Book Review

The Burden of Disease Among the Global Poor: Current Situation, Future Trends, and Implications for Strategy

This new World Bank publication commences with a discussion of the importance of information on the burden of disease that is specific to the poor. It takes the position that the recent identification of the rapidly increasing non-communicable disease (NCD) burden in the "global" population lacks "congruity" in that "the poor" (in all settings) are more liable to be affected by communicable diseases than are "the rich."

To address this deficiency, the authors compare disease burden among the 20% of the global population living in countries with the lowest per capita incomes, with similar estimates for the 20% living in countries with the highest per capita incomes. They conclude that 59% of deaths and disabilities "among the poorest 20%" are due to communicable diseases, whereas 85% among the world's "richest" are due to NCDs. Then they analyze the implications of disease reduction strategies during the 1990-2020 period for the world's poorest and richest 20%. They conclude that a fast decline in communicable diseases would decrease the poor-rich gap by 2020, but an accelerated rate of overall decline in NCDs would actually widen the gap. The authors close with sections dealing with interpretations and implications for strategy.

The work is said to have been conducted to help guide the World Bank's recent health policy, which gives highest priority to improvements in the health, nutrition and population status of the world's poor. While the authors acknowledge some conceptual and methodological problems, the fact that it comes out under the authority of the World Bank requires not only that we must pay attention to it, but also that we must subject it to critical standards of review.

The impetus for the publication was the study on the global burden of disease edited by Murray and Lopez, which concluded that by 1990 NCDs had overtaken communicable diseases as the leading cause of mortality worldwide (56% of all deaths, not including injuries which then accounted for 10%, the remaining 34% attributable to communicable diseases). By the year 2020, NCDs were projected to account for 73% of global mortality, with communicable diseases declining to 15%. This analysis of trends, incorporating the same DALYs methodology used in the publication under review, has been widely disseminated.¹

In essence, Gwatkin and Guillot offer an aggregate comparison of the world's poorest countries with the world's richest countries. While the language throughout refers to "the poorest 20%" and "the richest 20%", the reader must remain alert to the fact that this refers not to people but to countries. The countries are not listed, but one assumes that we are comparing the likes of Rwanda, Haiti and Afghanistan with countries such as Japan, Switzerland and the United States.

Nowhere is the situation within countries actually examined, so that the approach must entail a major risk of ecological fallacy (defined in the dictionary of the International Epidemiological Association as "the bias that may occur because an association observed between variables on an aggregate level does not necessarily represent the association that exists at the individual level"²). This bias is compounded by an analysis (based on lower and upper quintiles) that effectively excludes 60% of the world's population (the second to fourth quintiles), most of whom live in developing countries.

The authors view the emergence of NCDs in less developed countries as a function primarily of population aging and of progress against communicable disease in infants and children. While these are indeed powerful forces, there is no recognition here of the power of globalization that is forcing rural-urban shifts and associated trends in determinants which, in turn, are driving epidemiologic transitions. The poor are less able to resist the negative consequences of these trends. In terms of solutions, there is no apparent recognition of life cycle, family centred or community-based approaches to prevention, nor of the potential to develop cost-effective approaches (including non-pharmacological) within integrated systems of primary health care.

In support of their interpretation of prevention and cost-effectiveness issues, the authors rely heavily on the highly respected textbook Disease Control Priorities in Developing Countries, published  for the World Bank in 1993.³ The reviewer would refer to this also for certain purposes, but in terms of a fair comparison between communicable diseases as a whole versus NCDs as a whole, it is notable that the emphasis is on primary prevention for the former, with relatively more emphasis on secondary prevention and palliation for the latter. Therefore, it should not be surprising that an aggregate analysis ends up favouring communicable disease interventions generally over those for NCDs.

Arguably, addressing the root causes of poverty itself would do far more for the health of the global poor— whether or not they are now suffering from communicable or non-communicable diseases (and they are suffering from both)—than encouraging the view that to address the emergence of non-communicable diseases at this stage is not appropriate. Dividing the decision framework into communicable and NCDs is simplistic, and may even be a legacy of traditional medical thinking.

Instead, why does the World Bank not base its decisions on an assessment of disease burden, prevention effectiveness and cost-effectiveness of particular interventions, regardless of whether something is or is not communicable? Measures such as tobacco control, improved diet and physical fitness, education about care seeking and even promoting quality of care where service is already being provided are actually quite feasible in many developing countries. However, these approaches to NCDs are not well recognized in the document or its sources. For example, injury prevention is one of the most cost-effective opportunities for reducing disease burden across all income groups in all countries, and one in which the Bank has invested virtually nothing to date.

The role of the World Bank in international health has been increasing over the past decade, even eclipsing that of the World Health Organization in many respects, and the need for its participation in health policy development is undeniable. However, this publication, in which communicable diseases and NCDs are juxtaposed as if this is a dichotomous choice that has to be made in developing countries, is contentious and has little do with what is actually happening on the ground.

When people lose their health in an urban squatter community or in a poor rural village, should we differentiate their priority in terms of whether the condition is communicable or non-communicable? After all, within each category there are examples of interventions that are cost-effective and of others that are not. While the authors fill an important gap in the debate with this document, clearly it is a debate that must go on, as this analysis also lacks "congruity". Equally, the literature on prevention effectiveness generally needs to be more fully developed, taking into account a wider range of possible solutions.

In conclusion, this World Bank publication is an important contribution to the field of international health, not only because of its radical approach to analyzing the challenge of the "double burden" of disease that confronts developing countries, but also because it comes from an institution that is enormously influential on policy makers, especially those who are associated with international aid agencies. I would recommend that it become required reading in all graduate programs in the field of public health, in view of the inevitable debate that it should generate, not only in terms of its methodology but also in terms of the strengths and limitations of its analysis, interpretations and conclusions.

References

1. Murray CJL, Lopez AD, editors. The global burden of disease — summary. Cambridge (MA): Harvard School of Public Health (on behalf of the World Health Organization and the World Bank), 1996.

2. Last JM, editor. A dictionary of epidemiology. 3^rd edition. New York: Oxford University Press (for the International Epidemiological Association), 1995.

3. Jamison DT, Mosley WH, Measham AR, Bobadilla JL, editors. Disease control priorities in developing countries. Oxford University Press (for the World Bank), 1993.

Franklin White
Professor and Chair
Community Health Sciences
The Aga Khan University
Karachi, PAKISTAN

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