts, potatoes, sugar and sweeteners, soybeans and legumes, fruits, green and yellow vegetables, other vegetables, mushrooms, sea algae, fish and shellfish, eggs, and milk and dairy products for men and women.

Conclusions

The characteristics of calcium intake in Japanese people were able to be clarified by using the baseline data of NIPPON DATA and the National Nutrition Survey.

Association between food group intake and serum total cholesterol in the Japanese population: NIPPON DATA 80/90

Background

Dietary habit is one of the important determinants of health. Investigation of the association between diet and blood lipids at the food product level is more advantageous than that at the nutrient level because the results can be applied more directly to improving dietary habits for disease prevention.

Methods

The integrated datasets of the NIPPON DATA and National Nutrition Surveys in Japan conducted in 1980 and 1990 were used for analysis. The association between serum total cholesterol concentration and food group intake was examined by multiple linear regression analysis separately for sex and survey year with data adjusted for age, body mass index and total energy intake.

Results

Intakes of rice, sugar, sweets and snacks, fruit and vegetables other than green and yellow ones were lower and intakes of green and yellow vegetables, mushrooms, seaweed, eggs and milk were higher in the 1990 survey than in the 1980 survey. Intakes of meat, milk and eggs showed a positive association with serum total cholesterol concentration in both sexes while intake of legumes showed a negative association only in men in both the 1980 and 1990 surveys.

Conclusions

Sex- and age-specific food group intakes for 1980 and 1990 were identified, and positive and negative associations between serum total cholesterol concentration and food group intake were revealed in a representative sample of the Japanese population. The results provide some insights into the improvements in dietary habits that can be made for disease prevention in Japan.

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.

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.

Relationships between protein intake and renal function in a Japanese general population: NIPPON DATA90

BACKGROUND

It has been considered that reducing protein intake is one of important measures to delay the progression of chronic kidney disease (CKD). However, the relationship between protein intake and renal function is still uncertain, especially in relatively healthy general population.

METHODS

7404 individuals (3099 men and 4305 women) who participated in both National Survey on Circulatory Disorders and National Nutrition Survey in 1990 and were free from past history of renal diseases were included in the present study. We estimated sex-specific age- and multivariate-adjusted glomerular filtration rate (GFR) and odds ratios for the presence of CKD according to the quartiles of protein (total, animal, vegetable) intake per body weight (kg).

RESULTS

There were significant differences in each protein intake among the age groups in both men and women. Both participants with and without CKD took more protein intake than that of each recommended level. There were positive relationships between GFR and the quartiles of each protein intake in both sexes. The odds ratios for the presence of CKD were significantly decreased in the higher quartile of protein intake in women.

CONCLUSIONS

The higher protein intake was associated with higher GFR in both sexes and low prevalence of CKD in women. However, further studies are needed to conclude the relationships between protein intake and renal function.