Host: S. Jay Olshansky, Ph.D., The University of Chicago
Funded by the National Institute on Aging and Center on Aging, University of Chicago
Summary
The health status of a population is inherently difficult to measure because it is often defined differently among individuals, populations, cultures, and even across time periods. The demographic measure of life expectancy has often been used as a measure of a nation's health status because it is defined by a single vital characteristic of individuals and populations -- death. However, the measure of life expectancy has limited utility as a gauge of a population's health status because it does not provide an estimate of how healthy the population is when it is alive.
The idea for the development of a measure of "health expectancy" (the partitioning of the demographic measure of life expectancy into healthy and non-healthy years of life) originated with a report published in 1969 by the U.S. Department of Health, Education and Welfare (HEW) (1969). The WHO report noted that both good health and long life are fundamental objectives of human activity, but that despite the substantial rise in life expectancy in the 20th century the overall health status of the population was unknown. In fact, it was recognized that accompanying the rise in life expectancy was the emergence of chronic diseases -- thus raising concerns about the future health status of the population if death rates continued to decline.
The first estimate of a population's health expectancy appeared in the 1969 HEW report, although the methodology upon which those estimates were based was not published until 1971 (Sullivan, 1971). Following the HEW publication, the OECD (1973) and World Health Organization (1974) published reports that recognized the importance of developing methods of measuring the health status of a population, noting that such indicators may help to determine the priorities and objectives of national health systems. The World Health Organization specifically recommended that person-years-of-life in health should be contrasted with total person-years-of-life in the standard measure of life expectancy. In 1984 a second report was published by a WHO scientific group recommending the further development of a life table based indicator of health status (WHO, 1984). In a 1985 report the WHO regional office for Europe included a measure of disability-free life expectancy (DFLE) as an optional regional indicator (WHO, 1985).
Under the coordination of Dr. Jean Marie Robine from INSERM in France, an international research network of scientists was formed in 1989 to address issues associated with the measurement and interpretation of measures of health expectancy. The organization, known as the Network on Health Expectancy or REVES (Reseau Esperance de Vie en Sante), was organized for the more specific purposes of 1) identifying the conditions necessary for comparing cross-national estimates of health expectancy, 2) examining issues relating to the interpretation of time series of health expectancies, 3) promoting the use of health expectancy measures for public policy and planning and for public health programs, and 4) to examine the possibilities for standardizing methods of data collection and calculation procedures for health expectancies. The Network on Health Expectancy is represented by scientists from a number of disciplines including demography, epidemiology, gerontology, sociology, health economics, medicine, biology, and statistics.
The first meeting of REVES was hosted by the Conseil des Affaires Sociales (CAS) of Quebec in September, 1989, and was attended by 48 participants from 9 countries and representatives of the WHO. The second workshop took place in Geneva, Switzerland in March, 1990, with a focus on international comparisons of healthy life expectancy. The principle development in the second workshop was an agreement on the health states to be used by scientists during the construction of the measure of health expectancy -- definitions of disability and handicap from the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) developed by WHO (1980). The third workshop, held in Durham, North Carolina in December, 1990, was focused on the methods of calculation and other methodological considerations associated with the measure of health expectancy. The theme of the fourth workshop in Leiden, The Netherlands in June, 1991, was on approaches to measuring changes in health expectancy in developed and developing countries. This was an important development for the Network because for the first time measures of health expectancy were presented for both developed and developing countries. This led to considerable discussion about cross-cultural variation in the definition of health and disability. The fifth workshop was held in Ottawa, Canada in February, 1992 with a theme of future uses of health expectancy indices. Most notable among the achievements at this meeting was the extension of the measure of health expectancy to specific causes of death, and a more thorough understanding of the limitations of the original Sullivan method of calculating health expectancy (Adams and Chamie, 1992). The sixth and final meeting of the original REVES series of workshops took place in Montpellier, France in October, 1992. This workshop was devoted to summarizing the previous three years of achievement in reaching consensus about the calculation and use of the measure of health expectancy, and to plan for the future of both the Network and the area of study.
At the REVES 6 meeting in Montpellier it was decided that a second series of workshops should be organized for the purpose of providing the opportunity to expand the Network and to begin exploring issues that were not addressed in the previous set of meetings. The locations of the three new workshops were decided at that time -- REVES 7 would take place in Canberra, Australia in the Winter of 1994 under the direction of Dr. Colin Mathers; REVES 8 would take place in Chicago, Illinois in the Fall of 1995 under the direction of Dr. S. Jay Olshansky; and REVES 9 would take place in Rome, Italy. Following is a brief summary of the REVES 8 meeting that was funded by the National Institute on Aging and the Center on Aging at the University of Chicago.
The REVES 8 meeting was held at the downtown Westin hotel in Chicago from October 5-7, 1995. The theme of the meeting was focused on the policy implications associated with measures of health expectancy. A total of 70 researchers representing 16 different countries attended the meeting. Eight of the participants (four students and four scientists from developing countries) were able to attend the meeting with funding provided by the National Institute on Aging. As a result, the network has expanded once again into parts of the developing world -- this time to include new data and analyses presented by scientists from the nations of Bulgaria, Fiji, India, Mexico, and Trinidad and Tobago.
On the first day of the conference sessions were held on the topics of Health Expectancy and Public Policy, Defining Health and Disability, Methodology, and Health Expectancy in Europe and North America. On the second day presentations were made in the area of Education, Income, and Health, Disease-Specific Approaches to Measuring Health Expectancy, and a second round of sessions on Methodology and Health Expectancy in Europe and North America. There was also some discussion on the second day regarding the development of a series of Web Pages about REVES and the researchers working in the field on the World Wide Web. On the third day sessions were held on the topics of Health Expectancy in Developing Nations, Limits to Lifespan and Life Expectancy, and Paths Between Health and Disease. There were 41 presentations made during the 2 1/2 day conference.
During REVES 8 some of the presentations were focused on revealing new health expectancy calculations for various nations made during the past 18 months since REVES 7 was held in Canberra, Australia. In general, for the developed nations there is evidence to suggest that during the decade of the 1980s, both life expectancy and healthy life expectancy increased at a faster pace than segments of the lifespan associated with frailty or disability. Some of the more important reasons given for these improvements were based on the hypothesis that recent cohorts of older persons are more highly educated than earlier cohorts examined, and that medical technology may be succeeding in reducing the frailty associated with selected diseases and disorders normally expressed at older ages. In developing nations the general picture of health expectancy was bleak -- with the data indicating without exception that recent cohorts of older persons in these nations have experienced declines in health expectancy. Problems associated with the delivery of health care, political problems affecting the availability of health care services, and a general focus on early age mortality at the expense of problems associated with aging, were the reasons given for these observed trends.
In addition to these new health expectancy calculations for selected nations, several researchers presented their latest work on recent advances in improving how health expectancy is measured. These included developments in the area of generating disease-specific approaches to measuring health expectancy, new methods of estimating health expectancy by socioeconomic status, and the first-time usage of micro-simulation techniques. Data were also presented on why the estimation of intrinsic mortality schedules may lead to a more complete understanding of temporal trends in life and health expectancy, and how the study of specific genes and the diseases associated with them may be useful in explaining observed characteristics of health and frailty in populations.
The plan at this time is to select 8-12 papers from among those presented and submit them to a journal for publication. Although the Journal of Aging and Health has expressed interest in devoting an entire issue to the papers presented at this meeting, the REVES steering committee is now considering alternative publication outlets. The steering committee also decided that the time has come to publish a new volume on health expectancy that will bring readers up-to-date on all of the developments associated with measuring, interpreting, and using health expectancy calculations. The purpose of this volume is an attempt at standardizing methods of analysis and avoiding the re-invention of concepts and statistical tools for measuring health expectancy by new scientists entering the field. It is our plan at this time to focus a portion of the REVES 9 meeting in Rome to the presentation of articles for this new comprehensive volume on health expectancy.
The REVES 8 conference was successful in bringing together scientists from many nations involved in the scientific analysis of issues associated with the increasing human longevity. The network of researchers working in this field was extended considerably by our ability to provide funding to scientists who would have otherwise been unable to attend the conference. Funding provided by the National Institute on Aging and the Center on Aging at the University of Chicago made it possible to hold a truly international meeting on this important issue of how the health of the population will be affected by increasing longevity. Both organizations will be gratefully acknowledged in any publications that result from this meeting.
References
Adams, O., Chamie, M. 1992. Future Uses of Health Expectancy Indices: General Report of the 5th Meeting of the International Network on Health Expectancy, Ottawa, February, 1992. REVES Paper No. 115.
OECD, 1973. List of Social Concerns Common to Most OECD Countries. Paris.
Sullivan, D.F. 1971. A Single Index of Mortality and Morbidity. HSMHA Health Reports 86:347-354.
U.S. Department of Health, Education and Welfare. 1969. "Towards a Social Report." Washington, D.C.: U.S. Government Printing Office.
World Health Organization, 1974. Modern Management Methods and the Organization of Health Services. Public Health Papers, p.55.
World Health Organization, 1980. International Classification of Impairments, Disabilities, and Handicaps: A Manual of Classification Relating to the Consequences of Disease. World Health Organization: Geneva.
World Health Organization, 1984. The Uses of Epidemiology in the Study of the Elderly: Reports of the WHO Scientific Group on the Epidemiology of Aging. Technical Report Series No. 706, Geneva.
World Health Organization, 1985. Targets for Health for All. In: Targets in Support of the European Regional Strategy for Health for All. Copenhagen.
.