World health situation and trend assessment from 1948 to 1988.

d ate / ~~~~~~thepresent position in the tion actuelle dans les do-/ofpt selectedfields,coveringmany maines consideres, couvrant / / / ~~~~~~~different aspects of the de nombreux aspects des / biomedical sciences and sciences biomedicales et de la Lepo n t public health. Most of santepublique. Laplupart de the articles are written by ces articles auront donc ete acknowledged experts on the rediges par les specialistes subject. les plus autorises. Bulletin of the World Health Organization, 66 (6): 679-687 (1988) © World Health Organization 1988 World health situation and trend assessment from 1948 to 1988* K. UEMURA1 Although the Health Situation and Trend Assessment Programme ofWHO was estab- lished only in 1982, its two main components (epidemiological surveillance and health statistics) were infact carried out as a constitutional mandate ofthe Organization since its creation 40 years ago. The evolving world health situation and the changing requirements ofMember States have always been taken into account in carrying out these functions. In the early days of WHO, standardization ofstatistical definitions, methods and procedures was given top priority, while during the second and third decades active participation in epidemiological and statistical research was also emphasized. In the meantime, technical cooperation with Member States gained in importance. During the most recent decade, the programme was reformulated with a new orientation, stressing the importance of generating and using the most essential information to support health system management towards the goal of health for all. A number of issues still remain as challenges to the programme for the coming decade and beyond. These developments over the 40 years are reviewed in the present article, with a certain amount of focus on the research and development aspect. INTRODUCTION WHO's Health Situation and Trend Assessment Programme was started in 1982 by merging two programmes-on health statistics and on epidemio- logical surveillance of communicable diseases- which had been functioning as an essential part of the mandate of WHO since its creation in 1948. Indeed, the activities in health statistics and epi- demiological surveillance, which were inherited * A French translation of this article will appear in a later issue of the Bulletin. ' Director, Division of Epidemiological Surveillance and Health Situation and Trend Assessment, World Health Organization, 1211 Geneva 27, Switzerland. Requests for reprints should be sent to this address. from WHO's precursors (the Office International d'Hygiene Publique, the Health Organisation of the League of Nations, and the Health Division of the United Nations Relief and Rehabilitation Adminis- tration), are mentioned in Article 2 of the Consti- tution of WHO, as follows: "(f) to establish and maintain such administrative and technical services as may be required, including epidemiological and statistical services;" "(q) to provide information, counsel and assist- ance in the field of health;" and "(s) to establish and revise as necessary inter- national nomenclatures of diseases, of causes of death and of public health practices." Related obligations of the Member States are de- 4928 -679- 680 K. UEMURA scribed in Articles 63 and 64 of the Constitution which state, respectively, that "each Member shall communicate promptly to the Organization important laws, regulations, official reports and statistics pertaining to health which have been published in the State concerned", and that "each Member shall provide statistical and epidemiological reports in a manner to be determined by the Health Assembly". These statutory functions have continued to be the basis of programme activities in the area of epi- demiological surveillance and health statistics. The evolving world health situation and the changing requirements of Member States have always been taken into account when carrying out these functions. This review of the developments in this area, over the 40 years of WHO's existence, focuses on the scientific aspects but does not cover many of the epidemiological studies undertaken by the various programmes responsible for disease prevention and control, such as morbidity surveys, field trials of vaccines, etc. THE FIRST DECADE: 1948-58 During this period, priority was given to the man- dates inherited from WHO's precursors mentioned above. In particular, the first World Health Assembly in 1948: (1) adopted WHO Regulations No. 1 regarding nomenclature (including the compilation and publi- cation of statistics) with respect to diseases and causes of death; and (2) decided to synthesize the then existing inter- national sanitary conventions, dealing, on the one hand, with maritime and land traffic and, on the other, with air traffic. The latter resulted in 1951 in the adoption, by the Health Assembly, of the International Sanitary Regulations as WHO Regulations No. 2, covering six quarantinable diseases -cholera, plague, epidemic (louse-borne) typhus, relapsing fever, smallpox and yellow fever.a Thus the activities to develop and administer the International Sanitary Regulations, to collect and dis- seminate epidemiological and health statistical infor- mation, and to revise the International Nomenclature Regulations and the International Classification of Diseases and Causes of Death were given high pri- ority. To promote international comparability of epidemiological and statistical data collected by countries and reported to WHO was the main concern a The Regulations were revised and consolidated as the Inter- national Health Regulations in 1969. They were further revised in 1973 with regard to the provisions for cholera and again in 1981 to exclude smallpox which had been eradicated from the world. expressed by the Member States. Standardization of the concepts, definitions, procedures and tools such as the classification of diseases and causes of death was considered as the most important task which WHO should undertake to achieve that purpose. To facilitate this task the Health Assembly requested the WHO Expert Committee on Health Statistics to formulate recommendations on these issues. At this time many of the now independent countries in the African continent were still under colonial rule; for example, there were only 3 Member States in WHO's African Region in 1958, compared with 44 Member States and 1 Associate Member in 1988. As a consequence, the concerns of the more advanced countries were much more strongly reflected in the Organization's policy than in the later decades. The great (perhaps slightly excessive) emphasis made by Member States on the need for developing and applying standard terminology, definitions, methods and procedures so as to make the information pro- duced by countries internationally comparable can be understood in the light of the political environment prevalent at that time. The WHO Expert Committee on Health Statistics devoted itself to the standard- ization of such topics as the death certificate, the underlying cause of death, perinatal statistics and definitions, cancer registration, and hospital statistics. It is interesting to note that during the first decade of WHO's existence a number of articles analysing and interpreting the morbidity and mortality data officially reported by countries, including their trends, were published in the monthly Epidemiologi- cal and vital statistics report. Almost forgotten today, some of these studies still provide potentially useful references in health trend analyses, especially when the coverage of the last several decades is needed. The topics frequently chosen in these reports were the incidence ofvarious communicable diseases, mor- tality from selected communicable diseases, infant mortality, etc. As mortality statistics were not yet reported by many countries to WHO, detailed mor- tality analysis was often confined to data from Euro- pean countries. Timely dissemination of epidemiological infor- mation, e.g., on the occurrence of certain communi- cable diseases which are of international interest, has been given high priority throughout the 40 years of WHO's work. Information received from countries has been processed and feedback provided to all countries without delay through the Weekly epidemio- logical record, and more recently through an auto- matic telex reply service as well. Developments also took place, however, to advise and assist Member States in improving their epi- demiological and statistical data collection and reporting to WHO. In emphasizing the need for HEALTH SITUATIONS AND TREND ASSESSMENT, 1948-88 681 technical assistance to strengthen national capacity in health statistics, a review of the first 10 years of WHO's work went so far as to state that "the countries giving satisfactory information, both on the actual occurrence of death and on its causes, could be numbered on the fingers of one hand" (1). The WHO Regional Offices have been in the fore- front to support Member States in strengthening the national epidemiological and statistical services. By the early 1950s the World Health Assembly approved annual budgets providing for the posts of regional advisers in health statistics, whose main duties were to give advice and assistance to countries in the organ- ization of health statistical services. Development of vital statistics and civil registration was given priority. Similar duties regarding epidemiological surveillance were assumed by regional advisers in communicable diseases, which were also provided for in the annual budgets. A series of seminars and training courses were held to improve national vital and health statistics and surveillance of communi- cable diseases. A number of projects were started during this decade to determine the prevalence and incidence of specific diseases in countries, such as tuberculosis, diarrhoeal diseases, trachoma, yaws and malaria. These were based on household surveys using prob- ability sampling methods, and produced scientifically valid estimates on these diseases for the first time. Unfortunately, it was not always possible to make the best use of these results for the development and improvement of disease control measures, owing to lack of national resources to undertake appropriate action. An interesting attempt was made to devise a method for making use of data collected by non-medical per- sonnel for studying crude cause of death, e.g., in countries in the African continent." The issue was, however, not pursued beyond a few years and forgotten until 20 years later when the idea of "lay reporting" aroused again the interest of health workers in the developing countries (see below). The first decade was the period when there were great hopes for constructing a peaceful world and enhancing the level of living through the United Nations system. One of the topics which was en- trusted to the statistical services of the international organizations was the development of methods to measure the level of living. The Economic and Social Council (ECOSOC) of the United Nations recom- mended that, even if it would be impossible to develop a single index to measure the level of living and its changes, efforts should be made to find an b BIRAUD, Y. Methode pour 1'enregistrement par des non- medecins des causes e'lmentaires de decs dans les zones sous- developpees. Unpublished document WHO/HS/60, 1956. indicator of each of its components. The ECOSOC produced a list of 12 components for this purpose, the first of which was "health, including demographic conditions". WHO's response to this recommen- dation was the proposal of a promising indicator called the proportional mortality ratio, i.e., the number of deaths ofpersons aged 50 years and over as the percentage of total deaths, which could be calcu- lated with reasonable precision using routinely col- lected vital statistics in many countries (2). THE SECOND DECADE: 1958-68 The second decade saw a continuation and further development of the priority activities of the first decade. Two noteworthy areas were the expansion of "technical assistance" to Member States and the emphasis given to international collaborative studies, including statistical support to epidemiologi- cal research on diseases of public health importance. Collaborative studies of these diseases, undertaken during this and the subsequent decades, were con- sidered important in order to obtain clues on their complex etiology. A project of major statistical importance was car- ried out in the American Region on the patterns of urban mortality. This coordinated international research, funded by the U.S. National Institutes of Health, was prompted by the fact that official statistics had shown striking variations among countries in the death rates from arteriosclerotic and degenerative heart disease. Twelve cities in eleven countries (including one in England and eleven in the American Region) were included in this study with the primary objective of providing a comprehensive account of the causes of mortality of adults in highly diverse and widely separated populations. Standard procedures established by the investigators were followed in collecting field data and in reviewing, coding and analysing the data collected. The study led to a series of recommendations relevant to preventive actions, epidemiological research, and standard- ization of statistical procedures (3). The WHO Regional Office for Europe sponsored a series of studies in 1962-65 in six countries on the accuracy and comparability of death statistics. These studies found that many discrepancies occurred both in the certification of death by the attending physician and in the interpretation of death certificates by coders. The need for greater uniformity between countries was thus highlighted so as to make death statistics truly comparable (4). These two projects provided useful contributions to the development of later revisions of the International Classification of Diseases. 682 K. UEMURA The epidemiological and pathological study on atherosclerosis which was coordinated by the Car- diovascular Diseases Unit of WHO was among the first population-based, collaborative epidemiological studies. Five towns or cities (Prague, Malmo, Mos- cow, Kishinev and Yalta), in which most deaths were brought to autopsy, participated in the study. Speci- mens of the aorta and coronary arteries were collected from about 17 500 subjects during the period 1963- 65, treated by a uniform procedure, and examined by a group of pathologists for grading the extent of the atherosclerotic lesion in a standard manner. Both intra- and inter-observer errors were studied and con- trolled. The development of lesions with age, and their variation between the sexes, among different causes of death, and in relation to associated diseases such as hypertension and diabetes, were analysed. Among the many interesting findings obtained, the study revealed clearly the progression of athero- sclerotic lesions from childhood onwards, even among those who died in accidents and had no serious disease (5). Another collaborative study to which a consider- able amount of statistical support was provided was the international pilot study on schizophrenia which was organized by the Division of Mental Health and was started in 1965. Some 2200 patients from the participating centres in nine countries were included in the study using a detailed protocol. In view of the complex nature of psychiatric examination, special efforts were made to assess the reliability of the method$ used and to control observer variations. The large amount of data collected on each patient required elaborate statistical analysis (6). The emphasis given to these epidemiological studies was to support communicable and non- communicable diseases control on which numerous resolutions had been adopted by the governing bodies containing, inter alia, recommendations for ob- taining relevant epidemiological and statistical infor- mation. The priority given by the World Health Assembly to the active engagement of WHO in the conduct of epidemiological research led to the estab- lishment, in 1967, of the short-lived Division of Re- search in Epidemiology and Communications Science (RECS) which ceased in 1972. In response to the growing interest in sample sur- veys for collecting data which were not available through routine administrative channels, a series of papers were published on morbidity and mortality data obtained from surveys and other sources (7). THE THIRD DECADE: 1968-78 The 1960s saw the advent of computer technology in the health field. A computer was installed at WHO headquarters in 1966 and a considerable part of the statistical work was computerized during the third decade.' Statistical data processing was expedited and the computer made it practicable to store time series in an easily retrievable form, including the data received by WHO from Member States since 1950. Statistical analysis of the dose-response relationship required in the work on biological standardization and in the study of susceptibility of insect vectors to insecticide was also computerized. Much interest arose during this decade among epidemiologists and disease control managers in dynamic models of diseases. Typhoid fever, cholera, tetanus, diphtheria and whooping cough were among the diseases taken up for the development of epi- demiological models (8). A malaria model was also constructed by the RECS Division on the basis of a considerable amount of field investigations under- taken in Africa; this was perhaps the most significant scientific achievement made by that Division (9). The Tuberculosis Unit developed a model for tuberculosis and used it to estimate the effectiveness of tubercu- losis control measures (10). The heavy load of mathe- matical computation required in such modelling was made possible by the computer. The work of the RECS Division merits more de- tailed review than the sketchy description attempted in this article. However, broadly speaking, the Div- ision's overall failure to produce the coherent and integrated research programme foreseen at its estab- lishment, in spite of staff with high technical com- petence, should be ascribed primarily to its isolation from the other programmes of WHO. This clearly showed that epidemiology should be part and parcel of health research and would not be viable as a separ- ate and independent entity. In any case, the RECS Division was abolished in 1972 and towards the end of the decade the priority in research shifted from direct engagement of staff to a coordinating role of WHO. At the same time, certain statistical capability was gradually developed by several programmes of WHO, and the central support service to those pro- grammes was reduced. In the American Region an investigation was car- ried out on childhood mortality in 15 project areas in eight countries. This study, developed on the basis of the experience gained in the study of the patterns of urban mortality referred to earlier, aimed at estab- lishing death rates for infancy and childhood, taking into account biological as well as nutritional, socio- logical, and environmental factors. The results of the study have been quoted on numerous occasions in later work on infant and childhood mortality. The study revealed, inter alia, for the first time, three important determinants of infant mortality -birth ' The computer installation was transferred to the newly created International Computing Centre in 1971. HEALTH SITUATIONS AND TREND ASSESSMENT, 1948-88 weight, maternal age, and birth order (11, 12). A health demographic study was undertaken, with financial support fromUNFPA (United Nations Popu- lation Fund, previously called the United Nations Fund for Population Activities). Reliable data were lacking in many of the developing countries on fetal, infant and early childhood mortality and fertility. As the development of a complete registration scheme was a difficult and extremely slow process, a study was launched during this decade to substitute ad hoc sample surveys in order to obtain the information needed by health decision-makers (13). The project was carried out in five developing countries, with assistance from competent statisticians and demo- graphers provided by WHO. Useful and scientifically valid information was obtained for the first time in many of these countries. It is difficult, however, to judge whether the countries retained much technical expertise after the outside consultants had left. Another collaborative epidemiological study, of the kind referred to above in the section on the second decade, was carried out on acute myocardial in- farction by the WHO Regional Office for Europe with support from headquarters. Myocardial infarction had already been the cause of death in many of the industrialized countries, but there was little infor- mation on its incidence. This study, in which 19 centres in 16 countries participated, was the first attempt to register all cases of acute myocardial infarction occurring in communities. A standard protocol was developed, and the record forms filled in by the investigators during the period 1971-72 were analysed centrally at WHO headquarters. Besides geographical variations in the incidence rate and case fatality, the study showed a rapid evolution of the disease in most of the fatal cases that defied attempts to get medical help in time (14). A similar study was initiated, also in 1971, on the registration of cerebrovascular disease (15), from which the data collected were centrally handled and analysed at WHO headquarters. Later, these studies led to the more comprehensive MONICA project (monitoring trends and determinants in cardiovascular disease) which is currently under way in 41 collaborating centres (16). Along with the rapid development of automation in the industrialized countries, a new approach to health information was also advocated, so as to develop comprehensive computer-based management infor- mation systems. Based on this concept, efforts were made to develop national health information systems. Unfortunately, the attempts over the decade did not turn out to be successful. The main reasons for the failure were the overemphasis on computerization and a lack of clear recognition of the importance of the prerequisites to such computerization, e.g., the securing of adequate quality in source data, the ability to collect and prepare input to an automated system, and the capacity of health managers and decision- makers to utilize the output information to improve health care. The movement towards national health information systems, however, was not entirely in vain. By the end of the decade health planners and managers had begun to realize that the usual epidemiological and statistical reports they received did not suffice; infor- mation on budget and finance, availability and distri- bution of personnel, stocks of supplies, transport facilities, etc. had also to be taken into account to- gether with the data on disease occurrence and utili- zation of services given in the routine reports. Some information has to be obtained from other sectors concerning matters closely related to health, e.g., economic development, unemployment, educational status and literacy, food supply, etc. All the relevant data must be assembled from these various sources and then analysed and digested by the health decision- maker. This kind of information support to manage- ment has to be organized using computer facilities if available, and realistic health plans must be made within the resource constraints. Thus the managerial purpose of the generation of information was recog- nized more clearly, and this was reflected in the reorientation of the programme during the fourth decade. THE FOURTH DECADE: 1978-88 By far the most significant events occurring during the new decade were the adoption of the Alma-Ata Declaration on primary health care and the launching of the Global Strategy for Health for All, as well as the accelerated decentralization of WHO's activities. At the same time, the planning of the WHO Sec- retariat's work was systematized through the intro- duction of medium-term programmes corresponding to each General Programme of Work of WHO, covering a six-year period. The programme-budget- ing and the monitoring and evaluation of the pro- gramme implementation were facilitated and more sharply focused by this process, especially since the introduction of the Seventh General Programme of Work for the period 1984-1989 which provided, for the first time, objectives and targets for the Health Situation and Trend Assessment Programme. This new programme was started in 1982, with particular emphasis on the target-oriented approach to infor- mation, and identified the following five target areas: - strengthening of countries' capacities for infor- mation support to health system management; -training in epidemiology and health statistics; -development of methodologies and standard tools; - global and regional monitoring of the health 683 684 K. UEMURA situation; and -epidemiological and statistical support to other WHO programmes. The basic aim of the programme is that top priority should be given to the use of relevant information, and only the most essential information, for the im- provement of the health system. Broad guiding prin- ciples for information support to health system management were elaborated and made available for testing in several countries. Development and use of a limited number of indicators on the socioeconomic situation, on health policy development, on health service delivery and on health status, for monitoring and evaluating health-for-all strategies at national, regional and global levels, were considered the key elements in the implementation of the new pro- gramme. The development and use of the regional targets and indicators in the European Region was the most conspicuous example of the new approach. The need for generating and using relevant information at subnational level as a means of assessing the degree of equity in health has been stressed since the outset of the formulation of the health-for-all strategy, and further highlighted in response to the priority accorded by the World Health Assembly to the strengthening of the district health system in 1987. The series of resolutions adopted by WHO's gov- erning bodies on these subjects have been the basis of the Seventh General Programme of Work and the corresponding medium-term programme for health situation and trend assessment, as mentioned before. The Eighth General Programme of Work for the period 1990-1995, which was approved by the Fortieth World Health Assembly in 1987, and the corresponding new medium-term programme repre- sent further development and refinement of the policy direction established in the Seventh Programme. The problems and deficiencies identified in the national reports on the periodic monitoring and evaluation of the health-for-all strategy have provided a basis for these adjustments (17). The ninth revision of the International Classifi- cation of Diseases (ICD-9), which was approved by the World Health Assembly in 1976, was introduced by Member States as from 1979 (18). By that time there was also strong demand for a statistical tool which could cope with the constraints existing in many of the developing countries, especially for recording and analysing health information by non- medical personnel. The ideas developed by Biraudd for use in the African continent during the first decade of WHO were thus revived and adjusted to the prob- lems encountered in other developing countries as well. A booklet on lay reporting (19) was published d See footnote b, p. 681. as the outcome of this new attempt, and the method has since been tested in several countries. As lay reporting must use locally prevalent terminology, it is impossible to establish a method or a procedure that is universally applicable. None the less, this publi- cation has stimulated the attention of public health personnel to the need for devising ways of recording and using health information best suited to the local conditions. As exemplified in lay reporting, much of the developmental work undertaken during this decade related to practical adaptation and application of the existing methodology in specific national and local conditions. Nevertheless, the programme, acting as a clearing house on statistical and epidemiological methodology, also initiated activities. The World Health Statistics Quarterly, which in the preceding decade used to disseminate statistical data in the raw form on morbidity and mortality, developed into a periodical carrying articles reporting on the results of statistical analysis, as well as on epidemiological and statistical methodology, related to a theme selected for each issue. The themes already covered are family health, health and women, mental health, accidents, environmental health, health economics, health infor- mation systems, health surveys and projections, health indicators, etc. One issue every year is devoted to disease prevention and control. With financial sup- port from UNFPA, several publications on mortality analysis have ben issued; topics dealt with were socio- economic determinants and consequences of mor- tality (20), sex differentials in mortality (21), inter- action between mortality and the family life-cycle (22), perinatal mortality (23), and new develop- ments in mortality analysis (24). Problems faced by countries in the generation and use of health care information were recently the subject of a round table (25). The European Regional Office was particularly active in assembling and disseminating methods for dealing with current public health problems. Publi- cations on measurements in health (26, 27) and health projections (28) are examples of this effort. Greater emphasis was given to health promotion and protec- tion than disease control, in line with the health-for- all strategy, and particularly the regional targets and indicators adopted by the WHO Regional Committee for Europe. Work on the tenth revision of the ICD, which was to be adopted by the Health Assembly around 1985, had to be postponed. This was partly due to the con- straints imposed by the decentralization of WHO's resources and partly due to the considerable costs Member States would incur in changing the classifi- cation, which is a statistical tool now widely used in hospitals, in social security and epidemiological HEALTH SITUATIONS AND TREND ASSESSMENT, 1948-88 studies, as well as in coding medical certificates of death. The postponement by about 5 years was there- fore proposed by the Director-General of WHO and agreed upon by a majority ofMember States. This has allowed time to test proposals for the revision of the ICD and for new definitions and coding rules. A net- work of collaborating centres for the classification of diseases has been assisting this developmental task. The International Classification of Impairments, Disabilities and Handicaps, which was introduced "for trial purposes" (29), has been used increasingly in rehabilitation, in community surveys, and even in health insurance for assessment purposes. It has served as the basis for a major community survey in Spain and is officially used in France; it is also the classification used in the United Nations data base on disablement. The recent and current efforts of assess- ment of progress towards health for all have high- lighted, particularly in the European Region of WHO, the need for a classification tool which allows for comparison of data and trends. CHALLENGES AHEAD Tremendous developments have taken place in all facets of human life during the last 40 years. Health services have penetrated into rural areas and remote places. The health status of the population as measured by infant mortality rate, life expectancy and other key indicators has improved considerably. A wide range of new technologies is now in use in all countries -some highly complicated, some sophi- sticated but inexpensive, and some very ordinary but based on new concepts. The progress in health is being monitored, the deficiencies are being cor- rected, and the results are being evaluated and utilized in the subsequent planning and programming. Despite the impressive progress made, many health problems remain to be solved and some new ones have appeared. Epidemiology and statistics will have to contribute to the solution of these problems. The following are some of the challenges to WHO during the next decade. (1) Health information systems. WHO's role in technical cooperation with countries in this area should be to devise practical ways so that the most essential information is identified, less essential and unused data are weeded out, data processing and data flow are organized efficiently, and the information obtained is interpreted and used by relevant health personnel. Rapid progress in computer technology, especially microcomputers and hand-held computers, should facilitate this task. The guiding principles developed during the fourth decade should be refined on the basis of national experiences. Effective health information systems cannot be developed in a vacuum; they must parallel and closely link with improved managerial processes in which health decision- makers at all levels should be trained. As one of the fundamental data sources for health planning, vital statistics and civil registration should be promoted as a long-term target for countries where these are still deficient. (2) Cost-effectiveness of health action. Methods are now available to assess direct cause-effect re- lationships such as immunizations resulting in a reduction of incidence of a target disease. Methodo- logical development is still needed in situations involving a multitude of associated factors, such as finding out what beneficial health effects have resulted from improved water supply and sanitation. Evaluation of the cost-effectiveness of health mea- sures is all the more important as limited resources must be used to obtain maximum return. Applications of the risk approach focusing action on high-risk groups must be extended to deal with a wider range of health problems. More generally, resource allocations should be streamlined in order to improve the cost- effectiveness. Among the questions not yet answered is whether and to what extent the improvement in epidemiological and statistical information support has ultimately led to better health and well-being of people. (3) Health systems research. The above problems are examples of required health systems research in the wider sense of the term. Despite many years of attempts to develop research of this type, progress has been slow in the development of, for example, rel- evant epidemiological and statistical methods to sup- port it. One of the difficulties in finding the optimum organization of the health system in a country lies in the fact that the acceptability of a system is culture- bound and hence a universal model does not exist. (4) Health indicators. The target-oriented ap- proach to the development of indicators should be continued further. Even though health status indi- cators will proclaim the ultimate success or failure of health development, "process" indicators and indi- cators of associated factors are essential in health monitoring. As new factors affecting health are identified, appropriate indicators showing the level of such factors should be devised. These will include a group of "positive" health indicators, such as adequate nutrition, physical and mental performance, social adjustments, community participation and environmental protection. (5) Measurement and analysis of morbidity, dis- ability and mortality. Much of the morbidity, dis- ability and mortality occurring among children, young adults and middle-aged people throughout the world can be prevented by applying currently available 685 686 K. UEMURA health technologies, by taking appropriate socioeco- nomic measures, or by adopting a healthier life-style. More effective practical methods and procedures should be devised on the measurement and analysis of these negative aspects of health. Those on morbidity and disability require particular attention as they are not yet well developed. (6) International collaborative epidemiological studies. The results of this research based on uniform methodology are needed to find solutions to the com- mon problems confronting a number of countries. Available national resources can be used in most of these studies, with WHO as both the coordinator and a neutrally located data analysis centre. (7) ICD and related issues. The tenth revision of ICD will involve a considerable expansion of the current version (ICD-9), which should improve the recording, storage, analysis and use of detailed information on morbidity and mortality. At the same time, the classification ought to have a built-in capacity for easy aggregation, summarization and simplification so as to be applicable also to less com- plicated situations. The latter aspect should continue to be studied, and this will require concerted develop- mental efforts by countries. Classifications suitable for use in primary health care have to be developed, in collaboration with countries and relevant non- governmental bodies. Further work is also needed to improve the international classification of procedures in medicine and that of impairments, disabilities and handicaps. In addition, the development of appro- priate classifications of public health action, health personnel, and health expenditures is desirable for managerial purposes. REFERENCES 1. GEAR, H. S. ET AL. International work in health stat- istics, 1948-1958. Geneva, World Health Organ- ization, 1961. 2. SWAROOP, S. & UEMURA, K. Proportional mortality of 50 years and above. Bulletin of the World Health Organization, 17: 439-481 (1957). 3. PUFFER, R. R. & GRIFFITH, G. W. Patterns ofurban mortality: report of the Inter-American Investigation of Mortality. Washington, DC, Pan American Health Organization, 1967. 4. The accuracy and comparability of death statistics. WHO Chronicle, 21: 11-17 (1967). 5. KAGAN, A. ET AL. Atherosclerosis of the aorta and coronary arteries in five towns. 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