Rationalizing health care in a changing world: the need to know *

The World Development Report 1993 announced that global life expectancy was then 65. Experience in the developed world suggests that the World Health Organization’s dictum, ‘health is a state of complete physical, mental and social well-being’, is simply not attainable for the foreseeable future. As physical health has improved, mental problems have become more prominent and a sense of well-being has declined. Furthermore, as the population ages and medical technology improves, the cost of health care grows almost exponentially. Since the population of the developed world is continuing to age and aging is spreading rapidly throughout the developing world, knowledge is the principal way of dealing with this seemingly intractable problem: we must know, quantitatively, the age-specific causes of ill health, and we must know which means of prevention and treatment are effective. Finally, we must apply that knowledge rationally The first childhood of humankind essentially began when primates descended from the trees millions of years ago; it lasted until about the end of the nineteenth century when life expectancy began to rise in the Western world. It began to accelerate only about 50 years ago and touched the developing world only in the last 30 years. Richard Peto found that half the population was dead before the age of 40 in the pre-agricultural Palaeolithic and agricultural Neolithic periods, in a Roman colony in North Africa, in old rural Britain (pre-industrial revolution) and in tropical Africa only a short time ago (R. Peto, personal communication). A Rockefeller Foundation meeting in 1985 called Good Health at Low Cost made us aware tha