The high-risk and population strategy for occupational health promotion (HIPOP-OHP) study: study design and cardiovascular risk factors at the baseline survey.

In order to establish the methodology of a population strategy for improving cardiovascular risk factors, we have planned the High-risk and Population Strategy for Occupational Health Promotion Study (HIPOP-OHP study). This study is a nonrandomized control trial in approximately 6500 participants in six intervention and six control companies. Our population strategy is based on three factors, nutrition, physical activity, and smoking. For each factor, a researcher's working team was organized and has been supporting the intervention. A standardized method to obtain comparable data has also been established. In the baseline survey, urinary sodium excretion in male subjects was higher, and urinary potassium excretion was lower in both genders in the intervention group compared to the control group. The prevalence of hypertension for both genders was also higher in the intervention group. Male subjects in the intervention group had higher serum total cholesterol than controls, while high-density lipoprotein cholesterol was lower in both genders in the intervention group compared to the control group. These differences were reflected by our finding that the predicted relative risk of coronary heart disease for male subjects was significantly higher in the intervention group (relative risk, RR: 1.17; 95% confidence interval, 95% CI.: 1.09, 1.25) and significantly lower in the control group (RR: 0.93; 95% CI.: 0.89, 0.98) compared to a model Japanese population. Similar results were observed in the female subjects. Taken together, these findings indicate that it is possible to compare trends of predicted relative risk for coronary heart disease between two groups.

Health policy in transition: terminal care and site of death in Japan.

OBJECTIVES: In Japan, hospitals have replaced homes as the predominant site of death, especially for the elderly. Site of death is a reliable indicator of where older people receive care before they die. We conducted a population-based study to identify the factors that determine site of death in a typical rural area in Japan. METHODS: Study subjects were residents of Kawakami town, aged 70 years or older, who died during 1981 and 1990. Death certificates provided information on age, gender, cause of death, duration of illness before death, family members, family occupation, and site of death. RESULTS: Among 455 subjects, 52.7% died at home, while 47.3% died in hospital. Multiple logistic regression analyses indicated that subjects with cancer were 6.1 times more likely to die in hospitals than those with other diseases. Subjects who died in their seventies were 2.3 times more likely to die in hospital than older subjects. Members of non-farming families were 1.7 times more likely to die in hospital than members of farming families. Gender, duration of illness, and the presence of spouse or children in the household were not significantly related to site of death according to multivariate analyses, although trends did exist. CONCLUSION: This case study illustrates the importance of developing geriatric care systems in Japan, utilizing alternatives to hospitals, such as nursing homes and formal home care. This is particularly true for patients with cancer. As the older population rapidly increases in Japan, the need for alternatives in geriatric care grows more critical.

Women's anxiety in old age and long-term care provision for the elderly.

The purpose of this study was to verify the differences in women's anxiety in old age, the expected long-term care provision, and the expected final location for terminal care for the women themselves and for their parents. In addition, we examined factors that related to their anxiety and needs. The subjects were 1,000 women of the Seikatsu Club customer cooperative association in Chiba; 539 responded to our survey. The subjects were more anxious for their parents than for themselves. They more strongly expected long-term care for their parents to be provided by their family than they expected the same for themselves. Although no differences were observed in the expected location for terminal care, most subjects expected their home to be the terminal location. Analysis by the multiple logistic regression model indicated that the following factors were significantly related to the anxiety in old age: age odds ratio [OR = 1.81], employment [OR = 2.25] for women, and planning to live with parents [OR = 2.42], housing conditions [OR = 0.56] for parents. The following factors were significantly related to the expected long-term care provision: age [OR = 2.22] for women, and age [OR = 2.15], living with parents [OR = 3.58], and employment [OR = 2.33] for parents. Age [OR = 2.14] for women, and planning to live with parents [OR = 2.09] for parents were significantly related to the expected final location of terminal care. This survey showed that women expected long-term care for their parents to be provided by their family, while many expected public long-term care services for themselves. This is the biggest difference in women's outlook on long-term care for their parents and for themselves. Multivariate analysis suggested that women aged 40 years or over, who will need long-term care in the future, tended to expect public home care services for themselves. It is virtually certain that the demand for public home care services will increase in the future.

Comparative analysis on the physique and batting records of the players in the National Summer High School Baseball Tournaments before and after the adoption of metal bats.

To clarify the influence of the introduction of metal bats on the physique and batting records of the players in the National Summer High School Baseball Tournaments, a comparative analysis was conducted between height, body weight, body-weight ratio (body weight/height), batting average and home run average of the best four teams' players (n = 493) and those of the other teams' players (n = 4,590) in three periods: the period of the use of wooden bats, that of the use of both wooden and metal bats and that of the use of metal bats. In the period of metal bat use, the mean values of physique of the best four teams' players were significantly larger (P < 0.05) and their average number of home runs was significantly higher than those of the other teams' players (P < 0.01). The only significant differences between the two groups in those indices for each time period were for height in the wood and metal/wood periods. This study demonstrated that the differences between the home run average and physique, including height, body weight and body-weight ratio of the best four teams and the rest of the teams were the greatest after the use of metal bats. These findings suggest that the importance of the home run average increased and was associated with large-size of physique after the use of metal bats in the National Summer High School Baseball Tournaments.

Relation between the instrumental activities of daily living and physical fitness tests in elderly women.

A cross-sectional study was conducted to quantitatively evaluate the relationship between the instrumental activities of daily living (IADL) and various physical fitness tests in elderly women living at home. The study focused on the total population of those women aged 65 years and over living in Y Town, Hyogo Prefecture, Japan, who visited a nursing home for day services. A total of 128 subjects were divided into two groups: dependent in IADL group (n = 49) and independent in IADL group (n = 79). The magnitude of the relation was evaluated by the odds ratio (OR). The following tests showed a significant decrease in IADL: knee-raising test [age-adjusted OR = 4.23, 95% confidence interval (CI) 1.81-9.87], height (age-adjusted OR = 4.09, 95% CI 1.75-9.56), grip strength (age-adjusted OR = 3.68, 95% CI 1.57-8.60), sit-and-reach test (age-adjusted OR = 2.76, 95% CI 1.20-6.34), and standing on one leg with closed eyes (age-adjusted OR = 2.56, 95% CI 1.09-5.97). Multivariate analysis using Hayashi's quantification method I indicated that knee-raising was the test most highly correlated with decreased IADL. These results suggest that measurement of knee-raising ability, muscle strength of the lower extremities and flexibility of hip joint could be the most useful factors to assess the level of instrumental self-support ability.

The relationship between job stress and mental health at work.

In order to evaluate the relationship between job stress and mental health, a cross-sectional study was conducted using a questionnaire relating to demographics, subjective job stress and mental health state. The questionnaire consisted of a 30-item Japanese version of the General Health Questionnaire (GHQ) developed by Goldberg in addition to questions about subjective job stress, to measure mental health and job stress conditions, respectively. All subjects were employees of an electronic company in Japan. Among 782 workers, 763 workers responded to the questionnaire satisfactorily (response rate was 97.6%). People whose GHQ score was more than 7 were classified as having psychiatric problems, while the remaining respondents were considered as having no mental health problems. We employed a multiple logistic regression analysis to estimate the relationship between subjective job stress and mental health, adjusting for gender, age, marital state, familial stress, and physical health state. Subjective job stress was significantly associated with the state of mental health. In particular, the items of "too much trouble at work," "too much responsibility," "are not allowed to make mistakes," "poor relationship with superiors," and "cannot keep up with technology" were significantly related to mental health.

[The impact of partial cost sharing on the attitude of insured persons with hypertension].

The study evaluated the impact of the October 1984 introduction of 10% cost sharing on insured persons belonging to the Employees' Health Insurance Scheme. There was a total of 199 subjects with hypertension, all of whom were insured by a health insurance society under the scheme from January 1982 to March 1986. The consultation rate for hypertension, as revealed by the medical receipts, was studied with time sequential analysis to evaluate the impact. Moreover, the differences of the impact pertinent to sex, age, medical facility, first year of visit and complications were analyzed. The results are as follows. 1. The study disclosed an increase in the rate of consultation during the six-month period before the introduction and a substantial decrease in the rate during the following six months. The impact proved to be temporary because the rate of consultation returned to the originally estimated level. 2. The impact on insured persons whose first year of visit was more recent was larger than that of those whose first year of visit was before 1980. The impact on patients with complications was larger than that on those without complications. 3. The effect of the first year of visit was independent of that of complications.

[The US Health Care and the reform].

Securing access to medical services, controlling costs and improving quality are goals of health care system. Although they are all the same all over the country, each country has its own culture, health care system and health care problems. In the United States, employer-based and individual purchases of private health insurance coverage play a major role, although governmental programs such as Medicaid and Medicare exist for the poor and the elderly. Private health insurance had traditionally secured patients' freedom of choice of health care providers and physicians' professional freedom and had paid providers on a fee-for-service basis. Now, the U.S. has 40 million uninsured persons who do not have access to medical services, although it spends as much as its 14% of GNP on health care. In the early 1990s, this became a major political problem. President Clinton proposed the 'Health Security Act' which would enable any American to have access to comprehensive health care with managed competition to activate the health care market, but it was not enacted. Nevertheless, it is clear that managed care and managed competition will dominate and that traditional fee-for-service plan will be eroded in the health care market. Japan has a universal health care system. We do not have any uninsured or high medical costs. However, it is difficult to improve the quality of health care services within the present system. Japan can learn the system about disclosure of health care information from the managed care in the U.S.

[Effect of physical activity on physical fitness among workers].

We conducted a cross-sectional study to clarify the effects of physical activity on physical fitness. Physical fitness tests were offered to workers of companies manufacturing automobile parts from December, 1992 to December, 1993. The subjects were 1,217 male and 600 female workers who participated in the physical fitness test. From this group, we analyzed 1,048 male and 522 female workers who answered a physical activity questionnaire. The questionnaire included age, sex, working posture, physical activity during working time and physical activity during leisure time. The physical fitness tests were composed of grip strength, standing trunk flexion, foot balance with closed eyes, jumping reaction time and step tests. We classified the subjects into low performance group and high performance group for each test. In addition, we classified the subjects into different groups by age (16-29 years old, 30-49 years old old and 50-69 years old), by working posture (standing and sitting), as well as by activity levels during working time and leisure time physical activities (inactive and active). Thus, we examined potential risk factors for the physical fitness by a multiple logistic regression model. The results were as follows: 1. Standing work was a significant risk factor for grip strength, foot balance with closed eyes and jumping reaction time in male workers, and standing trunk flexion, foot balance with closed eyes, jumping reaction time and the step test in female workers. 2. Physical activity during working time was not related to physical fitness in male and female workers. 3. Inactivity during leisure time was a significant risk factor for standing trunk flexion, foot balance with closed eyes, jumping reaction time and the step test in male workers, and grip strength and foot balance with closed eyes in female workers. 4. Young age (16-29 years old) was a significant risk factor for grip strength, standing trunk flexion, foot balance with closed eyes, jumping reaction time and the step test in male and female workers. Middle age (30-49 years old) was a significant risk factor for foot balance with closed eyes and jumping reaction time in male workers, and standing trunk flexion, foot balance with closed eyes, jumping reaction time and the step test in female workers.

[Causal inference in medicine--a historical view in epidemiology].

Changes of causal inference concepts in medicine, especially those having to do with chronic diseases, were reviewed. The review is divided into five sections. First, several articles on the increased academic acceptance of observational research are cited. Second, the definitions of confounder and effect modifier concepts are explained. Third, the debate over the so-called "criteria for causal inference" was discussed. Many articles have pointed out various problems related to the lack of logical bases for standard criteria, however, such criteria continue to be misapplied in Japan. Fourth, the Popperian and verificationist concepts of causal inference are summarized. Lastly, a recent controversy on meta-analysis is explained. Causal inference plays an important role in epidemiologic theory and medicine. However, because this concept has not been well-introduced in Japan, there has been much misuse of the concept, especially when used for conventional criteria.

[The effect of sharing medical costs for the aged 70 or more on the financial balance of the health insurance society].

The rapid increase of the proportion of older persons in society has made the problem of medical costs more important. Although medical cost-sharing for those aged 70 or more is decided by their medical costs and by the current proportion of such persons in the Society, it is not constant throughout the Society. The study evaluated the contribution ratio of medical cost-sharing for those aged 70 or more to the financial balance of the Society. In addition, characteristics of the Society associated with medical cost-sharing for those aged 70 or more were analyzed. The results are as follows. 1) Medical cost-sharing for those aged 70 or more was the greatest factor in the financial balance of the Society with a contribution ratio of as much as 55.2%. 2) Multiple regression analysis disclosed that dependent ratio, the average monthly salary, the area, the rate of those aged 70 or more and the average age of the Society members are significant in medical cost-sharing for those aged 70 or more. 3) Dependent ratio and the average monthly salary are the most important characteristics among those associated with medical cost-sharing for those aged 70 or more. A higher dependent ratio and a lower average monthly salary are related to higher cost-sharing. This is also related to geographic factors as cost-sharing in western Japan is higher than in eastern Japan. The lower rate of those aged 70 or more and the higher average age of the Society members are related to the higher cost-sharing.

[Achievement of causal inference in the social medicine in Japan].

As a condition to achieving an agreement of recognition on the causal relationship in medicine, we firstly explained Hume's problem and counterfactual model. We, however, emphasized that we believe in the existence of causality on medical issues in our daily lives. Therefore, we illustrated conditions when we usually believe in causality. On the other hand, we criticized two well-known key phrases, "lack of mechanism in epidemiology" and "black box in epidemiology", which have often been used in Japan for skeptic viewpoints against epidemiologic methods even if epidemiology is often used to elucidate a causal effect in medicine in the world. We emphasized that a priori determinations of levels for inference of mechanism is necessary. And, the level and feature of mechanism should be defined in concrete expressions. After explanation of these basic concepts, we mentioned a classic view on specific diseases and non-specific diseases which have not been sufficiently discussed enough yet in Japan. As an example, we used the statements in the Japanese Compensation Law for the Health Effect by Environmental Pollution. In Japan, the classification of these diseases has been confused with that between manifestational criteria of diseases and causal criteria of them. We described the basic concepts to illustrate the causal relationship between non-specific disease and its exposure by using attached figures. Actually, we cannot recognize disease occurrence as a specific disease for several reasons. We indicated that we can recognize the magnitude of effect by causal relationships in medicine as a quantitative continuous variable.

[An epidemiologic research design using the Annual of the Pathological Autopsy Cases in Japan].

Epidemiologic research designs using the Annual of the Pathological Autopsy Cases in Japan (APAC hereinafter) are discussed in this paper. The APAC data base has been recommended for use in epidemiologic research. However, it has not often been utilized for such research, even though it covers all pathological autopsy cases in Japan, perhaps because of different sampling proportions of each disease and because of the dead control series in APAC. First, we present epidemiologic measures in using the APAC. We show that the data base can be treated as a case-control design and that the magnitude of the exposure effect should be estimated by an odds ratio. Next, selection bias and information bias in using the APAC are discussed. The independence of the control series from the exposure is important in the determination of the control disease. Because this design is based on internal comparison, non-differential misclassification should be stressed more than differential misclassification.

[Causal inference in medicine: a reaction to the report, "incidence of Minamata disease in communities along the Agano River, Niigata, Japan--patterns of the exposure and official diagnosis of patients"].

Kondo's "Incidence of Minamata Disease in Communities along the Agano River, Niigata, Japan (Jap. J. Hyg. 51:599-611;1996)" is critically reviewed. The data of the article were obtained from most of the residents living in the Agano river villages where Minamata disease was discovered in June, 1965. However, sampling proportions were much different between in the population base and in the cases. The method of identification of cases from the data and the reason for the difference were not clearly demonstrated. The citations of reference articles are insufficient despite the fact that other epidemiologic studies on methyl-mercury poisoning have been reported not only in Japan, but also around the world. His "analysis of the recognized patients" is erroneous. Both the sampling scheme of information of hair mercury and the modeling of the analysis are based on Kondo's arbitrary interpretation, not on epidemiologic theory. His "analysis of the rejected applicants" is also erroneous. His calculations of the attributable proportion are incorrect and self-induced in both the assignments of data and analysis of data. Kondo has failed to study the epidemiologic theories in light of changes in the field. Therefore, his article is lacking in epidemiologic theory, a logical base and scientific inference. In Japan, epidemiologic methodology has rarely been used in studies on Minamata Disease in either Kumamoto and Niigata. The government has used neurologically specific diagnosis based on combinations of symptoms to judge the causality between each of symptoms and methyl-mercury poisoning. Epidemiologic data obtained in Minamata, Kumamoto in 1971 indicate that the criteria set by the government in 1977 have produced much more false-negative patients than false-positive patients. As a result, a huge number of symptomatic patients, including those with peripheral neuropathy or with constriction of the visual field, did not receive any help or compensation until 1995. The authors emphasize that the causal relationship between each symptom and methyl-mercury exposure should be reevaluated epidemiologically in Japan.

[Family intervention for schizophrenia based on expressed emotion (EE) research: a review of the technique and evaluation].

The present study reviews eight series of trials on psycho-social family intervention for schizophrenia based on Expressed Emotion (EE). All studies used randomized controlled trials (RCT) except one which was non-randomized controlled trial. The relapse risk ratios (intervention/control) for 9-12 months after discharge were 0 to .73 and for 24 months were .20 to .57. Taking into account the shortcomings of the studies, the authors conclude that psycho-social family intervention based on EE is effective in preventing schizophrenic relapse, and discuss four important issues: 1) For effective family intervention, methods for Japanese patients should be established from a trans-cultural view point; 2) The interaction of two or more therapeutic measures should be evaluated quantitatively; 3) The mechanisms of schizophrenic relapse prevention through family psycho-social intervention should be explored. A psycho-physiological study including skin conductance measurement is promising; 4) The authors point out the ethical aspect of family intervention, and discuss the importance of informed consent and the need to place emphasis on family's needs.

[Causal inference in medicine--decision making].

In the field of occupational medicine, either when we consider some preventive plans or when we make decisions to compensate for occupational diseases, it has been necessary to discuss causality between work and disease. Furthermore, epidemiologic causality has recently been used in risk assessment in occupational and environmental settings. We have shown that the law of causality in medicine is recognized as probability and continuous variables. Such a law of causality has been recognized in the same way as probability in physics, too, and has been regarded as a model of science. Physicists and mathematicians had claimed the importance of probability in causal inference as well as the principle of uncertainty before it was discovered. We, then, explained Etiologic Fraction (EF), Attributable Proportion for the Exposed Population (APE), Probability of Causation (PC), and so on. The PC has been used to ascertain the conditional probability in an individual case of a disease having been caused by a particular prior exposure, by using the experience of exposed populations to determine the appropriate relative risk, and this has been used for compensation for exposed cases. Next the applicability of information from a population to individuals was presented. Third, we provided a brief historical aspect of epidemiology. The evolutions in Epidemiology have been very rapid, so we pointed out that, in Japan, we could observe many incommensurable phenomena in epidemiologists and physicians depending on the era which was studied by them. Fourth, we discussed judgement and political application based on epidemiologic evidence, using Yanagimoto's classification is also taken or not should be estimated and compared. We presented several examples of reasoning in judgements. Lastly, we discussed several tasks and assignments for the future of epidemiology.

A comparison of international health outcomes and health care spending.

Does increased spending improve health outcomes? We analyzed 1988 data from OECD countries to determine how key health care indexes correlate with health care outcomes. Total health care spending per capita and outpatient and inpatient utilization are not related to health outcomes. How our resources are allocated seems to be more important than how much money is actually spent.

Declining cost-effectiveness of screening for disease. The case of gastric cancer in Japan.

We examined the cost-effectiveness of screening for gastric cancer in hypothetical cohorts of asymptomatic Japanese ages 40, 50, 60, and 70, followed for 10 years. Current screening recommendations in Japan are not optimal. Although indirect x-ray is the correct method, screening for gastric cancer may not be cost-effective for Japanese under the age of 50. Policymakers worldwide should monitor the changing incidence of disease as they consider and recommend screening policies.

The effect of a cost sharing provision in Japan.

This study evaluated the effect of a 10% cost sharing provision, introduced in October 1984, on demand for medical services. We analysed the data of 1701 health insurance societies, all of which joined the National Federation of Health Insurance Societies between 1983 and 1985. The case rate (per 1000 persons) and the number of serviced days (per case) were analysed as indicators of demand for inpatient, outpatient and dental medical services. The case rate was considered to be an indicator of the patient's behaviour, while the number of serviced days was influenced by the doctor's behaviour. Multiple linear regression analysis was used with each indicator to isolate the effect of the cost sharing provision, adjusted for other variables which influenced demand for medical services. The case rate was reduced significantly in all medical services. This means that a patient was discouraged from using a medical facility by the cost sharing provision. There was little difference among medical services. The number of serviced days was also reduced significantly in all medical services. There was a large difference among medical services. The effect on outpatient service was much greater than that on any other service.