The two core values on which the work of the Pan American Health Organization (PAHO) revolves are equity and Pan Americanism. These values form the basis for cooperation with countries, and measuring and monitoring inequalities are therefore fundamental activities for decision-making. Technical cooperation with countries should focus on the identification of inequities and on the formulation of effective strategies for reducing and, ultimately, eliminating them.

Although important gains have been made in the overall health situation in the Region, the Americas remains the region with the greatest inequity in income distribution in the world. There are still large disparities in health status between different countries and social groups. It is known that groups with lower socioeconomic status not only suffer a greater burden of disease, but, in addition, they tend to develop chronic diseases and disabilities at earlier ages; they have less access to health services, and the services they do receive are of poor quality.

The measurement of health inequalities is an indispensable condition for moving forward in the effort to improve the health situation in the Region, where the analysis of average values is no longer sufficient. This type of analysis is a key tool for action aimed at achieving greater equity in health. In general, health information systems and health situation analyses do not include evaluation of inequalities. Measuring inequalities in health and living conditions constitutes the first step toward the identification of inequity in the field of health. According to Whitehead (1991) and Schneider (2002), inequality is not synonymous with inequity. Inequity is an unfair and avoidable inequality, and therein lies its importance for decision-makers. Classifying an inequality as inequity implies knowing its causes and being able to substantiate a judgment as to the unfairness of those causes.

In light of the importance of the matter, this issue of the Epidemiological Bulletin presents a summary of the special issue on measuring health inequalities published by the Pan American Journal of Public Health in December 2002 (Vol. 12, No. 6). In addition, it revisits one of the articles, Methods for Measuring Inequalities in Health, by Schneider et al., which presents a simple explanation of the various methodologies for examining health inequalities. The article by Schneider et al. provides a guide for calculating indicators and discusses the advantages and disadvantages of each of them. This issue of the Epidemiological Bulletin includes a summary of the introduction and the type of indicators and their characteristics; subsequent issues will present the methodology for calculating the indicators most frequently used to measure inequalities in the field of health, including rate ratio and rate difference, effect index, population attributable risk, index of dissimilarity, slope index of inequality and relative index of inequality, Gini coefficient, and concentration index.

Outline of the Inequality Journal of Health

Inequities in health are the differences in the levels of health among distinct socioeconomics groups that are considered unfair, on the basis of a detailed judgment of their causes.1 Similarly, Kawachi, Subramanian & Almeida-Filho2 define inequities in health as the inequalities in health that are considered unfair or stemming from some form of injustice. Common to the different published definitions of inequities in health, is the underlying assumption of injustice.3 Then, to evaluate inequities in health, there is the need for making possible the measurement of fairness in a given society. Although some methodologies have been proposed, all are based in a necessary judgment of value and are dependent of the adopted theory of justice and the accepted explanations for the etiology of the observed inequalities, involving therefore a political conception.2,3 Consequently, the International Society for Equity in Health adopts, as operational definition, that inequities are “systematic [and potentially remediable] differences in one or more aspects of health status across socially, economically, demographically or geographically defined populations or population sub-groups”.4 A readily measurable dimension of this concept, that has allowed an approach of the iniquities in health in a society, is that of inequalities in health. These are understood as a generic term that involves population differences, variations and disparities in the health achievements of individuals and groups that need not imply moral judgment of these differentials, nor strict considerations on their remediation.2

Recently, a great interest in the subject of inequities and inequalities in health has been noticed. Several studies have pointed out the important magnitude of health inequalities in countries with varying degrees of development. In addition, and more disturbing, is that regardless of a general improvement of the average population health conditions, an increasing trend of health inequalities occurred in recent years in many regions. The importance of health policies as instruments to correct and decrease those inequalities in highlighted each time more frequently; however, when existing inequalities are ignored, policies may influence the health sector in such a way that the sector could actually constitute another determinant of the amplification of health inequalities in a society. In this regard, the concept of equity in health services must also be mentioned, which implies that there should be no differences in health services where health needs are equal (horizontal equity) or that improved health services be provided where greater health needs are present (vertical equity).5 Obviously, the issue of inequalities in health and their marked socio-economic determination is not a subject that only concerns the health sector, both with respect to its conceptual frame, as well as from the perspective of the identification and development of effective interventions for their solution. Due to the variety of determinant factors involved in the causal net of health inequalities, a muti-sectoral approach, with policies, programs and interventions leading to reduce or limit the negatives effects on health, are required.

The subject of the inequalities in health has been an important object of attention of the Pan American Health Organization (PAHO) at a right time, integrating the concept in its mission for strengthening the use and analysis of information on inequalities for public health management in the Americas. In addition, several initiatives to stimulate the theoretical-conceptual debate on this subject have been adopted and a great effort devoted to promote the institutionalization of evidence-based practices that aim equity in health among population groups of our societies. Among these practices, the need for monitoring and surveillance of health inequalities and the assessment of their etiology, which frequently show important local specificities, are highlighted. Accordingly, PAHO has made available technical information, methodologies and other materials to facilitate the approach of health inequalities within the practice of the health services, and for the sensitization of the health professionals, in particular decision makers, regarding this theme.

One of PAHO’s recent specific initiatives in this direction has been the publication of a special issue of the Pan American Journal of Public Health on “Measuring Health Inequalities” that was distributed in December of 2002. This issue included six original articles and three current topics. Moreover, it contained a special guideline on “Methodologies for measurement of health inequalities”. The following section presents a brief commented summary of these articles.

The articles by Barbosa, J. & Barros, M.B. [“Epidemiologia e desigualdades: notas sobre a teoria e a história” – article in portuguese] and by Starfield, B. [“Equity in health: perspective on non-random distribution of health in the population” - current topic in english] present a conceptual historical framework on the subject. Barbosa & Barros introduce the history of the precursory thoughts that lead to the current conceptualization of the health inequities that is amply discussed on the basis of a relevant bibliographic review. The article includes historical explanations of disease causation in human populations and its inherent health inequalities, as well as the development of the role of Epidemiology in this context. The article by Starfield, starts indicating that heath inequalities do not occur randomly, and discusses the determinations of clustering of health-related problems identified in human populations. The author proposes a complex net of causality of health states and determinant risk factors that serves as the basis for understanding that health events aggregate in a systematic way (and not at random). She also points out that it is very unlikely that this complex causal net acts in the same way in all areas/regions and calls the attention on the need for further studies on the genesis of health inequalities. She concludes suggesting that the information and knowledge originated from such studies be translated into effective actions for problem solving.

Another article adds a reflection on the situation of inequalities in health in the Americas, including examples of different methodological approaches used for their measurement, presented by Alleyne, G.A.O, et al. [“Overview of social health inequalities in the region of the americas using different methodological approaches” - article in english]. In this work the authors carry out a descriptive analysis of the health situation in the region of the Americas, followed by an exploratory approach of the social inequalities in health among countries in this Region. Highlighting the great disparities in health status and in some of their determinants, the authors indicate that the search for equity in health is not only a theoretical matter, but a concrete reference for technical cooperation among countries, once that equity is recognized as an imperative assumption required to achieve an integral human development in the Region.

As examples of analyses of health inequalities in countries of the Americas, the journal includes the articles by Duarte, E.C., Et al. [“Expectativa de vida ao nascer e mortalidade no brasil em 1999: uma análise exploratória dos diferenciais regionais” – article in portuguese] and Gattini, C; Sanderson, C. & Castillo-salgado, C. [“Variaciones de indicadores de mortalidad evitable como aproximación a desigualdades en salud en comunas chilenas” – article in spanish]. In the work carried out in Brazil (Duarte et al), the inequalities in health among the Brazilian regions and states were studied, with emphasis on life expectancy at birth, infant mortality and child mortality (children less than 5 years of age) according to specific causes (diarrheal and acute respiratory diseases), and mortality rates due to external causes (homicides and traffic accidents). Ecological associations between the selected health indicators and socio-economic and demographic indicators were analyzed. The study results indicated a pattern of health inequalities in Brazil with a marked intra-national and intra-regional polarization, as well as juxtaposition of diseases related to both underdevelopment and development. This complex situation demands more specific actions from the health sector aiming to minimize these inequalities. The article by Gattini, Sanderson and Castillo-Salgado analyzes the variation of preventable mortality indicators, as an approach to assess the magnitude of health inequalities, among distinct geographical areas. They used for this methodological approach, health data from small geographic areas in Chile. The authors observed significant inverse (negative) associations between preventable mortality indicators (potential years of life lost, preventable mortality rates and infant mortality rates) with those of socio-economic development and discussed the implications of their findings for policies on prioritization to those areas with the worst situation and on increased coverage to prevent the highest number of deaths.

The special issue of the journal includes, in addition, some useful methodological experiences for the study of health inequalities that are described as follows.

In the article on ‘methodologies for the measurement of health inequalities’ [Schneider, MC et al. “Metodologias para la medición de desigualdades en salud”– report in spanish] the authors discuss appropriate indicators of health situation, health services and socio-economic status for studies on health inequalities. In addition, they describe selected basic methodologies for measuring health inequalities, which may be useful for the health services settings at their various levels. The circumstances and levels of application as well as advantages and limitations of the different measurement methods are also discussed.

Using a theoretical and practical approach, Bacallao, J. Et al [“Indicadores basados en la noción de entropía para la medición de las desigualdades sociales en salud” – current topic in spanish], describe the advantages for measuring inequalities based on the notion of entropy. This concept has its origin in the Physics, the Statistics and the Information Theory. In this article, the authors started with a review of the classic indicators used for measurement of health inequalities, and then describe the indices based on the notion of entropy. Regarding this last aspect, the definitions and the properties of such indices are discussed and examples of their use for measuring health inequalities included. The authors’ conclusions are in favor of the usefulness of these indices in the field of inequalities, considering that some of their properties are unique to this end.

The article by Metzger, X [“Agregación de datos en la medición de desigualdades e inequidades en la salud de las poblaciones” – article in spanish] had as its objective to determine the consequences and adequacy of using different levels of data aggregation for measuring of inequalities in the health situation of populations. The author exemplified the calculation of the most frequently used measures, having the infant mortality rate from Costa Rica as health indicator. Metzger discusses the need for considering the benefit vs. loss trade-off when opting between a higher or a lower level of aggregation of geographical units used in health inequality studies. With the Costa Rica example, the effects on the consistency of results obtained from studies that use larger aggregates are described. The author concludes that some measures generate important result discrepancies according to the different levels of aggregation utilized and recommends considering the study objectives to guide an adequate selection of methodologies to be used.

In another article, Loyola-Elizondo E., Et al. [“Los sistemas de información geográfica (sig) como herramienta para el monitoreo de las desigualdades en salud” – article in spanish], discuss the usefulness of Geographic Information Systems (GIS) for monitoring health inequalities, highlighting their capability for data and information integration from different sources and types and their subsequent processing. This allows simplifying, improving speed and automation of epidemiological analyses at diverse levels of aggregation. To illustrate the properties of GIS, the authors used as example the inequalities on the infant mortality rates (because it is one of the indicators with broadest coverage) in the countries of the region of the Americas, according to socio-economic indicators, analyzed in three different levels of aggregation (regional, national and local). They conclude that, based on the definition of the magnitude and distribution of health events and their determinants, the adequate use of GIS in the study of health inequalities contributes to facilitate public health management. In addition, GIS enables focalizing and planning of interventions in the high priority areas and groups, among other applications.

The compilation of these articles in the special issue of the Pan American Journal of Public Health constitutes a useful instrument to initiate the debate on the need to include the subject of health inequalities in the agenda of decision makers in the health sector.

References:
(1) Kunst AE & Mackenbach JP. Measuring socioeconomic inequalities in health. Copenhagen: WHO Regional Office for Europe, 1994. 115 p.
(2) Kawachi I, Subramanian SV & Almeida-Filho N. A glossary for health inequalities. J. Epidemiol Community Health. 2002; 56:647-652.
(3) Macinko J & Starfield B. Annotated Bibliography on Equity in Health, 1980-2001. International Journal for Equity in Health. 2002; 1(1).
(4) International Society for Equity in Health. The Toronto Declaration on Equity in Heath. Conference Statement: 2nd International Conference. Toronto, June 2002.
(5) Starfield B. Improving equity in health: A research agenda. International Journal of Health Services. 2001; 31(3):545-566.

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Epidemiological Bulletin , Vol. 25 No. 4, December 2004