Associations between rice, noodle, and bread intake and sleep quality in Japanese men and women

Background

Previous studies have shown that a diet with a high-glycemic index is associated with good sleep quality. Therefore, we investigated the association of sleep quality with the intake of 3 common starchy foods with different glycemic indexes–rice, bread, and noodles–as well as the dietary glycemic index in a Japanese population.

Methods

The participants were 1,848 men and women between 20 and 60 years of age. Rice, bread, and noodle consumption was evaluated using a self-administered diet history questionnaire. Sleep quality was evaluated by using the Japanese version of the Pittsburgh Sleep Quality Index, and a global score >5.5 was considered to indicate poor sleep.

Results

Multivariate-adjusted odds ratios (95% confidence intervals) for poor sleep across the quintiles of rice consumption were 1.00 (reference), 0.68 (0.49–0.93), 0.61 (0.43–0.85), 0.59 (0.42–0.85), and 0.54 (0.37–0.81) (p for trend = 0.015); those for the quintiles of noodle consumption were 1.00 (reference), 1.25 (0.90–1.74), 1.05 (0.75–1.47), 1.31 (0.94–1.82), and 1.82 (1.31–2.51) (p for trend = 0.002). Bread intake was not associated with sleep quality. A higher dietary glycemic index was significantly associated with a lower risk of poor sleep (p for trend = 0.020).

Conclusion

A high dietary glycemic index and high rice consumption are significantly associated with good sleep in Japanese men and women, whereas bread intake is not associated with sleep quality and noodle consumption is associated with poor sleep. The different associations of these starchy foods with sleep quality might be attributable to the different glycemic index of each food.

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.

Association between a serum thyroid-stimulating hormone concentration within the normal range and indices of obesity in Japanese men and women

OBJECTIVE

This cross-sectional study investigated the associations between the serum thyroid-stimulating hormone (TSH) concentration and indices of obesity in middle-aged Japanese men and women.

METHODS

The participants were 2,037 employees (1,044 men and 993 women; age, 36-55 yr) of a metal products factory in Japan. Clinical examinations were conducted in 2009. We obtained a medical history and anthropometric measurements (body weight, body mass index [BMI] and waist circumference) and measured the serum TSH concentrations. The anthropometric indices were compared across serum TSH quartiles. The associations were evaluated separately according to the smoking status in men.

RESULTS

The mean body weight (kg), BMI (kg/m(2)) and waist circumference (cm) were 69.2, 23.7 and 83.2 in men and 55.3, 22.3 and 74.3 in women, respectively. Men with a higher TSH concentration had higher body weight and BMI values (p for trend=0.016 and 0.019, respectively), and these significant associations were observed even after adjusting for age, smoking status and other potential confounders. The TSH level was not associated with waist circumference. We found a significant interaction between the TSH level and the smoking status on body weight (p for interaction=0.013) and a significant association between the TSH level and body weight in nonsmokers, but not in current smokers. No significant associations were observed between the TSH level and the anthropometric indices in women.

CONCLUSION

Significant positive associations between the serum TSH concentration, body weight and BMI were detected in men only, and an interaction with the smoking status was observed for this association.

Long-chain n-3 polyunsaturated fatty acids intake and cardiovascular disease mortality risk in Japanese: a 24-year follow-up of NIPPON DATA80

BACKGROUND

Dietary intake of long-chain n-3 PUFA (LCn3FA) among Japanese is generally higher than that in Western populations. However, little is known whether an inverse association of LCn3FA with cardiovascular disease (CVD) risk exists in a population with higher LCn3FA intake.

OBJECTIVE

To investigate the association between LCn3FA intake and the long-term risk of CVDs in a Japanese general population.

METHODS

We followed-up a total of 9190 individuals (56.2% women, mean age 50.0 years) randomly selected from 300 areas across Japan and free from CVDs at baseline. Dietary LCn3FA intake was estimated using household weighed food records. Cox models were used to calculate multivariate-adjusted hazard ratios (HR) and confidence intervals (CI) according to sex specific quartiles of LCn3FA intake.

RESULTS

During 24-year follow-up (192,897 person-years), 879 cardiovascular deaths were observed. The median daily intake of LCn3FA was 0.37% kcal (0.86 g/day). Adjusted HR for CVD mortality was lower in the highest quartile of LCn3FA intake (HR 0.80; 95% CI 0.66-0.96) compared with the lowest quartile, and the trend was statistically significant (P = 0.038). The similar but statistically non-significant trends were observed for coronary heart disease death and stroke death. In analyses by age groups, the inverse associations of LCn3FA intake with the risk of total CVD death and stroke death were significant in younger individuals (30-59 years at baseline).

CONCLUSION

LCn3FA intake was inversely and independently associated the long-term risk of total CVD mortality in a representative sample of Japanese with high LCn3FA intake.

Sugar-sweetened beverage and diet soda consumption and the 7-year risk for type 2 diabetes mellitus in middle-aged Japanese men

PURPOSE

This cohort study investigated the association between sugar-sweetened beverage (SSB) and diet soda consumption and the incidence of type 2 diabetes in Japanese men.

METHODS

The participants were 2,037 employees of a factory in Japan. We measured consumption of SSB and diet soda using a self-administered diet history questionnaire. The incidence of diabetes was determined in annual medical examinations over a 7-year period. Hazard ratios (HRs) with 95 % confidence intervals (CIs) for diabetes were estimated after adjusting for age, body mass index, family history, and dietary and other lifestyle factors.

RESULTS

During the study, 170 participants developed diabetes. The crude incidence rates (/1,000 person-years) across participants who were rare/never SSB consumers, <1 serving/week, ≥ 1 serving/week and <1 serving/day, and ≥ 1 serving/day were 15.5, 12.7, 14.9, and 17.4, respectively. The multivariate-adjusted HR compared to rare/never SSB consumers was 1.35 (95 % CI 0.80-2.27) for participants who consumed ≥ 1 serving/day SSB. Diet soda consumption was significantly associated with the incident risk of diabetes (P for trend = 0.013), and multivariate-adjusted HRs compared to rare/never diet soda consumers were 1.05 (0.62-1.78) and 1.70 (1.13-2.55), respectively, for participants who consumed <1 serving/week and ≥ 1 serving/week.

CONCLUSIONS

Consumption of diet soda was significantly associated with an increased risk for diabetes in Japanese men. Diet soda is not always effective at preventing type 2 diabetes even though it is a zero-calorie drink.

How does fortification affect the distribution of calcium and vitamin B1 intake at the school lunch for fifth-grade children?

The purpose of this study was to estimate the usual intake distribution of calcium and vitamin B(1) of fifth-grade children based on a 3-d dietary survey and to assess nutrient intake using Dietary Reference Intakes (DRIs 2010). A cross-sectional study was undertaken from October 2007 to February 2008 in schools located in Tokyo and Okayama, Japan. A total of 94 fifth-grade children attending 5 elementary schools participated in the study. The weighed plate waste method and observation were used to collect data on the school lunches and dietary records by children, accompanied by photographs used to collect data on meals at home. The study lasted 3 d, 2 non-consecutive days with school lunches and 1 d without. The estimated proportion of subjects below the Estimated Average Requirement (EAR) for calcium intake with milk in the school lunch decreased by 40% compared to the calcium intake without milk in the school lunch. Vitamin B1 intake from less than 0.45 mg/1,000 kcal fortified rice was estimated to be 0%. The intake distribution of calcium has increased by 150 mg by taking milk and the intake distribution of vitamin B1 has increased 0.20 mg by taking fortified rice in the school lunch. Calcium and vitamin B1 intake in the school lunch has changed the distribution of calcium and vitamin B1 intake upward, and decreased the number of estimated subjects that were below EAR. However, the distribution was not shifted across the board and the shape of the distribution has changed.

Family history of diabetes, lifestyle factors, and the 7-year incident risk of type 2 diabetes mellitus in middle-aged Japanese men and women

Aims/Introduction

This cohort study of middle‐aged Japanese participants investigated the relationship between family history of diabetes, the incident risk of type 2 diabetes and the interaction of these variables with other factors.

Materials and Methods

Study participants were 3,517 employees (2,037 men and 1,480 women) of a metal products factory in Japan. Baseline health examinations included questions about medical history, physical examination, anthropometric measurements, questions about lifestyle factors, such as smoking, alcohol consumption and habitual exercise, and a self‐administered diet history questionnaire. Family history of diabetes was defined as having at least one‐first‐degree relative with diabetes. The incidence of diabetes was determined in annual medical examinations over a 7‐year period. Hazard ratios (HRs) for type 2 diabetes were estimated by Cox proportional hazards analysis.

Results

Of the 3,517 participants, 630 (18%) had a family history of diabetes mellitus. During the study, 228 participants developed diabetes. The age and sex‐adjusted HR for type 2 diabetes in participants with a family history of diabetes was 1.82 (95% confidence interval 1.36–2.43) as compared with those without a family history of diabetes. HRs did not change after adjustment for body mass index and lifestyle factors. We found no interactions with body mass index, insulin resistance, pancreatic β‐cell function or lifestyle factors.

Conclusions

Family history of diabetes was associated with the incident risk of diabetes, and these associations were independent of other risk factors, such as obesity, insulin resistance, and lifestyle factors in Japanese men and women.

Abstract WP205: Long-chain n-3 Polyunsaturated Fatty Acids Intake and Cardiovascular Disease Mortality Risk in a General Japanese Population: NIPPON DATA80

BACKGROUND: In Western populations, long-chain n-3 polyunsaturated fatty acid (LCn3FAs) intake was shown to be inversely associated with the risk of cardiovascular diseases, particularly that of cardiac disease. Dietary intake of LCn3FAs among Japanese is generally higher than those of Western populations due to their higher intake of fish and shellfish. However, little is known regarding whether an inverse association exists in a population with higher LCn3FAs intake. Furthermore, evidence for association with stroke risk has been limited.

OBJECTIVES: To investigate the association between LCn3FAs intake and the risk of cardiovascular diseases and stroke in a Japanese general population.

METHODS: We followed-up a total of 9,190 community-dwelling individuals (56.1% women, mean age of 50.0 years) randomly selected from 300 areas across Japan and free from cardiovascular diseases at baseline. Dietary LCn3FAs intake was estimated using household weighed food records. Cox models were used to calculate multivariable adjusted hazard ratios (HRs) and 95% confidence interval (95%CI) according to sex specific quartiles of LCn3FAs intake. HRs were adjusted for age, sex, cardiovascular risk factors, dietary sodium and other nutritional factors.

RESULTS: During 24 years of follow-up, 879 cardiovascular deaths were observed. The median daily intake of LCn3FAs was 0.37%kcal. Median value of the lowest quartile of LCn3FAs intake (0.18%kcal) in the present study was twice as high as the average intake in U.S. population. Adjusted HR for cardiovascular disease mortality was lower in the highest quartile of LCn3FAs intake (HR 0.80; 95%CI, 0.66-0.96) compared with the lowest quartile, and the trend was significant ( P =0.038). The similar but statistically non- significant trends were observed for cardiac death and stroke death.

CONCLUSIONS: In a representative sample of Japanese with high LCn3FAs intake, the risk of total cardiovascular disease mortality was inversely and independently associated with LCn3FAs intake, and the risk of stroke also showed similar tendency.

Abstract WP194: Impact Of Total Energy Intake On Stroke Mortality Is Greater Than That Of Coronary Heart Disease: A 24-year Follow-up Of Representative Japanese (NIPPON DATA80), 1980-2004

INTRODUCTION: Previous studies showed that calorie restriction decreased blood pressure and plasma lipid, and increased longevity. However, impact of total energy intake (EI) on mortality from cardiovascular disease (CVD) including types of CVD has not been studied. We assessed the hypothesis that lower EI was associated with decreased risk of CVD, coronary heart disease (CHD), and stroke mortality.

Methods: We studied the association between EI and mortality form all CVD, CHD, and stroke using the National Integrated Project for Prospective Observation of Noncommunicable Disease and Its Trends in the Aged (NIPPON DATA80) database with a 24-year follow-up. We followed a random sample of 8,825 Japanese aged ≥30 years (mean age, 50.0 years at baseline in 1980; 43.3% men) without history of CVD, kidney disease, or diabetes. Those with lack of information about EI or extreme EI (sex-specific intake of highest or lowest 0.5%) were also excluded. EI was calculated from a 3 days weighed food record method. We classified the participants into sex-specific quintiles of EI (the lowest quintile: men<2,025.1 kcal/day, women<1,627.0 kcal/day, the highest quintile: men≥2,776.8 kcal/day, women≥2,219.7 kcal/day). We used Cox proportional-hazards models to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for sex, age, body mass index, smoking, drinking, systolic blood pressure, blood glucose, and total cholesterol.

Results: Multivariate HR in the lowest quintile (in reference to the highest quintile) from all CVD was significantly decreased (HR: 0.78, 95%CI: 0.62-0.98). The association was more remarkable for stroke mortality (HR: 0.67, 95%CI: 0.48-0.93) than for CHD mortality (HR: 0.82, 95%CI: 0.49-1.37). After further adjustment of multivariate HRs for sodium/potassium ratio, we observed similar results.

Conclusion: A 24-year follow-up of NIPPON DATA80 demonstrated that lower EI was associated with decreased risk of CVD mortality: the association was more remarkable for stroke mortality than for CHD mortality.

Alcohol intake and the risk of hyperuricaemia: a 6-year prospective study in Japanese men

BACKGROUND AND AIMS

Since there is little information derived from prospective studies on the amount of alcohol drinking required to induce hyperuricaemia, we attempted to address this issue in a Japanese population.

METHODS AND RESULTS

A total of 3310 Japanese men aged 20-54 years that were free of hyperuricaemia were classified according to their alcohol intake per week at baseline. Incident hyperuricaemia, defined as >7.0 mg/dl and/or taking medication for hyperuricaemia, was assessed through annual heath examinations for 6 years after the baseline examination. During follow-up, 529 incident cases of hyperuricaemia occurred. There was a positive, dose-response relationship between alcohol intake and the risk of incident hyperuricaemia. The hazard ratio (95% confidence interval) for hyperuricaemia in drinkers compared with non-drinkers was 1.10 (0.85-1.42) for <10.0 drinks/week, 1.40 (1.07-1.84) for 10.0-19.9 drinks/week, 1.64 (1.23-2.21) for 20.0-29.9 drinks/week and 1.98 (1.40-2.80) for ≥30.0 drinks/week (one drink contained 11.5 g of ethanol) after adjusting for age, baseline serum uric acid, body mass index, smoking habits, exercise habits, serum creatinine, blood pressure, serum cholesterol and blood glucose. The fraction of hyperuricaemia in the population attributable to alcohol intake was 21.6%. A clear dose-response pattern was observed for both beer and sake, when the consumption of these two beverages was analysed separately.

CONCLUSION

Habitual alcohol intake significantly contributed to the development of hyperuricaemia in Japanese men, regardless of type of alcoholic beverage consumed. Therefore, it is essential to reduce excessive alcohol intake to prevent and manage hyperuricaemia.

Self-reported speed of eating and 7-year risk of type 2 diabetes mellitus in middle-aged Japanese men

OBJECTIVE

This cohort study investigated the association between eating speed and the incidence of type 2 diabetes in middle-aged Japanese men.

MATERIALS/METHODS

Participants were 2,050 male employees of a metal products factory in Japan. We measured self-reported categorical eating speed. The incidence of diabetes was determined in annual medical examinations over a 7-year period. The association between eating speed and the incidence of diabetes adjusted for multiple variables (age, family history of diabetes, smoking, alcohol drinking, habitual exercise, and presence of hypertension and hyperlipidemia) was evaluated using Cox proportional hazards models.

RESULTS

The prevalence of obesity (BMI≥25 kg/m(2)) across the categories of eating speed (slow, medium, and fast) was 14.6, 23.3, and 34.8%, respectively, and a faster eating speed was associated with a higher prevalence of obesity. During the study, 177 participants developed diabetes. Crude incidence rates (/1,000 person-years) across the three categories of eating speed were 9.9, 15.6, and 17.3, respectively. Multivariate-adjusted hazard ratios (95% CI) across the categories were 1.00 (reference), 1.68 (0.93-3.02), and 1.97 (1.10-3.55), respectively, and eating speed was associated with the risk of diabetes (p for trend=0.030). After further adjustment for BMI, a significant association was not observed.

CONCLUSIONS

Eating speed was associated with the incidence of diabetes. Since these associations were not significant after adjusting for BMI, eating speed may act via its effect on body weight. Eating speed is a controllable risk factor, and eating slowly could be an acceptable lifestyle intervention for the prevention of diabetes mellitus.

Methodological issues for a large-scale intervention trial of lifestyle modification: Interim assessment of the high-risk and population strategy for occupational health promotion (HIPOP-OHP) study

OBJECTIVE

To clarify the methodological issues for the High-risk and population Strategy for Occupational Health Promotion Study (HIPOP-OHP study), which is a 4-year non-randomized control trial, an interim assessment of male participants was performed 3 years after the baseline survey.

METHODS

We had approximately 2,500 and 4,000 participants in the intervention and control groups, respectively. The population measures and prevalence of risk factors at each year, and between the baseline and 4th examinations were compared between the two groups. The personal trends of returning participants who were in the study at the 1(st) and 4(th) examinations were also evaluated.

RESULTS

During the 3 years, an increase in serum HDL cholesterol (2.7 mg/dl), and a reduction in the prevalence of hypertriglycemia detected with fasting blood samples (3.6%) and current smokers (5.4%) were observed in the intervention group. The mean HDL cholesterol level was significantly higher in the intervention group than in the control group at the 4th examination, reversed from the baseline survey. The serum non-HDL cholesterol level was significantly increased only in the control group. There was also a significant increase in the prevalence of hypertriglycemia nad high plasma glucose detected with fasting blood samples in the control group. The return participation rate after 3 years was 72.2% for the intervention group and 74.9% for the control group. The above-mentioned changes for risk factors were mainly due to returning participants at each examination.

CONCLUSION

These interventional methods may be effective in improving overall cardiovascular risk factors in the population. However, the low return participation rate will dilute the effect of the intervention.

The evaluation of materials to provide health-related information as a population strategy in the worksite: The high-risk and population strategy for occupational health promotion (HIPOP-OHP) study

OBJECTIVE

To examine the effectiveness of newly developed materials for providing health-related information to the worksite population, we compared the amount of attention that employees paid to the materials.

METHODS

Study subjects were 2,361 employees in six companies participating in an intervention program between 2002 and 2003. Three kinds of media were used as tools for providing health information: [1] Point Of Purchase advertising menus (POP menus) were placed on all tables in company restaurants, [2] posters were put on walls and [3] leaflets were distributed at health-related events. One year or more after the introduction of these media, we compared the amount of attention paid to each type of medium.

RESULTS

Amongst the three types of media, the POP menu drew the most attention, although results were not consistent in all gender and company groups. Every piece of information provided by the POP menus was "always" or "almost always" read by 41% of the men and 51% of the women surveyed. The corresponding rate for posters was 30% in men and 32% in women. For leaflets, only 16% of men and 22% of women read almost all of the leaflets. More attention was paid to the POP menu when the sample was women, older, and ate at the company restaurant at least three times a week.

CONCLUSION

The POP menu may provide health-related information to a broader range of people than posters and leaflets, therefore, it is an effective material for population strategy.

Dietary glycemic index and risk of type 2 diabetes mellitus in middle-aged Japanese men

This cohort study investigated the association between dietary glycemic index (GI), glycemic load (GL), and the incidence of type 2 diabetes mellitus in middle-aged Japanese men, and the effect of insulin resistance and pancreatic B-cell function on the association. Participants were 1995 male employees of a metal products factory in Japan. Dietary GI and GL were assessed using a self-administered diet history questionnaire. The incidence of diabetes was detected in annual medical examinations over a 6-year period. The association between GI, GL, and the incidence of diabetes was evaluated using Cox proportional hazards models. During the study, 133 participants developed diabetes. Age- and body mass index-adjusted hazard ratios across the GI quintiles were 1.00 (reference), 1.62, 1.50, 1.68, and 1.80; and those of GL were 1.00 (reference), 1.07, 1.48, 0.95, and 0.98. The hazard ratio for the highest GI quintile was significantly greater than that for the lowest quintile. The influence of GI was more pronounced in the lowest insulin resistance subgroups. GI and pancreatic B-cell function were independently associated with the incidence of type 2 diabetes mellitus; participants with low B-cell function and the highest tertile of GI had the highest risk of diabetes. Dietary GI is associated with the incidence of diabetes in middle-aged Japanese men. GI and B-cell function were independently associated with incidence of diabetes.

Relationship between Dietary and Other Lifestyle Habits and Cardiometabolic Risk Factors in Men

BACKGROUND

Prevalence of men with cardiometabolic risk factors (CMRF) is increasing in Japan. Few studies have comprehensively examined the relation between lifestyles and CMRF.

METHODS

We examined the baseline data from 3,498 male workers ages 19 to 69 years who participated in the high-risk and population strategy for occupational health promotion (HIPOP-OHP) study at 12 large-scale companies throughout Japan. The physical activity of each participant was classified according to the International Physical Activity Questionnaire (IPAQ). Dietary intake was surveyed by a semi-quantitative Food Frequency Questionnaire. We defined four CMRF in this study as follows: 1) high blood pressure (BP): systolic BP ≥ 130 mmHg, or diastolic BP ≥ 85 mmHg, or the use of antihypertensive drugs; 2) dyslipidemia: high-density lipoprotein-cholesterol concentration < 40 mg/dl, or triglycerides concentration ≥ 150 mg/dl, or on medication for dyslipidemia; 3) impaired glucose tolerance: fasting blood sugar concentration ≥110 mg/dl; 4) obese: a body mass index ≥ 25 kg/m2.

RESULTS

Those who had 0 to 4 CMRF accounted for 1,597 (45.7%), 1,032 (29.5%), 587 (16.8%), 236 (6.7%), and 44 (1.3%) participants, respectively, in the Poisson distribution. Poisson regression analysis revealed that independent factors that contributed to the number of CMRF were age (b = 0.020, P < 0.01), IPAQ (b = -0.091, P < 0.01), alcohol intake (ml/day) (b = 0.001, P = 0.03), percentage of protein intake (b = 0.059, P = 0.01), and total energy intake (kcal)(b = 0.0001, P < 0.01). Furthermore, alcohol intake and its frequency had differential effects.

CONCLUSIONS

Alcohol intake, percent protein and total energy intake were positively associated, whereas drinking frequency and IPAQ were inversely associated, with the number of CMRF.

Amounts served and consumed of school lunch differed by gender in Japanese elementary schools

School lunches serve to improve nutritional status and to promote the health of children. The purpose of this study was to investigate the portion sizes of school lunches served and consumed in Japanese elementary schools. In addition, gender difference in servings and consumption were also studied. A cross-sectional study was undertaken between October 2007 and February 2008 in schools located in Tokyo and Okayama, Japan. A total of 192 fifth-grade children attending four elementary schools participated in this study. Weighed plate waste methods and observation were used to collect dietary data for two non-consecutive days. The proportion of children who chose staple foods along with main dishes and/or side dishes for at least one day was higher in boys than in girls (respectively, for staple food: 42.1% vs. 9.3%, for main dish and/or side dish: 68.4% vs. 44.3%, P < 0.001). The ratio of initial amount served to amount offered was 0.88 ± 0.11 for boys and 0.84 ± 0.10 for girls (P < 0.05). The ratio of amount consumed to amount offered was 1.04 ± 0.19 for boys and 0.88 ± 0.12 for girls (P < 0.001). Weight was related to amount consumed both in boys (r = 0.222, P < 0.05) and in girls (r = 0.201, P < 0.05). These findings suggest that the nutritional standards of school lunch programs should take into account gender differences. Clearly, boys were more likely to consume more than the initial amounts served due to their higher propensity to take second helpings. Boys feel few reservations about taking second helpings to adjust their total intake. However, school lunch plans should take into consideration girls' reluctance to do so, by serving appropriate initial portion sizes.

Homeostasis model assessment of insulin resistance and the risk of cardiovascular events in middle-aged non-diabetic Japanese men

AIMS/HYPOTHESIS

Little is known about the relationship between the HOMA of insulin resistance (HOMA-IR) and the risk of cardiovascular events in Asian populations, which have lower levels of HOMA-IR than Western populations. Accordingly, we determined the predictive value of HOMA-IR for cardiovascular risk in a Japanese population that was apparently free of diabetes, addressing whether insulin resistance itself increases cardiovascular risk independently of other relevant metabolic disorders.

METHODS

We followed 2,548 non-diabetic men aged 35 to 59 years for 11 years. The hazard ratios for the incidence of cardiovascular events due to increased HOMA-IR were estimated using a Cox proportional hazards model that was adjusted for potential confounding factors.

RESULTS

The multivariate-adjusted hazard ratio for cardiovascular events compared with the first quartile of HOMA-IR (<or=0.66) was 1.07 (95% CI 0.44-2.64) for the second (HOMA-IR 0.67-1.01), 1.36 (0.56-3.28) for the third (HOMA-IR 1.02-1.51) and 2.50 (1.02-6.10) for the fourth quartile (HOMA-IR >or=1.52). The hazard ratio associated with a one SD (0.61) increment in log-transformed HOMA-IR was 1.51 (1.13-2.02). A similar positive relationship was observed for coronary events and stroke. In addition, the relationship between HOMA-IR and cardiovascular risk was broadly similar in participants with and without hypertension, dyslipidaemia (elevated triacylglycerol and/or reduced HDL-cholesterol), abdominal obesity and current smoking.

CONCLUSIONS/INTERPRETATION

Increased HOMA-IR predicted subsequent cardiovascular events in non-diabetic Japanese men. The association was independent of traditional cardiovascular risk factors and other relevant metabolic disorders.

Dietary glycemic index, glycemic load and blood lipid levels in middle-aged Japanese men and women

AIMS

This study investigated the association between dietary glycemic index (GI)/glycemic load (GL) and serum lipids in middle-aged Japanese men and women.

METHODS

The study participants were employees of a metal products factory in Japan: 2,257 men and 1,598 women aged 35 years or older. Dietary GI and GL were assessed using a self-administered diet history questionnaire. Serum lipid levels, adjusted for age, body mass index, alcohol consumption, smoking, physical activity, menopause status, and dietary intake of total energy, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, cholesterol and fiber, were compared among GI/GL quintiles for each gender.

RESULTS

No significant associations were observed between GI and adjusted serum lipids in men or women. In contrast, GL was inversely associated with HDL-cholesterol in men and women (p for trend=0.001 for men and < 0.001 for women), and positively associated with non-HDL-cholesterol (p for trend=0.010), LDL-cholesterol (p for trend=0.035) and triglycerides (p for trend=0.011) in women; however, alcohol drinking affected these associations; there was no association between GL and serum lipids in male nondrinkers and between GL and LDL-cholesterol in female nondrinkers.

CONCLUSION

GL was inversely associated with HDL-cholesterol and positively associated with non-HDL-cholesterol in Japanese women. These associations in men were not observed in nondrinkers. A high-GL diet for women may have an atherogenic effect through these serum lipid abnormalities.

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.

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.