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MECHANISMS OF AGEING AND DEVELOPMENT. 1991 Jan; 57(1):25-48.Demographic data published by the UN in 1987 are analyzed in terms of the Gompertz function. Projections for maximum lifespans are obtained, with the data broadly divisible into 3 clusters. These are attributable not only to the influence of high infant mortality, but suggest constitutional and/or environmental variations among members of the clusters. The difference between lifespan and life expectancy is estimated analytically. A comparison with earlier analysis supports the view that there are important differences between the life expectancies of the sexes.
World Health Statistics Quarterly. Rapport Trimestriel de Statistiques Sanitaires Mondiales. 1985; 38(3):302-16.Tables present data on the prevalence of anemia in the world. Anemia may be defined as a state in which the quantity or the quality of circulating red cells is reduced below the normal level. The most common way to diagnose anemia is by measuring the hemoglobin concentration in the blood which is controlled by a homeostatic mechanism. It varies slightly among normal subjects. In 1959, the World Health Organization (WHO) proposed levels of hemoglobin concentrations for different groups of individuals that could be considered as the lower limits of normality. Subjects with values below these levels were considered to be anemic. The causes of anemia, which are multiple, include a deficiency of hemopoietic factos, genetic disorders causing hemolytic anemias, infections including malaria, and increased losses of blood caused inter alia by infections such as ankylostomiasis or schistosomiasis. A survey of the prevalence of anemia in women in developing countries was published by WHO in 1982. It estimated the prevalence of nutritional anemia in developing countries (other than China) at 60% in pregnant women and 47% in non-pregnant women. The prevalence of anemia in all women of reproductive age was estimated at 49%. It appears that studies on the prevalence of anemia were conducted regularly during the 1960-84 period, with the exception of studies on elderly people most of which were conducted before 1970. Most studies included from 100 to 300 subjects. Studies on adolescents usually covered fewer than 100 subjects. The tables provide no data on the severity of anemia, i.e., the percentage of subjects with a hemoglobin concentration below a specific level. On the basis of the present review, the total prevalence of anemia in the world is most likely about 30%. Expressed in absolute numbers this means some 1300 million people of the estimated world population of 4440 million in 1980. For the developing regions of the world, the prevalence of anemia is probably about 36% or 1200 million people, and for the more developed regions about 8% or just under 100 million people. Young children and pregnant women are the most affected groups with an estimated global prevalence of 43% and 51%, respectively. The regions with the highest overall prevalence of anemia are South Asia and Africa. With the exception of pregnant women, the prospects for the prevention of iron deficiency anemia in a population are poor at the present time. Iron fortification and the daily administration of an iron supplement present great problems in developing countries, and they will not be resolved easily.
In: Population prospects in developing countries: structure and dynamics, edited by Atsushi Otomo, Haruo Sagaza, and Yasuko Hayase. Tokyo, Japan, Institute of Developing Economies, 1985. 115-40, 329. (I.D.E. Statistical Data Series No. 46)This paper reviews the various methods of projecting future numbers of households, summarizes prospective major trends in the numbers of households and the average household size among the developing countries prepared by the UN Population Division in 1981, and analyzes the size structure of households among the developing countries in contrast to the developed nations. The purpose of this analysis is to prepare household projections by size (average number of persons in a household) for the developing countries. The headship rate method is now the most widely used procedure for projecting households. The headship rate denotes a ratio of the number of heads of households, classified by sex, age, and other demographic characteristics such as marital status, to the corresponding classes of population. When population projections have become available by sex, age, and other characteristics, the projected number of households is obtained by adding up over all classes the product of projected population and projected headship rate. In addition to the headship rate method, this paper also reviews other approaches, namely, simple household-to-population ratio method; life-table method, namely the Brown-Glass-Davidson models; vital statistics method by Illing; and projections by simulation. Experience indicates that the effect of changes in population by sex and age is usually the most important determinant of the change in the number of households and it would be wasteful if the household projections failed to employ readily population projections. Future changes in the number of households among the developing countries are very significant. According to the 1981 UN projections, the future increase in the number of households both in the developed and developing countries will far exceed that in population. In 1975-80 the annual average growth rate of households was 2.89% for the developing countries as a whole while that for population was 2.08%. In 1980-85, the growth rate for households for the developing countries will be 2.99%, while that for population will be 2.04%. In 1995-2000 the figure for household growth will be 2.89%, whereas that for population will be 1.77%. The past trend of fertility is the most important factor for the reduction of household size and it would continuously be the central factor. The increasing headship rates will be observed among the sex-age groups, except the young female groups, as a result of increasing nuclearization in households.
In: United Nations. Department of International Economic and Social Affairs. Population projections: methodology of the United Nations. New York, N.Y., United Nations, 1984. 60-6. (Population Studies, No. 83; ST/ESA/SER.A/83)This paper offers suggestions for guiding the next projection's exercise at the United Nations in light of third world life tables which, although severely limited, are believed to be relatively reliable. Of prime importance is the suggestion that expectation of life at birth in a number of less developed areas has begun to overtake and surpass the lower levels of such measures among the populations of developed countries. Although this is the 1st such occurrence on record, it is not likely to be reversed. A major implication of these patterns is that the causal linkages which have historically connected levels and patterns of socioeconomic development with those of mortality have become greatly attenuated. It is safe to say that major new causal mechanisms for reducing mortality have come into play which demographers have yet to comprehend adequately for purposes of projection. Another suggestion is to increase attention to the specific status and performance of national public-sector health programs (including water supply and sanitation) key factors affecting the onset and scale of mortality downtrends during the postwar decades. In addition, increasingly close attention needs to be paid to political disturbances, affecting health-care programs financing and associated delivery systems. With few exceptions, differences between female and male life expectancies at birth have been rising in the sample areas under review, implying that the gains over time for females have been higher than those for males. This directional pattern at both ages is remarkably similar to what has been found to hold with notable consistency among developed countries since 1920. Its prevalence suggests a bench-mark for checing the projected longevity differentials between males and females in the next UN exercise; at a minimum, these should be compared with past directions and magnitudes of change. Added or new attention should be given to comparisons between developed country and less developed country mortality measures; to how such measures vary by age at given points of time and shift by age over time; to sex differentials of both mortality levels and changes; and to the rapidly growing stocks of information becoming available on leading correlates of deaths, survival and morbidity rates. Such attention will enhance the quality, relevance and reliability of the future work of the UN on population projections.
Revue Tiers Monde. 1983 Apr-Jun; 24(94):305-24.This article discusses methodologies for arriving at population projections and predictions and their limitations, and presents short-term predictions for 1980-2000, longterm projections for 2000-2025, and very longterm projections for 2025-2100, which are highly speculative. The UN population projections for 210 countries and territories are provided by age and sex and by rural or urban status. The UN projections are prepared in 3 phases: 1) analysis of the quality of the basic data in different regions; 2) development of hypotheses concerning the evolution of fertility, mortality, and migration; and 3) separate projection of each component of growth. 4 variants, the medium, high, low, and constant fertility versions are usually prepared, of which the medium projection is considered most likely and that of constant fertility is included only for comparisons. The world crude reproduction rate fell from 2.41 in 1950 to 1.96 in 1975-80, and is expected to fall to 1.34 during 2000-2010 and to almost unity in the mid 21st century. Only Africa and Latin America are expected to have crude reproduction rates above replacement level in 2025. According to the medium projection, the world population will each 6.2 billion in 2000 and 10.4 billion in 2075, when it will be nearly stationary. Future growth in already developed countries will be minimal, but Third World countries, which had a population of 1.7 billion in 1950 and 3.3 billion in 1980, will have nearly 5 billion by 2000 and will stabilize at about 9.1 billion, representing 87% of total world population. About 40% will live in South Asia. The population in 2075 will be 1.2 billion in Latin America, 2.2 billion in Africa, and 1.7 billion in East Asia. The age structure of the future population will undergo considerable aging and the trend toward urbanization will accelerate.