Sex-specific relevance of diabetes to occlusive vascular and other mortality: a collaborative meta-analysis of individual data from 980 793 adults from 68 prospective studies

BACKGROUND

Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women than among men, but whether this increased relative risk in women exists across age groups and within defined levels of other risk factors is uncertain. We aimed to determine whether differences in established risk factors, such as blood pressure, BMI, smoking, and cholesterol, explain the higher relative risks of vascular mortality among women than among men.

METHODS

In our meta-analysis, we obtained individual participant-level data from studies included in the Prospective Studies Collaboration and the Asia Pacific Cohort Studies Collaboration that had obtained baseline information on age, sex, diabetes, total cholesterol, blood pressure, tobacco use, height, and weight. Data on causes of death were obtained from medical death certificates. We used Cox regression models to assess the relevance of diabetes (any type) to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke, or other atherosclerotic deaths) by age, sex, and other major vascular risk factors, and to assess whether the associations of blood pressure, total cholesterol, and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes.

RESULTS

Individual participant-level data were analysed from 980 793 adults. During 9·8 million person-years of follow-up, among participants aged between 35 and 89 years, 19 686 (25·6%) of 76 965 deaths were attributed to occlusive vascular disease. After controlling for major vascular risk factors, diabetes roughly doubled occlusive vascular mortality risk among men (death rate ratio [RR] 2·10, 95% CI 1·97-2·24) and tripled risk among women (3·00, 2·71-3·33; χ2 test for heterogeneity p<0·0001). For both sexes combined, the occlusive vascular death RRs were higher in younger individuals (aged 35-59 years: 2·60, 2·30-2·94) than in older individuals (aged 70-89 years: 2·01, 1·85-2·19; p=0·0001 for trend across age groups), and, across age groups, the death RRs were higher among women than among men. Therefore, women aged 35-59 years had the highest death RR across all age and sex groups (5·55, 4·15-7·44). However, since underlying confounder-adjusted occlusive vascular mortality rates at any age were higher in men than in women, the adjusted absolute excess occlusive vascular mortality associated with diabetes was similar for men and women. At ages 35-59 years, the excess absolute risk was 0·05% (95% CI 0·03-0·07) per year in women compared with 0·08% (0·05-0·10) per year in men; the corresponding excess at ages 70-89 years was 1·08% (0·84-1·32) per year in women and 0·91% (0·77-1·05) per year in men. Total cholesterol, blood pressure, and BMI each showed continuous log-linear associations with occlusive vascular mortality that were similar among individuals with and without diabetes across both sexes.

INTERPRETATION

Independent of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes to reduce smoking and obesity and use of cost-effective drugs that target major vascular risks (eg, statins and antihypertensive drugs) are important in both men and women with diabetes, but might not reduce the relative excess risk of occlusive vascular disease in women with diabetes, which remains unexplained.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union BIOMED programme, and National Institute on Aging (US National Institutes of Health).

Dietary patterns and risk of cardiovascular deaths among middle-aged Japanese: JACC Study

BACKGROUND AND AIMS

Little evidence showed the association between dietary patterns and cardiovascular disease among Japanese. The objective of this study was to examine whether dietary patterns are associated with cardiovascular disease among middle-aged Japanese.

METHODS AND RESULTS

At baseline (1988-1990), 26,598 men and 37,439 women aged 40-79 years enrolled in the Japan Collaborative Cohort (JACC) Study. During the follow-up through 2003, 578 men and 499 women died from stroke, and 272 men and 207 women died from coronary heart disease. We identified three major dietary patterns, 'vegetable', 'animal food' and 'dairy product', by factor analysis for both sexes. The multivariable hazard ratio (HR) and 95% confidence intervals of mortality from total cardiovascular disease in the highest versus lowest quintiles of the vegetable pattern were 0.93 (0.78-1.13), p for trend=0.73 for men and 0.82 (0.67-1.00), p for trend=0.04 for women. The respective HRs of mortality from stroke in the highest versus lowest quintiles of the dairy product pattern were 0.65 (0.49-0.86), p for trend=0.01 for men and 0.70 (0.51-0.97), p for trend=0.02 for women, and those of total cardiovascular disease were 0.89 (0.74-1.08), p for trend=0.23 for men and 0.76 (0.61-0.94), p for trend=0.01 for women. The animal food pattern was not associated with mortality from stroke, coronary heart disease or total cardiovascular disease for either sex.

CONCLUSION

We found that 'vegetable' and 'dairy product' patterns were associated with lower morality from cardiovascular disease, while the 'animal food' pattern was not associated with mortality from cardiovascular disease among Japanese.

Dietary intake of tin in Japan, and the effects on intake of canned food and beverage consumption

The study reported herein was initiated to examine dietary tin intake (Sn-D) in Japan to elucidate the possible effects of consumption of canned food (including beverages) on Sn-D, and to compare the intake among regions and between the two sexes in reference to the current provisional tolerable weekly intake and intake in other countries. Urinary tin levels (Sn-U) were also studied. Duplicate diet samples (24 h) together with records of food intake were collected in 1999-2004 from 111 adult residents in four areas of Japan. After exclusion of incomplete samples, 95 valid samples were subjected to determination of tin by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion. Among the 95 cases, 37 women additionally provided urine samples. Distribution of Sn-D was markedly skewed. Median Sn-D was 5.6 microg day(-1) for total subjects, which was about one-tenth of the values previously reported for the Japanese population; the difference was most probably attributable to the difference in the methods of determination. Consumption of canned foods led to a substantial increase in Sn-D. Thus, the median Sn-D for canned food consumers of 35.7 microg day(-1), was eight-fold higher than the median Sn-D for non-consumers of 4.5 microg day(-1). Sn-U (as corrected for creatinine concentration) distributed log-normally with a geometric mean of 2.0 microg (g cr)(-1). No effect of canned food consumption was evident on Sn-U. When compared internationally, Sn-D for the Japanese population was substantially lower than Sn-D for populations in other industrialized countries.

A validation study on a method to estimate nutrient intake by family members through a household-based food-weighing survey

The aim of the present study is to investigate the validity of a new method to estimate the food intake of individual subjects by a household-based dietary survey. The new method is based on the combination of household-based food weighing and approximating the proportions by which family members shared each dish or food in the household, which has been one of the components of the National Nutrition Survey, Japan, since 1995. We analyzed two sets of data from 64 volunteers (female students taking a dietitian course and their mothers) in 32 households by the approximated proportion method (method A) and the individual-based food weighing method (B) as a reference measurement. Energy and macronutrient intake by individual subjects estimated by method A was highly correlated to the corresponding values by method B (Pearson's correlation coefficients: r=0.90-0.92). Average energy intake was likely to be underestimated by method A compared with method B, being lower by 94 kcal (6.2% of the reference value in method B), at least in the young and middle-aged female adults that were the subjects of this study. When intake of boiled rice was separately analyzed, underestimation of energy intake by method A was 44 kcal, which contributed to approximately 50% of the total magnitude of the underestimation. The procedure manual for the National Nutrition Survey requests the participants to individually weigh the amount of boiled rice taken by family members in the household. However, this procedure is not observed in many actual settings. Therefore, following this procedure would be an effective measure to improve the accuracy of the dietary data.

Angiotensin converting enzyme genetic polymorphism is not associated with hypertension in a cross-sectional sample of a Japanese population: the Shibata Study

BACKGROUND

The studies on the association of deletion/ insertion (D/I) polymorphism of angiotensin converting enzyme (ACE) gene with blood pressure and hypertension reported contradictory results. Because there was no population-based study in Japan, we examine the hypothesized association in a cross-sectional sample of a Japanese cohort.

METHODS AND RESULTS

The blood pressure of 464 men and 876 women aged 40-80 years was measured, and their DNA was analyzed for ACE D/I genotypes. The prevalence of the D allele was 38.7 and 39.2% in men and women, respectively (overall 39%). There was a tendency for higher covariate (age, body mass index, albuminuria, hematocrit, alcohol consumption, smoking, diabetes mellitus, ischemic heart disease and antihypertensive medication) adjusted mean levels of diastolic blood pressure for the DD genotype in men but not in women. However, this tendency disappeared after dichotomization of blood pressure into diagnostic categories (normotension and hypertension). Results did not differ when the subjects were divided into two age groups (< or = 59 and > or = 60 years). Covariate-adjusted odds ratios for hypertension for presence of the D allele were close to the null value of one. ACE genetic variation accounted for only 0.1 and 0.7% of the inter-individual variation in systolic and diastolic blood pressure in men. These estimates were 0.2 and 0.1%, respectively, in women.

CONCLUSION

Although there is a tendency of higher diastolic blood pressure in men with DD genotypes, there is no convincing evidence that ACE genotypes are associated with hypertension in this Japanese population.

Serum vitamin C concentration was inversely associated with subsequent 20-year incidence of stroke in a Japanese rural community. The Shibata study

BACKGROUND AND PURPOSE

Epidemiological evidence suggests that vitamin C may decrease the risk of stroke. The purpose of the present study was to examine the association of serum vitamin C concentration with the subsequent incidence of stroke.

METHODS

In a Japanese rural community, a cohort of 880 men and 1241 women aged 40 years and older who were initially free of stroke was examined in 1977 and followed until 1997. The baseline examination included a measurement of serum vitamin C concentration. The incidence of stroke was determined by annual follow-up examinations and registry.

RESULTS

During the 20-year observation period, 196 incident cases of all stroke, including 109 cerebral infarctions and 54 hemorrhagic strokes, were documented. Strong inverse associations were observed between serum vitamin C concentration and all stroke (sex- and age-adjusted hazard ratios were 0.93, 0.72, and 0.59, respectively, for the second, third, and fourth quartiles compared with the first quartile; P for trend=0.002), cerebral infarction (0.71, 0.59, and 0.51; P for trend=0.015), and hemorrhagic stroke (0.89, 0.75, and 0. 45; P for trend=0.013). Additional adjustments for blood pressure, serum total cholesterol, body mass index, physical activity, smoking, alcohol drinking, antihypertensive medication, atrial fibrillation, and history of ischemic heart disease did not attenuate these associations markedly.

CONCLUSIONS

Serum vitamin C concentration was inversely related to the subsequent incidence of stroke. This relationship was significant for both cerebral infarction and hemorrhagic stroke. Additional mechanistic hypotheses may be required to explain our findings.

Population attributable fraction of stroke incidence in middle-aged and elderly people: contributions of hypertension, smoking and atrial fibrillation

We determined the population attributable fraction (PAF) of stroke due to hypertension (HT), atrial fibrillation (Af) and smoking in a Japanese community. Residents of Shibata (n = 2,302) who were surveyed initially in 1977 were followed until 1997. Two hundred and thirteen first strokes occurred. Among those 40-64 years of age, the risk ratio (RR) of Af was 11.24, followed by untreated HT (3.61), uncontrolled HT (3.69) and smoking (1.84). The PAFs, however, were 14.9% for smoking, 13.5% for untreated HT, 8.6% for uncontrolled HT and 3.6% for Af. Among those over 65 years, only Af was significant (RR 3.89) and the PAF was 6.0%. Determination of PAFs is also essential for designing effective stroke prevention programs in communities.

Age-dependent association of apolipoprotein E genotypes with stroke subtypes in a Japanese rural population

BACKGROUND AND PURPOSE

The association between apolipoprotein E (apoE) polymorphisms and stroke has been controversial. These controversies may be due to inaccurate classification of stroke and differences in age ranges. We investigated the association between apoE genotypes and stroke subtypes (confirmed by CT or MRI findings) by case-control study in a Japanese rural population.

METHODS

First-ever-stroke patients (n=322; cerebral infarction, n=201, intracerebral hemorrhage, n=84, and subarachnoid hemorrhage, n=37) aged 40 to 89 years were recruited from Hokuetsu Hospital, Japan. Healthy controls (n=1126) were selected from the general population in the same area. ApoE genotypes were determined by restriction fragment-length polymorphism analysis.

RESULTS

Compared with apoE epsilon3/epsilon3 subjects, epsilon2 carriers had a 2-fold risk of cerebral infarction (OR 1.9, 95% CI 1.1 to 3.2). Among cerebral infarction patients, epsilon2 carriers had increased risks of cortical infarction (OR 2.4, 95% CI 1.3 to 4.6) (an anatomic subtype) and atherothrombosis (OR 3.9, 95% CI 1.7 to 9.0) and cardioembolism (OR 4.9, 95% CI 1.6 to 14.4) but not lacunar infarction (clinical subtypes). ApoE epsilon4 carriers had a 2. 5-fold risk of subarachnoid hemorrhage (OR 2.5, 95% CI 1.1 to 5.4). ApoE epsilon2/epsilon2 subjects had an increased risk of intracerebral hemorrhage (OR 4.4, 95% CI 1.0 to 19.7). ApoE epsilon3/epsilon4 subjects showed approximately 2-fold increased risk of atherothrombosis (OR 2.1, 95% CI 1.0 to 4.1) and intracerebral hemorrhage (OR 1.8, 95% CI 1.0 to 3.3). The association between epsilon2 and stroke was accentuated in subjects aged 70 years or older but not in those aged 40 to 69 years.

CONCLUSIONS

Our study suggests that apoE epsilon2 is a risk factor for atherothrombosis, cardioembolism, and intracerebral hemorrhage, whereas epsilon4 is a risk factor for atherothrombosis, intracerebral hemorrhage, and subarachnoid hemorrhage. The occurrence of stroke may be affected by interaction between age and apoE gene polymorphisms.

An inverse relationship between serum vitamin C and blood pressure in a Japanese community

To examine the relationship between serum vitamin C concentration and blood pressure level, a cross-sectional study was conducted. The subjects were 919 men and 1,266 women aged 40 years and over in a Japanese provincial city, Shibata, Niigata Prefecture. The mean and standard deviation of systolic blood pressure (SBP) were 134.0 +/- 20.0 mmHg for men and 128.3 +/- 20.8 mmHg for women, and those of diastolic blood pressure (DBP) were 81.0 +/- 11.7 mmHg and 75.8 +/- 11.4 mmHg, respectively. The mean and standard deviation of serum vitamin C were 42.5 +/- 18.6 mumol/L for men and 56.8 +/- 16.5 mumol/L for women. SBP and DBP were both inversely correlated with serum vitamin C concentration. The means of SBP or DBP were calculated for quartiles of serum vitamin C, and the significant inverse relationship was observed in any sex and age group. The inverse association persisted after adjustment for possible confounders: body mass index, serum total cholesterol, alcohol consumption, smoking, physical activity, antihypertensive medication, and dietary intake of salt, calcium, and potassium. Serum vitamin C appeared to be inversely related with both SBP and DBP in this Japanese population, although further intervention and experimental studies were required to establish the cause-effect relationship.

Association of apolipoprotein genetic polymorphisms with plasma cholesterol in a Japanese rural population. The Shibata Study

The association between apolipoprotein (apo) genetic polymorphisms and lipid phenotypes remains to be determined because such studies have reported contradictory results. We have measured plasma total cholesterol (TC) and HDL cholesterol (HDL-C) in a cross-sectional sample of 1328 (462 men and 866 women) Japanese (aged 40 to 80 years) and analyzed their DNA for the following genotypes: apoA1-C3 Msp I and Sst I sites; apoB signal peptide insertion/deletion, Xba I site and 3' variable number of tandem repeats (VNTR); and apoE. Using multivariate analyses (ANOVA) we found that (1) the polymorphisms of apoA1-C3 and apoB genes are not significantly associated with TC or HDL-C and (2) the polymorphism of the apoE gene is significantly related with TC and the TC:HDL-C ratio. The epsilon 2 carriers have lower levels of TC and a lower TC:HDL-C ratio, epsilon 3 carriers have intermediate levels, and epsilon 4 carriers have higher levels. These findings held whether sexes were analyzed separately or together. Although an opposite trend in HDL-C levels was observed, it did not reach the level of statistical significance. Multiple regression analyses have shown that apoE polymorphism accounts for about 2.3% of the variation in TC and TC:HDL-C ratio irrespective of sex. When the subjects are divided into two groups according to their age (< or = 59 and > or = 60 years old), the effect of apoE alleles on serum cholesterols appears to be diluted in the younger age group whereas it appears to be accentuated in the older group for both sexes. Our findings suggest that among the apo genetic polymorphisms examined, the apoE gene may be considered as a possible candidate for the "high-risk" strategy of atherosclerosis prevention in the Japanese population.

Dietary lipids and incidence of cerebral infarction in a Japanese rural community

OBJECTIVE

To assess the relationship between dietary lipids and incidence of cerebral infarction in a Japanese rural population.

DESIGN

A cohort study from July 1977 through December 1992.

SETTING

Akadani-Ijimino (A-I) district, Niigata Prefecture, Japan.

SUBJECTS AND METHODS

All the residents, 1,182 men and 1,469 women, aged 40 years and over. Out of these members, 954 men and 1,329 women who were initially free of stroke completed a semiquantitative food frequency questionnaire in 1977, and were then subjected to a follow-up for 15.5 years. The occurrence of stroke was determined by the annual follow-up examination and registry. Dietary lipid was adjusted for total energy or fat intake by the residual method. Sex- and age-stratified and blood pressure- and atrial fibrillation-adjusted relative risk for cerebral infarction was estimated by the Cox proportional hazard model.

RESULTS

There were 75 new cases of cerebral infarction during the observation period. The relative risk for cerebral infarction was less than one in the highest quartile level of total fat, saturated fatty acids (S), Keys score and westernized dietary pattern: 0.68-0.94. It ranged between 1.36 and 1.57 in the highest level of polyunsaturated (P), n-3 and n-6 fatty acids, and P/S ratio.

CONCLUSION

This study suggests the possibility that the traditional Japanese diet, very low fat intake, was likely to increase the risk of stroke through the low level of serum cholesterol as an intermediary factor.

A 15.5-year follow-up study of stroke in a Japanese provincial city. The Shibata Study

BACKGROUND AND PURPOSE

Change toward Western lifestyles, particularly during the high economic growth period (approximately 1960 to 1975), dynamically altered stroke frequency and the distribution of risk factors in the Japanese. We reexamined their association after this environmental change by a cohort study.

METHODS

The cohort (2302 subjects) comprised residents aged 40 years or older of the Akadani-Ijimino district in Shibata City, Niigata Prefecture, Japan, who were followed up from 1977 for 15.5 years.

RESULTS

Crude incidence rates per 1000 person-years for all strokes were 5.22 for men and 4.36 for women (3.02 and 2.18 for cerebral infarction, 0.65 and 1.06 for intracerebral hemorrhage, and 0.41 and 0.34 for subarachnoid hemorrhage, respectively). Multivariate analyses performed with the Cox proportional hazard model revealed these risk factors to be independently significant: for cerebral infarction in men, age, blood pressure, atrial fibrillation, albuminuria, funduscopic abnormality, and current smoking: for cerebral infarction in women, age, atrial fibrillation, and history of ischemic heart disease; for intracerebral hemorrhage in men, age and funduscopic abnormality; for intracerebral hemorrhage in women, age, blood pressure, and light physical activity; for all strokes in men, age, blood pressure, atrial fibrillation, albuminuria, funduscopic abnormality, current smoking, and heavy physical activity; and for all strokes in women, age, atrial fibrillation, and light physical activity.

CONCLUSIONS

Most traditional risk factors, including blood pressure and its related organ diseases, were confirmed, but serum total cholesterol had almost no effect. Physical activity had both negative and positive effects on stroke risk. In these findings, however, some differences related to sex were also observed.

Development of a food frequency questionnaire in Japan

The three-consecutive-day weighing method, in which foods as raw materials are weighed separately before they are cooked, is the most popular dietary assessment method among Japanese dietitians, because this dietary survey method has been adopted in the national nutrition survey for half a century. Under such circumstances, there have been only a few studies aiming to develop and validate a food frequency questionnaire (FFQ) method. The food list of a few FFQs ever used dealt with individual food items alone, but not mixed dishes. Therefore, a frequency questionnaire was very difficult for people not involved in cooking daily to answer. In order to enable subjects to answer a questionnaire more accurately, a new FFQ which has a food list with 122 single foods and recipes was developed. These foods and recipes were identified from 805 24hr-recalls of males and females aged 40-69 years old in Shiso County, Hyogo Prefecture, Japan. During consecutive 56 or 63 days, 67 junior college students in a dietitian course recorded their diet intake. Within a week after the diet record, they answered the newly developed FFQ. Pearson correlation coefficients between energy adjusted nutrient intakes assessed from the FFQ and those from dietary records were calculated. These correlation coefficients ranged from 0.21 for retinol potency to 0.74 for calcium. These data indicate that the newly developed FFQ provides a useful measurement of many nutrient intakes over a two-month period.

A brief review of epidemiological studies on ischemic heart disease in Japan

The age-adjusted death rate from ischemic heart disease in Japan is the lowest among developed countries and the rates have decreased since 1970. The incidences of myocardial infarction in selected populations ranged between 0.12 and 2.56 per 1,000 for middle-aged males, and between 0.00 and 1.52 per 1,000 for females. The incidences of sudden death within 24 hours were from 0.00 to 1.58 per 1,000 for males and from 0.00 to 0.76 per/1,000 for females. The incidences in Japanese populations appeared to be far below those in Western populations. In the Cox proportional hazard regression model, hypertension and smoking were selected as independent risk factors for myocardial infarction in an agricultural district. It was noteworthy that the level of serum cholesterol was not associated with development of myocardial infarction in rural areas. No positive relation between dietary fat and serum cholesterol was observed in school children, suggesting that growth, sexual maturation and others might be confounding variables between them. The levels of serum cholesterol for females were more affected by menopause than those of blood pressures and body mass index. Although some polymorphisms in selected candidate genes appeared to be associated with some serum lipids and apolipoproteins, the effect of individual RFLP on the inter-individual variations in serum traits was relatively subtle in comparison with that of lifestyle factors.

A 15.5-year cohort study on risk factors for possible myocardial infarction and sudden death within 24 hours in a rural Japanese community

A 15.5-year follow-up study of ischemic heart disease among residents 40 years and older in a rural community, A-I district, Shibata City, Niigata Prefecture, Japan, was completed in 1992. The response rate for the initial examination was 84.5% of 1,182 men and 92.6% of 1,469 women. Nine hundred and eighty-five men and 1,344 women who were initially free of ischemic heart disease were followed from July 1977 through December 1992. The person-year incidence of possible myocardial infarction (PMI) was 1.01 per 1,000 for men and 0.59 for women, and that of sudden death within 24 hours (24SD) was 1.08 for men and 0.64 for women. In the sex-, and age-stratified univariate analyses by the Cox proportional hazard regression model, statistically significant relative risk of PMI was observed for systolic (SBP), diastolic (DBP) and mean blood pressure (MBP), body mass index and smoking. For 24SD, DBP and albuminuria were selected as significant risk factors. In the multivariate analyses, MBP and smoking were selected as independent risk factors for PMI. No significant association of any factor with 24SD was detected. The influence of serum cholesterol on occurrence of PMI appeared to be subtle.

Trends in death and consultation rates of ischemic heart disease in Japan and the risk factors in a rural community

In Japan, the age-adjusted death rate from ischemic heart disease has decreased for both male and female since 1970, although the rate appears to be slightly affected by mortality from senility without mention of psychosis, "cardiac insufficiency", and sudden death in elderly persons. On the other hand, consultation rate has shown an increase, suggesting an increase in the number of recovered patients and a lengthening in the duration of ischemic heart disease from onset to termination by CCU treatment. A 7.5-year prospective study of ischemic heart disease (myocardial infarction + angina pectoris on effort + sudden death) among residents 40 years and older was conducted at a rural community, Akadani-Ijimino district in Niigata Prefecture. Statistically significant risk factors appeared to be age, hypertension, ECG abnormalities and fuduscopic changes. Even in 1977-1984 when Japanese dietary habits were westernized, neither hyperlipidemia nor obesity was related to the development of ischemic heart disease in this agricultural district. Statistically significant risk ratios were not observed for any nutrient or food, although the ratio for animal fat, calcium, salted vegetables and caloric percent of animal protein was more than one respectively.

Studies of nitrogen balance in male highlanders in Papua New Guinea

Nitrogen metabolism in Papua New Guinea highlanders was studied by examining their nitrogen balance when they ate their usual diet (experiment 1) or an experimental diet (experiment 2). Studies were made on 39 male highlanders between October and December in 1980 and 1982. In experiment 1, the average protein and energy intakes (mean +/- SD) for three consecutive days of usual diets were 116.2 +/- 31.2 mg N/kg body weight and 46.9 +/- 8.9 kcal/kg body weight in 1980 and 143.5 +/- 54.8 mg N/kg body weight and 47.3 +/- 10.5 kcal/kg body weight in 1982, and thus the nitrogen balances were 27.7 +/- 28.3 and 18.4 +/- 24.2 mg N/kg body weight, respectively. Most dietary protein and energy was derived from sweet potatoes and other vegetable foods, but between 1980 and 1982 the diet changed slightly with increased consumption of imported foods such as rice and canned fish. In the second experiment, when 10 highlanders were given adequate protein diet (about 200 mg N/kg body weight and about 44 kcal total energy/kg body weight for 13 d, much of the dietary nitrogen was retained in their bodies (45.1 +/- 19.3 mg N/kg body weight). When another group of men were fed a sweet-potato diet (81.1 mg N/kg body weight for 8 d followed by a low protein sweet-potato diet containing only 42 mg N/kg body weight with 50 kcal/kg body weight for 14 d, nitrogen true digestibility and net protein utilization increased and their nitrogen balance showed no significant change (-11.0 +/- 5.6 mg N/kg body weight).(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiologic studies of stroke in Shibata, a Japanese provincial city: preliminary report on risk factors for cerebral infarction

A 6.5-year prospective study of cerebral infarction among residents 40 years and older was conducted at the Akadani-Ijimino district in Shibata City, Niigata Prefecture, Japan. The response rate for the initial examination was 85% of 1,182 males and 93% of 1,469 females. Nine hundred and sixty males and 1,339 females who were initially free of stroke were followed up from July 1977 through December 1983. Statistically significant risk factors for cerebral infarction appeared to be age, elevated blood pressure, high R, ST-T changes and atrial fibrillation on ECG, and albuminuria. The ECG abnormalities and albuminuria were due to the high blood pressure persisted over a long period of time. The strength of association of blood pressure with cerebral infarction got weak in comparison with other factors, and funduscopic changes which had been regarded as a risk factor for stroke in 1965-1974 did not reach statistical significance because of the spread of the community-based hypertension control. Even in 1977-1983 when Japanese dietary habits were westernized, neither hyperlipidemia nor obesity appeared to be related to the development of cerebral infarction.

Utilization of urea nitrogen in Papua New Guinea highlanders

The utilization of urea nitrogen was examined in 10 healthy adult men from a village near Lufa, in the Eastern Highlands Province of Papua New Guinea. The staple diet of these men was sweet potatoes. [15N]urea was used as tracer for urea released into their intestinal tracts and the utilization of the urea-N was estimated from the trend of 15N. The men were orally given [15N]urea at the beginning of the study and then their daily protein intake, serum protein levels, 15N excretion in the feces and urine, 15N retention in the whole body and 15N incorporation into serum protein were examined. Their daily protein intake (32.2 +/- 8.6 g/day) was low, but their serum protein level (8.05 +/- 0.41 g/100 ml) was within the normal range. 15N retention in the whole body on day 3 was estimated to be 35.4 +/- 20.2% of the total amount administered, calculated from the recoveries in the feces (1.64 +/- 0.85%) and urine (63.0 +/- 20.5%) on days 1-3. The utilization of urea nitrogen in Papua New Guinea highlanders was confirmed from the finding of 15N incorporation into serum proteins on day 3 (0.008 +/- 0.005 atom% excess). This incorporation was negatively correlated with the urinary nitrogen excretion and serum protein level. This correlation suggests that Papua New Guinea highlanders with low urinary nitrogen excretion or a low level in serum protein, who are in a poor state of protein nutrition, tend to utilize more urea nitrogen for the synthesis of serum protein.

Blood status and serum free amino acids in Papua New Guinea highlanders

Hematological values and serum amino-acid concentrations were measured in 17 healthy male adult Papua New Guinea highlanders who live on a sweet-potato staple diet. Hematological values were within the normal range, except for a low serum urea concentration. The concentrations of serum threonine, valine, isoleucine, leucine and tyrosine were significantly lower, and those of arginine, glutamate, glycine and alanine were significantly higher, than in Japanese controls. These amino acid patterns in the serum of Papua New Guinea highlanders are an indication of low protein nutrition and adequate energy supply. Some essential amino acid and urea concentrations in the serum of nine Papua New Guinea subjects fed on an adequate protein diet (1.3 g/kg body weight, about twice their habitual diet) for 13 days were significantly increased but were still significantly lower than those of Japanese subjects. Serum alanine decreased on an adequate protein diet. These results show that amino acid uptake and utilization by peripheral tissues may be accelerated on an adequate protein diet. Blood status and serum amino acid concentrations did not show any change except for urea and some amino acids, when five Papua New Guinea highlanders were fed on a low protein diet (0.6 g/kg) consecutively for 13 days.

Secular trends in mortality for cerebrovascular diseases in Japan, 1960 to 1979

In Japan the age-adjusted death rate from cerebrovascular diseases has decreased for both males and females since 1965. This downward trend accelerated in 1971. This is not due to artifacts such as changes in diagnostic methods of stroke and in rules for coding cause of death on death certificates. The progress and spread of detection, treatment and control of hypertension appears to have been the greatest contributing factor. Furthermore, improvement in the dietary habits, that is, a decrease in salt intake and an appropriate increase in the amount of animal fat and protein taken are also considered to have contributed to the decline in stroke mortality. The regional difference in the standardized mortality ratio for stroke markedly observed in 1960 was still seen even in the 1970's, but the difference became smaller. Mechanization of farming works may be partly accountable for the decrease in the regional difference.

Studies on protein nutrition of Papua New Guinea highlanders: nitrogen balance and hematological studies

Studies were made in August 1978 on the N-balance and hematological characteristics of 18 men living in the village of Kalugaluvi (altitude: 1,500m) near Lufa, which is 60km from Goroka, in the Eastern Highland Province of Papua New Guinea. The average daily protein intake on 3 consecutive days was 95.2 +/- 29.3 mgN/kg (35.2 +/- 10.7 g protein/day), and 32.6 +/- 18.7% of the total protein intake was in the form of animal proteins. The calculated nutritional value of the dietary protein, scored according to the 1973 FAO/WHO pattern, was 83.7 +/- 10.6. Urinary and fecal N excretions during the same period were 81.9 +/- 18.7 and 26.3 +/- 11.8 mgN/kg, respectively, giving a nitrogen balance of -13.5 +/- 24.9 mgN/kg. From N-balance data on individuals, the N-intake for maintenance of a zero N-balance was estimated as 116.3 +/- 48.6 mgN/kg (mean 95% confidence interval). Hematological data showed normal or rather high values for hemoglobin (16.90 +/- 1.05 g/100 ml) and serum proteins (8.05 +/- 0.40 g/100 ml). The increased level of serum proteins was associated with an increased globulin level.

Risk factors for cerebral hemorrhage and cerebral infarction in a Japanese rural community

A ten-year follow-up study of stroke among residents 40 years and older in a rural community located on Shikoku Island, Japan, was completed in 1977. The response rate for the initial examinations was 85% of 920 males and 90% of 1,012 females. Seven hundred and seventy-two males and 901 females who were initially free of stroke were followed from July 1967 through June 1977. The incidence of all strokes was 10.47 per thousand person-years for males and 6.41 per thousand person-years for females. The statistically significant risk factors for stroke were age, male sex, elevated blood pressure, ECG abnormalities, and funduscopic abnormalities. Elevated blood pressure was the strongest risk factor and mean arterial pressure was the best predictive measure. Twice as high a proportion of strokes were subclassified as cerebral hemorrhage (26%) in this study as have been reported in comparable studies in the United States (12-15%). An inverse relationship between serum cholesterol levels and cerebral hemorrhage incidence, but not cerebral infarct, was observed. High alcohol intake was a risk factor for cerebral hemorrhage but not for cerebral infarct. No relationship between stroke and weight was observed despite the relationship of stroke to blood pressure and of weight to blood pressure.

Incidence of stroke in Shibata, Japan: 1976-1978

A stroke registry was established in Shibata City, Niigata Prefecture, Japan (population 75,000) in 1976. WHO recommendations for criteria were followed. This paper reports stroke incidence for the initial 3 years of the registry: 1976 through 1978. All living patients were examined clinically by a staff physician. Only patients with a diagnosis of first stroke were included in the study. Sensitivity of the referral system was estimated at 85 + %, comparable to that in American studies. Average annual incidence per 1,000 in resident greater than or equal to 20 years was 2.61 for all strokes (3.42 for males; 1.88 for females), 0.20 for subarachnoid hemorrhage, 0.61 for cerebral hemorrhage, 1.51 for cerebral infarction - rates similar to those reported 10-20 years previously for the United States. The male-female ratio, 2:1, reflected a high rate among males, low among females. Rats among Shibata males were higher than 1972 U.S. rates reported by the Epidemiologic Study Group; rates among Shibata females were lower than corresponding U.S. rates. Incidence of all strokes combined increased with age, the age relationship being strongest for cerebral infarction. No subarachnoid hemorrhage was observed in Shibata residents greater than or equal to 70 years of age.

Nutritional status of Papua New Guinea highlanders

A nutritional survey was held in August, 1978, at Kalugaluvi (altitude: 1,500m) near Lufa, which is 60 km from Goroka, in the Eastern Highland Province of Papua New Guinea. Anthropometric measurements were carried out on 55 males and 37 females aged from 7 to 64 years. whereas the physiques of the children looked as good as those of Japanese of a comparable age, the adult men were shorter than Japanese males, but body weight and chest girth were similar. The skinfold thickness was less than that of the Japanese. From the data collected, it was shown that the physique of the Highlanders was more muscular than that of the Japanese. The food intakes and energy balances of 18 healthy men (20-40 years old) were measured over 2 or 3 consecutive days. The average consumption of sweet potatoes, the staple food, was 956 +/- 305 g per day. The average consumption of taro and yam was 93 +/- 124 g/day and 36 +/- 99 g/day, respectively. Various green leaves, sugar canes, corn, bananas and other foods. (i.e., rice and tinned fish) purchased from trade stores were sometimes eaten. The mean daily energy intake was 2.390 +/- 540 kcal, which was about the same as the daily energy expenditure. The daily protein intake was 35.2 +/- 10.7 g. These results are probably exceptionally high, because the survey was unfortunately held during the yearly festival season of the village when the people often ate fatty port. Nevertheless, it is noteworthy that the growth of children and the physique of adults are normal in spite of the extremely low intake of protein.