The Changing Context of the Transition in sub-Saharan Africa
Researchers have long recognized the value of epidemiology and demography—and the interplay between them—in analyzing trends in mortality changes and have, conversely, recognized the role that health plays as both cause and consequence of various demographic and socioeconomic changes. In particular, the concepts of demographic, epidemiological, and health transitions have proved quite valuable in the study of population changes in countries throughout the developed world. Thus it is not surprising that most of the studies of population trends in the developing world have also relied upon these concepts, even though their usefulness in understanding population trends in developing countries has been repeatedly called into question. The issue is particularly relevant for the study of health trends in sub-Saharan Africa, as the history and experience there differs substantially from that of Western Europe and North America, for which the concepts were originally developed. Thus it is important to ask whether these frameworks are the most suitable for studies of sub-Saharan Africa.
The purpose of the workshop’s first presentation was to describe the major challenges to human health in Africa within the context of a comparative cross-national research framework. Kuate Defo provided descriptions and explanations of epidemiological change in Africa over the last 60 years, and he discussed three frameworks for analyzing changing patterns of population health and mortality: the demographic transition, the epidemiological transition, and the health transition frameworks. He also described a detailed analysis of trends in health, disease, and mortality in African regions and countries from 1950 to 2010; the analysis was based on existing literature and time-series data on mortality statistics and characteristics involving 55 African countries derived from databases of major international organizations.1
Defo presented some relatively simple methods for analyzing changes and developing quantitative indicators to test how well the demographic transition, epidemiological transition, and health transition frameworks apply to the patterns seen in Africa over the past half dozen decades. Both theoretical criticisms and empirical
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1These databases include the United Nations World Population Prospects 2010, available at http://esa.un.org/unpd/wpp/unpp/p2k0data.asp; the World Bank Africa Development Indicators 2011, available at http://data.worldbank.org/sites/default/files/adi_2011-web.pdf; the WHO/UNICEF 2012 Immunization Summary, available at: http://www.who.int/immunization_monitoring/data/en/; World Health Organization estimates, available at http://www.who.int/research/en/; International Labour Organization statistics, available at http://www.ilo.org/stat/lang--en/index.htm; and data from the United Nations Educational, Scientific and Cultural Organization Institute for Statistics, available at http://stats.uis.unesco.org/unesco/tableviewer/document.aspx?ReportId=143.
evidence indicate that these frameworks have a number of limitations in describing and explaining trends in demographic and health trajectories in Africa.
In light of these limitations, Defo proposed a new conceptual framework for analyzing African countries, one that he calls an “eco-epidemiologic life-course framework” for understanding the patterns of health and disease in human populations. Defo’s analysis of 60 years of data indicates that Africa is a continent of uncertainties and emergencies where trends in health, disease, and mortality are marked by discontinuities and abrupt changes that reflect the enduring fragility and instability of its countries and the vulnerabilities of its individuals and populations. The analysis also shows that Africa as a whole—and sub-Saharan Africa in particular—remains the poorest of the world’s regions in terms of health improvements and longevity. Specifically, the research demonstrates: (1) a marked variation in trends in health, disease, and mortality patterns as well as in fertility and life-expectancy trajectories among African countries and regions over the past 60 years; (2) a rapid decline in mortality—specifically, declines in infant mortality and increases in life expectancy—throughout the continent from the 1950s through the 1990s, a period during which communicable diseases were responsible for most deaths in Africa; (3) growing rates of adult mortality since the 1990s, which have been mostly ascribed to HIV/AIDS and its comorbidities and which have played a major role in reversing the trend of declining mortality, interrupting improvements in life expectancy, and reversing gender differences in life expectancies in several countries with highest prevalence of HIV/AIDS because of the disease’s disproportionate impact on women; and (4) the major role that wars have played in reversing the trends in underfive mortality decline in sub-Saharan countries in the 1990s and beyond, notably in middle Africa and Eastern Africa.