Weak associations showing odds ratios of less than (say) three to one are often due to chance, bias, or confounding; but if they are causal and relate to common diseases and agents that are prevalent in the community they may be important for the public health and more important than strong associations with agents that occur only rarely. Their establishment requires large studies, meta-analysis of many small ones, or, better, collaborative reanalysis of many studies on a common basis. In the absence of experimental evidence, bias and confounding have to be excluded and positive evidence for causality sought using Hill's guidelines. Examples are given of weak associations that have been shown to be of practical importance (stomach cancer and smoking, lung cancer and environmental tobacco smoke, breast cancer and oral contraceptives) or are still of uncertain significance (liver cancer and smoking, and childhood leukaemia and brain cancer and exposure to extremely low frequency electromagnetic fields). Weak associations that reflect causality can often be revealed only by epidemiological investigation. They may be socially important and their establishment is a challenge that epidemiologists should accept. J Epidemiol, 1996 ; 6 : S11-S20.
The development of epidemiology is described with particular emphasis on the role of the founders of the lEA. The purposes of the subject are outlined and comments on recent concerns discussed. The importance of strategic designs and questions in epidemiologic studies are high- lighted with an example from an international study on chronic respiratory disease. Examples are given form recent studies on the need for proper design of a study in order to provide worth while answers for the application of the findings to the development of policy. J Epidemiol, 1996 ; 6 : S21-S28.
Major changes in health of the population are primarely defined by mather and child health rates. A number of negative trends in mother and child health have occured last years in Russia. Two of each five registered marriages are dissolved. Each year 16% of infants are born out of wedlock, and 600, 000 children lose one of their parents. From 1985 to 1991 birth rates declined 1.6 fold. 34.4% of pregnant women suffered of anemia in 1995. Each year 480, 000 women die globally due to complicated pregnancy and delivery. Maternal mortality in Russia is 52.8 per 100, 000. The number of unhealthy newborns and children grows. That is why a number of Russian federal programms on maternal and child health improvement are being implemented from the year 1990. J Epidemiol, 1996 ; 6 : S29-S34.
Reproductive epidemiology is a research field which should be given high priority. The perinatal time period is a time period of high risk and an increasing number of studies indicate that there may be a fetal origin of several diseases which surface to clinical detection in adult life and which have major public health importance. Since the population in the world is still growing, little time and effort has been spent on research in human fecundity. The rising cost of infertility treatment and new findings indicating a possible decline in sperm production have, however, changed the picture and research funds are now allocated to research in the causes of subfecundity. Time has come for ambitious projects in the field. J Epidemiol, 1996 ; 6 : S35-S38.
Observations at ecological level show strong correlation between exogenous exposures, such as fat consumption, and risk of cancers. The correlations are less but significant at an individual level between many dietary items and cancer risk based on case-control and cohort studies. Most specific attempts to evaluate the role of diet on cancer risk stems from use of serum sample banks and estimation of different components of biochemistry in cases of cancer and healthy controls. The extension of this vast amount of epidemiological knowledge has resulted in preventive trials, chemoprevention of cancer, and in routine use of preventive substances, vitamins and minerals. However, the trials are relatively few and even less frequent are those with invasive cancer as end point. Furthermore, the results of these trials have been rather negative, and it seems at present that vitamins and minerals videly used in adult age for chemopreventive purposes are relative ineffective to prevent occurrence of invasive cancer or death from cancer. This does not imply that these chemical substances were not causes of cancer. J Epidemiol, 1996 ; 6 : S39-S42.
Although genes play a role in the pathophysiology of asthma, the genotypic variants that permit the development of asthma are common and lifestyle and environment are the limiting factors determining the prevalence of asthma. There is now strong evidence for a widespread increase in the prevalence of asthma over the last 30 years at least, and evidence is emerging that the prevalence of asthma varies widely between different populations, even in countries that have adopted a "Western lifestyle". Much of this variation is due to variation in the prevalence of sensitization to common allergens, but the causes of this variation are also unclear. There is an excess mortality in those with asthma, predominantly in the older age group. Attempts to improve the management of the disease throught better delivery of services are still largely unevaluated. J Epidemiol, 1996 ; 6 : S43-S47.
Although being one of the most thoroughly studied diseases in epidemiology, tuberculosis (TB) is now re-emerging with quite new epidemiological characteristics, such as TB combined with HIV infection, and multiple-drug resistance TB. These new aspects can add very serious impact on the existing health burden of TB, especially its serious inequality between developed and developing parts of the world in demographic, social and economic terms. These epidemiological aspects of TB problem will be illustrated in a stepwise way, using several mathematical models. The application of epidemetric model of TB is also shown for evaluation of some TB control measures. J Epidemiol, 1996 ; 6 : S57-S63.
New emphasis is placed in preventive cardiology on the concept of prevention of cardiovascular (CVD) risk factors in the first place: Success would make the risk factors themselves rare in the population, and even early pre-adult atherosclerosis would become less common and less extensive. This concept raises several practical considerations which will be illustrated by selected data. (1) Risk factor prevention includes "primordial prevention, " conceived by Strasser; but where primordial prevention is too little or too late (the usual case?), prevention of the risk factors must address the already-affected population. (2) Risk factor prevention includes an important focus on youth but must extend to both earlier and later ages to achieve its goals; this is because, on the one hand, the risk factors and atherosclerosis may be advanced already during youth and, on the other hand, risk factor development progresses well beyond youth. (3) Risk factor prevention requires that several socially institutionalized gaps be bridged --- such as those between childhood and adulthood, school and workplace, or pediatrics and adult medicine; continuity of preventive policies and practices is needed instead. (4) Risk factor prevention depends on better understanding of the determinants and early development of the risk factors; causal relations between preconditions for risk factor development and progression of the risk factors themselves need to be firmly established, just as the risk factors have long since become strongly linked to CVD events. (5) Risk factor prevention should be measured by reductions achieved in rates of progression of the risk factors, in either their absolute levels or rates of change with age, or in the frequency with which they reach levels requiring treatment. (6) Risk factor prevention requires further research through both observational studies and intervention trials, to be followed by long-term demonstrations to evaluate the effectiveness and costs of intervention. J Epidemiol, 1996; 6: S65-S69.
The present paper addresses functional capacity as a reasonable proxy for health in the elderly. The conceptual framework and its relation to quality of life and productivity are stated. Distributions of functional capacity according to a scale from low to high levels of functioning are shown. Cross-cultural differences, regional differences, and predictors of functional capacity and active life expectancy are also described. J Epidemiol, 1996; 6: S71-S78.
Behavioral Medicine has been defined as the interdisciplinary field concerned with the development and integration of psychosocial, behavioral and biomedical knowledge relevant to health and illness, and application of this knowledge to prevention, etiology, diagnosis, treatment and rehabilitation (International Society of Behavioral Medicine, 1990). Behavioral Medicine is a relatively new field with the scope extending from the research efforts to understand fundamental biobehavioral mechanisms to clinical diagnosis, treatment, disease prevention and health promotion. In this report, our own past studies based on biobehavioral and epidemiological approach in occupational, environmental and community health were summarized. The topics were morbidity, mortality and longevity of Japanese population (i.e., peptic ulcer in factory workers, mortality of medical practitioners and of working and nonworking population, and longevity of total Japanese population), suicide mortality (seasonal and secular trends and social life factors), traffic accident (accident-prone drivers and social risk factors), mass psychogenic systemic illness, and work stress (technostress and sociobehavioral, physical and mental effects). J Epidemiol, 1996 ; 6 : S79-S88.
Methods: Needs for services for people with ischaemic heart disease were assessed for two defined county populations. Current clinical, epidemiological and health services research evidence were used to prepare technical descriptions of services. Data on needs and evidence of effective services were assembled into an interconnected matrix of information to advise the negotiations between the county authorities (the purchasers) and general practitioners, community services and hospitals (the providers). Results: Negotiations between purchasers and providers resulted in agreed specifications to commission services for people with ischaemic heart disease(IHD). Contracts for IHD services for 1996/7 will be based upon this method which applies to specific conditions instead of the previous historical cost and volume method. Use of the method has allowed target outcomes for services to be defined and agreed between the parties. Conclusion: Condition specific programmes of care appear to be feasible, relevant and potentially beneficial. It is possible to gain the co-operation of both managers and clinicians in defining service specifications, which are related to measured need and scientific evidence of effectiveness, for people with ischaemic heart disease. Initial failings of the market, in particular confrontation between purchasers and providers, can be reduced. J Epidemiol, 1996 ; 6 : S89-S92.
In Japan, epidemiological studies on intractable diseases have been undertaken and greatly promoted, in the recent two decades, by the Research Committee on Epidemiology of Intractable Diseases, with the financial supports from the Ministry of Health and Welfare of Japan. In this paper, chronological development of the Research Committee and some scientific accomplishments in the recent several years were summarized, mainly focusing on descriptive and analytical epidemiological studies. Highly hoped by the authors is that some foreign epidemiologists, who became acquainted with the recent research activities of the Research Committee on Epidemiology of Intractable Diseases, may seek for possible international collaborations in epidemiological studies on certain intractable diseases with Japanese epidemiologists. J Epidemiol, 1996 ; 6 : S99-S109.
Converging evidence indicates that diet contributes to the etiology of about 1/3 of fatal cases of human cancer in the developed countries. Although incomplete, the existing knowledge provides the foundation for an effective policy of primary cancer prevention through diet modification. A prudent diet that reduces cancer should be high in vegetables, fruits, legumes and cereals, and low in red meat, salt and saturated fat of animal origin. Added lipids should be of plant origin and, among them, olive oil has a safety record of several thousand years. Obesity should be avoided mainly by increasing physical activity. Regular physical activity during childhood and adolescence may also slow down excessive growth, as reflected in attained height, and have beneficial consequences on several cancer types. Concerning alcoholic beverages, a strategy that could preserve most of the health benefits of alcohol intake and could reduce the alcohol-related cancer mortality would include: for everyone, reduction of heavy alcohol consumption; for smokers limitation to alcoholic beverages that are taken with meals (mainly wine); for nonsmoking men encouragement of moderate drinking (up to 2 glasses per day); for nonsmoking women encouragement of light drinking (one glass per day), unless they are at high risk of developing breast cancer. J Epidemiol, 1996 ; 6 : S111-S115.
The Americas have accounted for the highest number of reported cases of AIDS of any region in the world since the beginning of the epidemic, primarly due to the high number of cases reported in the United States and Brazil. The characteristics of the epidemic vary by country, some countries having a pattern similar to the United States (HIV infection primarily among men who sex with men and intravenous drugs users) and others having patterns similar to Africa (HIV infection primarily through heterosexual transmission). The magnitude of the epidemic is difficult to determine in many of the countries of the region because of the low proportion of AIDS cases that are reported and because surveillance for HIV infected individuals among risk groups is conducted in very few of the countries. Although knowledge of HIV/AIDS is reasonably high in the region, knowledge alone has been demonstrated to be insufficient to alter behavior, especially among economically deprived groups. Nonetheless, in the absence of an effective vaccine and affordable treatment, health education and behavioral intervention remain the key weapons in the fight against the epidemic in the majority of the countries of the region. J Epidemiol, 1996 ; 6 : S117-S119.
Sub-saharan Africa is the region that has been hardest hit by the HIV epidemic; containing 63% of the estimated world total of HIV infections. In some east, central and southern African countries infection rates among adults in excess of 20% have been recorded. The demographic, social and developmental impact of the AIDS epidemic is likely to be huge in the next decade. Strategies that have potential for reducing the spread of the epidemic in this part of the world must be continuously explored and implemented. In this paper behavioural interventions that include condom use, and improved management of STDs are discussed. J Epidemiol, 1996 ; 6 : S121-S123.
It was estimated that 4.8 million people in Asia were already infected with HIV. Many countries including India, Myanmar, Thailand, Cambodia, some part of Vietnam and China is experienced a severe HIV epidemic. All categories of HIV risk behaviors and factors are known to exist in most countries of the region but with different degree. Experiences and lessons from some countries such as Thailand suggested that to effectively prevent HIV, it is necessary to have a national AIDS program, adequate budget from the country, and with partnerships from all government and non-government sectors. There are five important strategies which should be implemented with wide coverage: STDs service, condom promotion in all sex establishments, HIV screening for blood supply, HIV surveillance and information dissemination through mass media. With this prevention strategies, there is evidence of decrease of STDs and declining of HIV infection among young Thai male. Because HIV is the effect from poverty, inequality of socioeconomic development, National AIDS program should not neglect the opportunity to reform the unfavorable social or economic situation. Asian countries can and must strengthen their collaboration for joint HIV control program with full commitment and contribution. J Epidemiol, 1996 ; 6 : S125-S128.
The European region counts some 850 milions inhabitants living in 50 different countries, and the analysis of the epidemic situation reveals complex patterns of pictures and dynamics. Such analysis are facilitated by the fact that a common information system has been developped in the European region since 1984. 44 out of the 50 countries are participating in that system, by providing standardized AIDS/HIV surveillance data to the European Centre. J Epidemiol, 1996 ; 6 : S129-S131.
Though the number of HIV/AIDS cases is relatively small in Japan, it has been increasing steadily especially among Japanese male. Nearly half of all HIV infections was transmitted through the transfusion of HIV-infected blood products. However, new infections have been occurring mainly through heterosexual transmission. By the end of June 1996, cumulative total of 1, 312 AIDS cases and 3, 758 HIV infections are reported. Of 682 AIDS cases, excluding those infected through the transfusion of infected blood products, heterosexual transmission accounts for 39%, homosexual/bisexual transmission accounts for 30%, the sharing of HIV-infected injection equipment by drug users accounts for 0.9% and mother-to-child transmission accounts for 1%. Of 1, 890 HIV infections, excluding those infected through blood products, heterosexual transmission, homosexual/bisexual transmission, injecting drug use and mother-to-child transmission accounts for 50%, 21 %, 0.6%, 0.6% respectively. HIV infections have been reported from all prefectures and most infected individuals now mention Japan as the place where transmission took place. Japanese National AIDS Program consists of six areas ; health care, counseling system, HIV testing, research, education and international cooperation. In 1996, the Government puts particular emphasis on improvement of health care for those who are infected. J Epidemiol, 1996 ; 6 : S133-S137.
Human activities, such as combustion of fossil fuels, agricultural activities and changes in land- use, are responsible for global climate change. Because of the rapid increase of anthropogenic greenhouse gas emissions (carbon dioxide, methane and nitrous oxide), climate models predict an increase in global surface temperatures of 1.0°C to 3.5°C by the year 2100. Using general circulation models, it is estimated that surface temperatures in and around Japan will rise 1°C to 3°C during the next 100 years. Because global warming may increase the frequency and length of high temperatures during hot summer months in temperate regions, various health risks caused by heat stress have been studied. According to an epidemiological survey, the incidence of heat-related illness was significantly correlated to hot environments in Tokyo, Japan and in Nanjing and Wuhan, China. The epidemiological results showed that the incidence of heat related mortality and morbidity, such as heat stroke in the elderly, increased very rapidly when daily maximum temperatures in summer months rose above 31°C in Tokyo and 35°C in Nanjing and Wuhan, respectively. J Epidemiol, 1996 ; 6 : S141-S144.
The United Nation's Intergovernmental Panel on Climate Change estimates an unprecedented global rise of 2.0°C by the year 2100. Such change can affect serious infectious diseases, including dengue fever and malaria. Both large-scale iterative modeling and site-specific microclimatic analysis of disease ecology are needed in tandem to address health effects of climate change scenarios. In two separate studies of dengue and malaria transmission, both General Circulation Models (GCMs) of global climate change and site-specific climate analysis are used respectively to investigated climate change impacts on dengue fever and malaria transmission risk. For the first study, analysis was conducted using the integrated MIASMA model to link GCM projections of climate with a vectorial capacity model of transmission. Preliminary results indicate climate conditions being more suitable to dengue transmission, given viral introduction. An expansion of potential epidemic risk both geographically and temporally is inferred from this study. In the malaria study, preliminary results from regression analysis show mosquito biting rates to correlate to ambient temperature and rainfall. Parasite development was also shown to relate to temperature and humidity. Further interdisciplinary cooperation and multi-scaled analytical approaches will be required to better assess the potential effect of climate change on malaria and dengue. J Epidemiol, 1996 ; 6 : S145-S148.
A direct impact on human health as a result of increasing atmospheric concentrations of C02 could be more frequent exposure to increased daily average surface temperatures and increased daily average atmospheric concentrations of air pollutants. These exposures would occur most often in urban areas. To evaluate the impact of the combined exposures to increasing temperatures and air pollutant concentrations on the risk of heat and air pollution mortality, a second moment reliability method of analysis was used. The method required distribution functions for mortality, temperature and air pollutant concentrations. To demonstrate how this method can be used to predict changes in mortality risk, data were used on cardiovascular and respiratory mortality, daily average temperatures and daily average air pollutant concentrations for the city of Los Angeles from 1970 to 1979. Using time-series analysis of these data, regression formulas for mortality for different ages groups were quadratic functions of temperature and linear functions of air pollutant concentrations. At fixed temperatures, the second moment method was used to show that specific reductions in mortality for all age groups could be achieved by specific reductions in air pollutant concentrations. This provides a method to evaluate mortality risk reductions of technologies being developed to mitigate climate change because reductions in atmospheric concentrations of C02 would usually be accompanied by decreasing concentrations of air pollutants. J Epidemiol, 1996 ; 6 : S149-Sl51.
The study and comparison of warming, mosquitos of genus Anopheles and transmission of malaria in the North of Argentina allow to conclude that a possible change could happen. Warming may have three principal impacts in the epidemiology of this and other vector-borne diseases: a) to shorten vector life cycles; b) to increase the necesity of blood intake by haematophagous insects; c) to increase the risk of bites and transmission of pathogens. J Epid emiol, 1996 ; 6 : S153-S157.
Increased combustion of fossil fuels, along with many industrial and agricultural activities are resulting in greater emissions of greenhouse gases such as carbon dioxide, methane and nitrous oxide into the atmosphere. The continuing increased emissions of these greenhouse gases is contributing to global warming and climate change because of the greenhouse effect. Global warming may become a critical issue for increased frequency and severity of heat stress morbidity and mortality in summer, increased exposure to air pollution, and the spread of vector- borne and water-borne infectious diseases from tropical latitudes to more northern and southern latitudes and higher elevations. In this symposium, four presentations will discuss the possible impacts of global warming on a higher incidence of heat stress related mortality and morbidity, expansion of regions for vector- borne and water-borne diseases, contribution of higher temperatures and air pollution to mortality, and the possible relationship of El Nino-Southern Oscillation to the spread of malaria to more southern latitudes and higher elevations. J Epidemiol, 1996 ; 6 : S159-S160.
Although most are first-generation immigrants, the Korean population of Los Angeles, USA, showed a different pattern of cancer incidence to Korean residents of Seoul. Among Koreans in Los Angeles, the incidence of cancer, at all sites, was lower than in Seoul, both in males and females; among males aged 40-59 and females aged 30-49, the incidence was markedly lower. For several sites of cancer, for example the stomach, liver, and bladder in males and the cervix uteri and liver in females, the incidence for U.S. Koreans was significantly lower. Furthermore, for several sites, mean age at diagnosis was lower in Seoul than in Los Angeles. For Korean males in Seoul, the seven leading sites of cancer, namely the stomach(26.4 %), lung(16.2%), liver(14.4 %), colo-rectum(8.9%), bladder(3.9%), gallbladder(3.8%), and pancreas(2.7 %), accounted for three-quarter(76.3 %) of all cancers occurring. For Korean males in Los Angeles, the seven leading sites were the stomach(22.9%), lung(21.1 %), liver(11.1 %), colo-rectum(6.8%), prostate(4.9 %), non-Hodgkin's lymphoma(3.3%), and gallbladder(2.8%), and comprised 72.9 % of all cancers. In females in Seoul, the seven leading cancer sites, comprising 75.8% of all cancers, were the cervix uteri(20.5 %), stomach(16.9 %), breast(11.6%), colo-rectum(9.0%), liver(6.7%), lung(6.6 %), and thyroid(4.5%). Among females in Los Angeles, the sites were the stomach(18.0%), cervix uteri(13.6%), breast(13.3%), lung(9.7 %), colo-rectum(9.6%), thyroid(5.6%), and liver(3.1 %), and comprised 72.9 % of all cancers. J Epidemiol, 1996 ; 6 : S161-S164.
Singapore is a veritable human laboratory for the study of cancer patterns, with a compact population (3m) on a small island (640 km2). The ethnic distribution indicates that 78% are Chinese, 14% Malays, 7% Indians and 1 % Others. The validity of ethnic distribution remains, with less than 5% of marriages being inter-ethnic even today. Recently, a full analysis of incidence trends over 25 years (1968-1992) was completed. The age-adjusted relative risks confirmed high risk in Chinese for nasopharynx, oesophagus, stomach, colon, rectum, liver and lung. In Indians, high risk sites were mouth and cervix, and in Malays, ovary and non-Hodgkin's lymphoma. Of special interest are the following: (a) sharp increse in female breast cancer, attributed to a strong cohort effect, thus suggesting the role of lifestyle changes and the finding of a likely protective effect of soya bean products; (b) marked increase in colorectal cancer, partially explained by the high meat: vagetable intake ratio and reduced cruciferous vegetable intake in the high risk group; (c) unchanging incidence of nasopharyngeal carcinoma, and the finding of salted and picked vegetables as a risk factor; (d) increasing proportion of adenocarcinomas (50%) of the lung in female Chinese, which cannot be explained by cigarette smoking and remains a research topic. J Epidemiol, 1996 ; 6 : S165-S168.
Brazil's total Japanese population was estimated at 1.2 million in 1988, 290 thousand of whom lived in the city of Sao Paulo. The authors investigated their cancer patterns and their lifestyle. When the age-adjusted rates of cancer incidence among Japan-born immigrants were compared with those among Japanese in Japan, the rate of cancer of the stomach in both sexes, pancreas and lung in men and rectum in women were significantly lower, while non-melanoma skin cancer, prostate and breast cancer were higher. No significant increase of colon cancer was recognized. The mortality data showed a similar trend, although no significant decrease of stomach cancer was detected in either sex. A cross-sectional study of randomly selected Japanese residents in the city of Sao Paulo showed some lifestyle modifications when the results were compared with data from a cross-sectional study conducted in five Japanese populations in Japan using similar protcol. Japanese Brazilians smoked less and drank less. Their dietary habits were more like the pattern seen in Western countries with higher intake of beef and dairy products, although they consumed vegetables more frequently. Serum level of total cholesterol, uric acid and total carotene revealed significantly higher values, while serum selenium was much lower than Japanese in Japan. The differences in lifestyle shown between Japanese residents in Sao Paulo and in Japan were discussed in relation to the cancer pattern between them. J Epidemiol, 1996 ; 6 : S169-S173.n-abstract=
Three folds Japan-Indonesia joint study on breast cancer has been conducted, i, e, epidemiological, clinical and histopathological aspects. Case-control study was used throughout as standard method. Hisopathologically confirmed breast cancer cases were women aged 25-69 years with primary tumor. The study was performed in two batches, i.e. during the first batch 300 cases and 600 controls, and during the second batch 226 cases and 552 controls were collected. The epidemiological study revealed that in premenopausal breast cancer increased risk was related to breast trauma, contraceptive use, milk and fresh fruits intakes ; while decreased risk was related to cooked vegetable intake. In postmenopausal breast cancer increased risk was found in age at menarche of 15 years or over, regular menstruation after 30 years, and milk consumption ; while decreased risk was related to divorced or widowed status, and number of live births or children breast-fed. The clinicopathological findings showed that the Indonesian breast cancer had already occured more frequently at younger age group (10-29 years) and peaked at 40-49 years group. The majority was at advanced stage, the stage I and II was 2% and 15.3% respectively. In contrast, the majority of Japanese cases were at early stage. The majority (88.33%) of Indonesian breast cancers was the invasive carcinoma, while 1.33% was the noninvasive carcinoma and 9.67% was the special type. Medullary carcinoma was found more frequently among the Indonesian females as compared to the Japanese females. Further nutritional analysis showed that certain micronutrients increased the risk such as fat, animal protein, mineral, calcium, phosphate, ferrum. Retinol, thiamin and ascorbic acid of the postmarriage intakes might contribute to the risk, while such indication was not shown by the premarriage intakes. The importance of the interaction of certain micronutrients instead of interpreting the effect of individual nutrient separately has to be considered. J Epidemiol, 1996 ; 6 : S175-S180.
Cancer patterns in different racial/ethnic groups in different areas were presented at a symposium in the 14th International Scientific Meeting of the International Epidemiological Association; Koreans in Korea and Los Angeles, Japanese in Japan and Sao Paulo, and Chinese, Indians and Malays in Singapore. The findings from these descriptive epidemiology suggested the effects of environmental factors in the etiology of various cancers appear during relatively short period at least in a generation. Comparison of hormonal profiles in populations at the extremes of incidence of prostate cancer, which shows one of the remarkable racial-thnic variation, indicated that the difference may be due to variation in testosterone secretion and testosterone metabolism. It was also suggested that these hormonal differences might be genetically regulated. Two case-control studies of breast cancer in Indonesia and Japan suggested that the risk factors for the disease are almost the same in the two countries but the investigators found large differences in the stage and age at diagnosis of the cancer. J Epidemiol, 1996 ; 6 : S181-S182.
We presented trends of cardiovascular risk factors and diseases in a rural population, northeastern Japan between the 1960s and the 1990s. Population blood pressure levels declined substantially with improved medical treatment for hypertension and reduction of mean dietary sodium intake from 20g/day to 14g/day. Serum total cholesterol increased from 152mg/dl to 185mg/dI for men, and 163mg/dI to 195mg/dI for women with an increased intake of meat, egg, milk and dairy products. Age-adjusted incidence rate of stroke declined 75% while that of coronary heart disease was low and stable. The prevalence of stroke and the number of stroke patients also declined in spite of an increase of the elderly. Furthermore, the number of severely- disabled stroke patients, so called bed-ridden patients decreased a half. The substantial decline in stroke incidence, prevalence along with the decline of blood pressure levels suggest an effect of population hypertension control program conducted since 1963. In nationwide, however, an increase in the prevalence of stroke patients and the number of severely disabled patients among the elderly were reported. Primary prevention of stroke through control and prevention of hypertension should be further augmented nationwide to reduce a public health burden from the disabled stroke patients in the elderly. J Epidemiol, 1996 ; 6 : S183-S188.
The aim of this report is to describe age-adjusted death rates from ischemic heart diseases (IHD) and cerebrovascular diseases (CVD) in recent years and secular trends in the selected countries. World Health Statistics Annuals by the World Health Organization were used for data sources. From 1994 annual statistics, among males, the countries with the highest age-adjusted death rates were as follows in decreasing order: Hungary, former Czechoslovakia, the United Kingdom, Ireland and Finland for IHD; Bulgaria, Hungary, Portugal, former Czechoslovakia and Poland for CVD. On the other hand, the countries with the lowest rates were as follows in increasing order: Japan, France, Spain, Portugal and Italy for IHD; Switzerland, Canada, the United States, France and Australia for CVD. The trends of age-adjusted death rates both in IHD and CVD for 1970-1994 decreased in the United States, Australia, Western and Southern Europe and Japan, while both IHD and CVD rates tended to increase in Eastern Europe. Decreasing trends seen in the countries that already showed marked decrease in 1970s through the mid 1980s, seemed to be blunted in recent years. Some countries whose death rates were relatively high showed decreasing trends that lagged behind the other countries: Spain, Poland and Greece for IHD; and Hungary for CVD. J Epidemiol, 1996 ; 6 : S189-S196.
The NI-HON-SAN Study begun in 1965, and is a comparative study of cardiovascular disease and associated risk factors in Japanese living in Japan, Hawaii, and San Francisco. Early comparisons showed the prevalence of stroke to be the highest in Japan, intermediate in Hawaii, and the lowest in California. The trends for the prevalance of coronary heart disease in these three areas on the other hand were found to be completely opposite to those of stroke. Comparisons of risk factors demonstrated no difference in blood pressure levels, whereas the mean serum cholesterol level and body mass index were the lowest in Japan. A major difference in intake of total and saturated fats was noted between these three areas with the lowest values noted in Japan. The NI-HON-SAN Study demonstrated that a change to a Western life-style had a favorable effect in reducing stroke but conversely resulted in increase of coronary heart disease. The message to be noted is that an excessive change to a Western life-style should be avoided in developing countries, where rapid economic growth is taking place. J Epidemiol, 1996 ; 6 : S197-S201.
Concern about rising coronary heart disease (CHD) death rates and awareness of international differences in CHD and stroke mortality led to early epidemiological studies including Framingham Heart, Seven Countries and NI-HON-SAN studies. Elevated blood cholesterol and blood pressure, cigarette smoking and diet were identified as risk factors, predominantly in men. Clinical trials demonstrated the feasibility and efficacy of lowering risk factors through pharmacologic and behavioral interventions. The continuing decline in CHD mortality began in the late 1960's and is attributable to healthier lifestyles and improved medical management. Current epidemiological studies include more women and diverse populations and expand potential risk factors and outcomes to include obesity, diabetes, hemostatic and psychosocial factors, physical inactivity and genes, as well as markers of pre-clinical atherosclerosis, ischemia, and cardiac dysfunction. CVD prevention encompasses national education programs, community interventions and high risk approaches. In the future new insights are expected on the interplay of genetic susceptibility and non-genetic risk and protective factors and on precipitants of clinical events. Advances in treatment and wider use of preventive measures should reduce or delay CVD especially among low socio-economic groups, the elderly and survivors of an event. National goals for lower rates of CHD, stroke and risk factors have been set for the year 2000. J Epidemiol, 1996 ; 6 : S203-S207.
This paper used official mortality data for Australia; data on incidence of coronary events and levels of risk factors from the World Health Organization's MONICA Project (to MONItor trends and determinants of CArdiovascular disease) in Newcastle, New South Wales, Australia; and national data on coronary procedures and medications to show the past trends and present situation of cardiovascular disease (CVD) in Australia. There are well-established trends of declining rates of deaths from all causes, CVD, coronary heart disease and stroke and of non- fatal coronary events (which are also becoming less severe). The three major risk factors of cigarette smoking, high blood pressure and high blood cholesterol have also been declining for some time. Despite this picture, which is encouraging from a population perspective, the medical costs of CVD are rising. This is due to increases in medical and surgical procedures and the use of increasingly expensive drugs. The challenge for public health is to keep the focus on prevention, including attention to the increasing prevalence of overweight and obesity. J Epidemiol, 1996 ; 6 : S209-S213.
The history of epidemiology and progress in the prevention of cardiovascular diseases (CVD) in various parts of the world were described in presentations by six speakers. In the area of research, emphasis was placed upon the need for more extensive studies including the study of CVD in women as well as examination of not only the three major risk factors of elevated cholesterol, elevated blood pressure and cigarette smoking but also of obesity, diabetes, hematostatic factors, psychosocial factors, physical inactivity, genetic factors, gene-environment interactions, etc. The population strategy and high-risk strategy were described for CVD prevention, but the cost of the high-risk strategy is relatively high, and the efficacy and usefulness of the more economical population strategy were stressed. J Epidemiol, 1996 ; 6 : S215-S218.
Never before have so many people lived so long. Ageing has not yet been defined as an issue in many developing countries, but already two thirds of the net annual increase in the number of older women in the world is occurring in less developed countries. The key features are an increasing life expectancy and increasing proportion of the population who are elderly, the ageing of the older population itself, and the great diversity in ageing between countries, in particular, the rapidity of ageing in developing countries and newly industrialised countries. The implications for women are considerable since women are more likely to survive to older ages, are more likely to be economically disadvantaged, and because they assume most of the burden of care of infirm elderly people. Changes in the life course of ageing women have significant implications and their health status reflects the compounding effects of age and gender differences as well as the cultural context in which ageing occurs. As yet, there is no clear evidence that women's greater life expectancy has any significant advantage in the proportion of remaining years lived free of disability. The multidimensional determinants of health of older women mean that strategies to improve and maintain health must also address their disadvantaged status. J Epidemiol, 1996 ; 6 : S219-S223.
Along with the lengthening life span, maintaining good quality of life in the elderly is an important goal. We determined frequency and risk factors for osteoporosis and associated fractures among a Japanese cohort in Hiroshima and Nagasaki, known as the Adult Health Study (AHS). We found lower bone mass and a higher vertebral fracture prevalence among Japanese women, compared to women of Japanese descent living in Hawaii and American Caucasians. However, the incidence of vertebral fracture has decreased progressively among successive younger Japanese birth cohorts. These findings suggested that environmental factors probably play an important role on occurrence of osteoporosis and vertebral fracture. Age, sex, weight, menstrual history, and calcium intake were associated with bone mass and vertebral fracture prevalence. From the AHS cohort study, age, body mass index, age at menarche, and number of children, milk intake, alcohol intake, and prevalent vertebral fracture were related to the risk of hip fracture. Risk factors for falls, such as alcohol consumption, may be responsible for occurrence of hip fracture in addition to the risk factors related to bone mass. Elucidating risk factors related to bone mass, bone quality, and falls may lead to new strategies for preventing osteoporosis and associated fractures. J Epidemiol, 1996 ; 6 : S225-S229.
A review of published epidemiological studies on lung cancer consistently shows Chinese females in China, Hawaii, Hong Kong, Singapore, and Taiwan having low relative (2-4) and attributable risks (-1/3) from smoking. However, female lung cancer incidence/mortality rates within China are variable, with some comparable to the lowest rates in other parts of the world. This variablity suggests the role of environmental etiological factors. Research on risks from inhaled air pollutants indicate that smoky coal used for cooking and heating in the colder parts of NE and SW China increased risk for lung cancer. However, risks from other air pollutants like environmental tobacco smoke, cooking fumes, and cooking oils were equivocal, and that for mosquito coil, incense, and other cooking fuels showed no risk. Risk from the effects of diet are inconsistent, with some studies from China showing increased fruit and vegetable intakes associated with increased risk. However, dietary results from Chinese communities outside China (Hong Kong, Singapore, Taiwan) are more similar to risks found among Western societies. There was some indication that previous respiratory diseases like chronic bronchitis and tuberculosis may be associated with lung cancer risk, but these results may be due to prodromal symptoms and recall bias, respectively. The role of reproductive health factors like parity, age at menopause, menstrual cycle length, etc. is unclear. Hence, aside from smoky coal exposure in cold and less developed parts of China, the etiological factors causing high lung cancer rates among Chinese women living in affluent urban warm climates like Shanghai, Hong Kong, Singapore, and USA remain unclear. J Epidemiol, 1996 ; 6 : S231 -S236.