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Together with fertility and migration, death is an essential determinant of population structure and growth. Geographers are interested in the role of mortality in population change; in the influences of environment on mortality (see health and health care, geography of); in the ways in which particular diseases are diffused (cf. diffusion); and in the relationship between mortality and economic and social conditions.
Mortality is measured in a number of ways. The simplest is the crude death rate, the number of deaths in a specific period per 1000 of the population. Like the crude birth rate (see fertility) this simple measure is severely distorted by age-structure variations which are obviously fundamental to determining overall mortality (see age and sex structure). Age-specific mortality rates express the number of deaths of persons of a certain age per 1000 of the population in that age group. In order to produce single-number indicators of mortality, standardized mortality rates may be calculated which take into account variations in age structure and make comparisons possible between regions or countries. Mortality rates may also be related to causes, which can be most informative about the incidence of disease in different age groups and different areas. life tables and the measures derived from them (e.g. life expectancy) provide the most detailed and sophisticated measures of mortality and are widely used in population models.
A most important group of measures relates to infant mortality, often given special attention because of its sensitivity to social and environmental conditions. The most frequently used infant mortality rate is the number of deaths of infants under one year old per 1000 live births in a given year. More precise measures include neonatal mortality, defined as those deaths occurring during the first four weeks of life, and post-neonatal mortality, those occurring within the remainder of the first year. There is also an important distinction in the causes of infant mortality between endogenous and exogenous mortality. The former refers to deaths from congenital malformations or delivery complications and the latter to deaths from infections or poor care. Improvements in modern medicine, health services, nutrition and maternal care have brought the most dramatic decline in infant mortality. General reductions in infant mortality are usually the first stage in overall mortality decline. In some underdeveloped countries and in past centuries in the presently developed world, infant mortality might account for 30 per cent or more of all deaths. In most developed states, the number is now very low: the graph shows the decline in infant mortality in Finland from 1750-1990.
The decline in general mortality levels in the developed world has been fairly constant during the twentieth century, with the result that fertility has generally been more important than mortality in determining short-term fluctuations in population. In the developing world, however, mortality has often been reduced dramatically over a few years, producing very rapid population growth. Mortality decline is an essential element in the demographic transition model. Ascribing causes to mortality decline is not as simple as it may seem. Many of the worst diseases have certainly either disappeared or been greatly reduced, and famine and subsistence crises are now less influential as the world\'s social and economic environment has improved. Causes of death have changed dramatically (Mercer, 1990): plague, smallpox, cholera and tuberculosis are not the killers they once were and in developed countries mortality is now associated more with cancer, heart disease and road accidents. Nevertheless, mortality may still surprise, as the geography of AIDS has demonstrated in both the developed and the developing worlds (Gould, 1993; see AIDS, geography of).
The major argument about causes of the general decline in mortality centres around the conflict between the role of medicine and the general improvements in standards of living. Techniques of diagnosis and surgery, inoculation and the development of drugs were undoubtedly influential, but more so in recent decades in the Third World than in nineteenth- and early twentieth-century Europe. For it has been shown that general increases in living standards — improvements in the quantity and quality of food, better sanitation, hygiene and housing conditions — were just as important as changes in medical care. Research has also concentrated on the varying susceptibility of sections of the population to disease and death: differential mortality rates may be calculated to show the influence of racial or ethnic background, education, income and social or occupational status, sex and rural or urban residence. (See also medical geography.) (PEO)
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mortality Infant mortalityin Finland, 1750-1990 (Rallu and Blum, 1991)
References Gould, P. 1993: The slow plague: a geography of the AIDS pandemic. Oxford: Blackwell. Mercer, A, 1990: Disease, mortality and population in transition. Leicester: Leicester University Press. Rallu, J.-L. and Blum, A., eds, 1991: European population. I. Country analysis. London: John Libbey, 153.
Suggested Reading Cliff, A. and Haggett, P. 1992: Atlas of disease distributions. Oxford: Blackwell. Cliff, A., Haggett, P. and Smallman-Raynor, M. 1993: Measles. An historical geography of a major human viral disease. From global expansion to local retreat 1840-1990. Oxford: Blackwell. Daugherty, H.G. and Kammeyer, K.C.W. 1995: An introduction to population, 2nd edn. New York and London: Guilford Press, ch. 7. Howe, G.M. 1976: Man, environment and disease in Britain; a medical geography of Britain through the ages. London: Penguin; New York: Barnes and Noble. Jones, H.R. 1990: Population geography, 2nd edn. London: Paul Chapman. Livi-Bacci, M. 1997: A concise history of world population, 2nd edn. Oxford: Blackwell. Lopez, A.D., Caselli, G. and Valkonen, T., eds, 1995: Adult mortality in developed countries: from description to explanation. Oxford: Clarendon Press. Lutz, W., ed., 1990: Future demographic trends in Europe and North America. London: Academic Press, part 1. McKeown, T. 1976: The modern rise of population. London: Edward Arnold; New York: Academic Press. Schofield, R.S., Reher, D.R. and Bideau, A., eds, 1991: The decline of mortality in Europe. Oxford: Clarendon Press. Woods, R.I. 1979: Population analysis in geography. London and New York: Longman. |
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