Stages of Change for Salt Intake and Urinary Salt Excretion: Baseline Results from the High-Risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study

We investigate the relationship of urinary salt excretion to the stage of change to decrease salt intake in the Japanese diet. The data reported here were obtained from a baseline survey of the High-Risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) study that was conducted as a non-randomized control trial at 12 worksites in Japan. A total of 6,816 subjects (5,410 male, 1,406 female) were used in 1999 and 2000 for the analysis. We used three categories of stage of change: precontemplation or contemplation (P/C), preparation (P), and action or maintenance (A/M). Urinary salt excretion was estimated from the sodium and creatinine concentrations in spot urine samples. Multivariate analysis indicated that urinary salt excretion among males was 0.3 g/day greater in the P/C stage than in the A/M stage (p < 0.05). For non-obese females, urinary salt excretion in the P/C stage was 0.6 g/day greater than in the A/M stage (p < 0.05). Multivariate analysis showed that diastolic blood pressure in males not taking antihypertensive agents was 1.3 mmHg lower in the P/C stage than in the A/M stage (p < 0.05). A similar but statistically insignificant tendency was observed among non-obese females. A significant association was demonstrated between stage of change for dietary salt intake and urinary salt excretion for both males and non-obese females. There may be a potential application of the stage of change model for reducing dietary salt intake in a health promotion program.

[Relationship of childhood obesity to adult obesity: a 20-year longitudinal study from birth in Ishikawa Prefecture, Japan]

OBJECTIVE

Evidence regarding the relationship between childhood obesity and adult obesity in Japan is limited. This study was conducted to determine the relationship between childhood mass index (BMI) at 3 months, 12 months, 3 years and 20 years in a general population.

METHODS

Data obtained from men and women aged 20 years (born between 1968-1974), who had received medical examinations in Ishikawa Prefecture, Japan, were linked to data of medical examinations of the same individuals as infants (3 months, 12 months, and 3 years). The relationship between childhood BMI (or Kaup index) and adult BMI was analyzed for a total of 2,314 participants (1,080 men and 1,234 women), whose data could be followed for 20 years.

RESULTS

BMI at 20 years displayed significant positive correlations with BMI at 3 months, 12 months, and 3 years; this correlation was strongest with respect to BMI at 3 years (r = 0.33, p < 0.001 in men; r = 0.42, p < 0.001 in women). In terms of percentages of obese participants (BMI 25 kg/m2 or over) at 20 years in accordance with BMI categories at each age, the rates were 4.6% in men and 1.0% in women with a BMI less than 15 kg/m2 at 3 years, but 29.1% and 29.5%, respectively, with a BMI of 18 kg/m2 or over (6.3 and 29.5 times higher, respectively). Percentages of obese participants at 20 years were highest in those exhibiting an above average BMI at 3 years, regardless of the BMI at 3 months.

CONCLUSIONS

Body mass in young adults is strongly related to body mass in childhood, especially with that at 3 years. About 30 percent of obese children at 3 years remain obese into adulthood. These results are of interest with respect to assessment of future risk of adulthood obesity at medical examinations for infants in Japan.

[[Comparison of mortality rates of elderly people in China and Japan]]

"The mortality rates and causes of death among elderly people aged sixty five and over were compared between China and Japan. The data used for comparison was China's 1990 and Japan's 1990 vital statistics. It appears that the mortality rate in China was higher than Japan. Comparing the causes of death, it was found that the death rates involving cerebrovascular diseases, malignant neoplasms and heart diseases in urban districts of China [were] higher than those in Japan. Also the death rate of people with bronchitis in rural districts was significantly higher in China.... The differences in the medical systems and life styles in China and Japan were suspected as the reasons for the differences of death rates and causes of death...." (SUMMARY IN ENG)

A cross-sectional study on association of calcium intake with blood pressure in Japanese population

To investigate the association of calcium intake independently of other nutrients already known as predictors of hypertension, a cross-sectional study was carried out on the same population in Japan as used for the INTERSALT study. Dietary calcium intake was estimated from a 1-day 24-h recall. Sodium and potassium intakes were evaluated by 24-h urinary excretion. Data from 476 subjects aged 20-59 years, 230 men and 246 women, were analysed. The mean dietary calcium intake ranged from 557 to 608 mg/day among men, and from 528 to 639 mg/day among women. Among men, the pooled estimate of the regression coefficients of blood pressure (mm Hg) per 100 mg increase of calcium intake, adjusted for age and body mass index (BMI), were -0.42 mm Hg for systolic blood pressure (SBP) and -0.35 mm Hg for diastolic blood pressure (DBP), but there was no statistical significance. Among women, the pooled estimates of regression coefficients adjusted for age and BMI were -0.92 mm Hg for SBP and -0.83 mm Hg for DBP with statistical significance. After adjustment for age, BMI, alcohol intake and urinary excretion of sodium and potassium, the pooled estimate of calcium intake was -0.66 mm Hg for DBP with statistical significance and -0.70 mm Hg for SBP. A significant negative association of calcium intake with blood pressure was observed among the subjects in Osaka. Our study suggests that increased calcium intake may provide a benefit of lowering blood pressure independently of other minerals such as sodium and potassium.

Trends in stroke incidence and acute case fatality in a Japanese rural area : the Oyabe study

BACKGROUND AND PURPOSE

Stroke mortality in Japan has significantly declined during recent decades. To determine the cause of this decrease, we studied the trends in stroke incidence and case fatality within 28 days after stroke in a rural area in Japan.

METHODS

We used a population-based registry during 1977-1991 in Oyabe, a rural area in the central part of Japan. The average population aged 25 years and older numbered 32 859 persons. Changes in age-standardized stroke incidence rate were calculated and compared between the 3 periods 1977-1981, 1982-1986, and 1987-1991. The 28-day case fatality rate was evaluated and also compared between the 3 periods by onset year.

RESULTS

The total number of strokes was 2068. The age-standardized incidence rate of all strokes decreased during the 15-year period, from 605 to 417 per 100 000 in men and from 476 to 329 per 100 000 in women. A marked decline was found during 1977-1986 but was not apparent during 1987-1991. Moreover, there was an increase in the group aged 75 years and older. The 28-day case fatality rates for all strokes improved from 18.0% to 14.2% in men and from 26.8% to 19.1% in women during the observation period.

CONCLUSIONS

These data indicate that declines in the stroke incidence and the 28- day case fatality have been associated with a marked decrease in stroke-related mortality in Japan.

Relationship between urinary cadmium and mortality among inhabitants living in a cadmium polluted area in Japan

A 15 year follow-up study of 3119 inhabitants living in a cadmium polluted area was conducted to investigate the influence of environmental cadmium exposure on the mortality. The cumulative survival curves of the subjects with urinary cadmium concentration > or = 10 microg/g creatinine was lower than that of the subjects with < 10 microg/g creatinine in the men aged 50-59 and 60-69 years and in the women aged 60-69 and 70-79 years. In the men aged 50-69 years and the all aged women, the cumulative survival curves became lower in proportion to the increase of urinary cadmium concentration, when the subjects were divided into four groups according to the amount of urinary cadmium concentration (< 5, 5-9.9, 10.1-19.9, > or = 20 microg/g creatinine). These results suggested a dose response relationship between cadmium exposure and mortality.

Relationship between shift work and onset of hypertension in a cohort of manual workers

OBJECTIVES

This study investigated the possibility of a relationship between blood pressure level and rotating 3-shift work in a prospective follow-up of workers in a zipper and aluminum sash factory in Japan.

METHODS

Altogether 1551 men aged 18-49 years were followed prospectively for 5 years, and the cumulative incidence of hypertension among 3-shift workers was compared with that of day workers. A multiple logistic analysis was used for adjusting for base-line characteristics such as age, body mass index, blood pressure, and drinking habit.

RESULTS

In the younger age group, the relative risk of the rotating 3-shift workers during the observational period was increased compared with that of day workers after adjustment for the confounding factors. In the older group, the cumulative incidence of hypertension was not higher for workers who had continued shift work. However, a relatively high risk of hypertension was found for workers who converted from 3-shift work to day work when compared with those who remained on shift work and day work.

CONCLUSIONS

It is suggested that there is an association between 3-shift work and blood pressure.

[The development of the Japanese version of the Maslach Burnout Inventory and the examination of the factor structure]

This article presents an evaluation of the factor structures of the Japanese version of the Maslach Burnout Inventory (MBI). The MBI is a widely used psychometric instrument for measuring 'burnout' developed by Maslach and her co-workers. The MBI consists of four subscales: Emotional Exhaustion, Personal Accomplishment, Depersonalization, and Involvement. The MBI was translated into Japanese along with a back-translation and was administered to a sample of 267 nurses. Various psychometric analyses showed that the Japanese version of the MBI has high reliability for the 22 items scored for the frequency dimension. The factor analysis using principal factoring with an oblique rotation resulted in three factor structures that had different implications from the MBI: Emotional Exhaustion/Depersonalization, Personal Accomplishment, and Physical Exhaustion. The correlationship between the MBI and the General Health Questionnaire (GHQ), measures of depression, showed that burnout was a unique phenomenon.

Blood pressure and urinary C-peptide excretion in subjects with varying degrees of glucose tolerance

To determine whether blood pressure is associated with 24-h urinary C-peptide excretion in subjects with varying degrees of glucose tolerance, we studied 247 Japanese men aged 30-69 who had never been treated with antihypertensive medications or with insulin. Plasma glucose and insulin responses during a 75-g oral glucose tolerance test, blood pressure and body mass index were obtained and urinary C-peptide excretion, in total and per kg body weight, were examined by 24-h urine collection. In monovariate analyses, urinary C-peptide excretion per kg body weight increased significantly as the blood pressure level rose (p < 0.05). After adjustment for age and body mass index by analysis of covariance, this relationship remained significant (p < 0.05), where adjusted mean values (+/- SEM) of urinary C-peptide per kg body weight were 1.56 +/- 0.05 microgram/24h/kg in the normotensive group and 2.04 +/- 0.17 microgram/24h/kg in the hypertensive (stage 2-4) group. When stratified simultaneously by glucose tolerance status and blood pressure level, adjusted mean values of urinary C-peptide per kg body weight were significantly higher in diabetic hypertensives than in diabetic normotensives. These results suggest that increase in 24-h urinary C-peptide excretion, i.e. 24-h insulin secretion, might contribute to an elevation of blood pressure both in normal and diabetic individuals.

Plasma insulin and blood pressure in normotensive Japanese men with normal glucose tolerance

OBJECTIVE

To determine whether blood pressure within the normal range is associated with plasma insulin concentration in a Japanese population with normal glucose tolerance.

METHODS

We studied 491 normotensive Japanese men with normal glucose tolerance, who had never been treated with antihypertensive medications. Plasma glucose and insulin response during a 75-g oral glucose-tolerance test, blood pressure, body mass index, serum lipids, alcohol consumption and smoking status were obtained. The subjects were divided into quartiles according to mean blood pressure level (< 79, 79-84, 85-91 and > or = 92 mmHg). To eliminate possible confounding factors, analysis of covariance was also performed.

RESULTS

In univariate analyses the plasma insulin response after an oral glucose load, especially after 60 min, was significantly related to blood pressure level. Plasma glucose was related to blood pressure level only at fasting. When adjusted for age, body mass index, plasma glucose response and alcohol consumption, plasma insulin concentrations after 30 and 60 min in the highest quartile were significantly higher than those in the lowest quartile.

CONCLUSIONS

Blood pressure was significantly and independently related to plasma insulin level after an oral glucose load in normotensive Japanese men with normal glucose tolerance. The results suggest that the relationship between blood pressure and insulin resistance already exists in a prehypertensive state even in a lean Asian population.

Comparative study on mortality patterns in Japan and China

On the basis of the 1990 Chinese death notice data and 1990 Japanese populations vital statistical materials, the mortality patterns and proportions of individual causes of death in the two countries were compared. In both sexes, the mortality rates were the highest in almost all age groups in Chinese rural areas followed by urban areas and Japan. In Japan and in Chinese urban areas, malignant neoplasms cardiovascular diseases and cerebrovascular diseases were the major causes of death, with these three making up about 60% of the total. In Chinese rural areas, these three conditions were responsible for 43% of all deaths, a considerably lower figure as compared to those in the other two areas, and the mortality rates for infectious diseases and accident/suicide were higher than those in the other two areas. Of the three major adult diseases, cerebrovascular diseases were found to be especially frequent in both Chinese urban and rural areas. On the other hand, ischemic heart disease was found at comparable levels in Japan and China and the rate was lower than in other developed countries. Site-specific mortality rates for malignant neoplasms were characterized by high rates for lung, liver and esophageal cancers in China. The mortality rates for bronchitis in both Chinese urban and rural areas were markedly higher than those in Japan These differences in mortality rates and proportions of individual causes of death between China and Japan are thought to be attributable to the differences in medical services and the level of risk factors for each disease.

Potassium/energy and phosphorus/calcium ratios reflect the quality of nutrition

A nutritional survey and questionnaire regarding dietary habits were administered to 649 men ranging in age from 35 to 64 years receiving a one-day health screening examination. First, comparisons of nutrient intake based on the nutrient rate of the Recommended Dietary Allowances for Japanese (RDA), and the total score on the questionnaire regarding dietary habits according to the RDA rates of total energy and calcium (Ca) were investigated. Then, the comparisons of intake of food groups, intake of nutrients and the total score on the questionnaire regarding dietary habits according to potassium/energy (K/E) ratio and phosphorus/calcium (P/Ca) ratio were determined. Last, differences between comparisons with the nutrient rates of RDA and comparisons with K/E ratio and P/Ca ratio were investigated. The following results were obtained: 1. Even in the group with RDA rates of total energy or Ca of > or = 90% and < or = 110% the RDA rates of some other nutrients were out-side the appropriate range. 2. In the group with high K/E ratios, as compared to the group with low ratios, the intake of potatoes, pulses, fruits, green/yellow vegetables, other vegetables, soy sauce, other beverages, fish/shellfish, and milk products showed high values, while cereals and fats/oils showed low values. For this reason, in the former group as compared to the latter, the intake and RDA total energy rate showed low values whereas the intake and RDA rates of nutrients such as Ca, Fe, and vitamin A were low. 3. In the group with high P/Ca ratios, as compared to the group with low ratios, the intake of beer and meats showed high values while that of pulses, green/yellow vegetables, and milk products showed low values. For this reason, in the former group as compared to the other groups, despite the fact that the intake and RDA total energy rate tended to be higher, the intake of nutrients such as Ca, P, K, and vitamin A showed lower values. 4. The RDA rates of all of the nutrients of group with a high K/E ratio and the group with a low P/Ca ratio generally showed largely appropriate values. 5. These results suggest that indices reflecting the balance of minerals such as the K/E and P/Ca ratios more objectively reflect the quality of nutrition than comparisons based on the RDA rates of total energy and specific-nutrient.