Global health is fashionable. It provokes a great deal of media, student, and faculty interest, has driven the establishment or restructuring of several academic programmes, is supported by governments as a crucial component of foreign policy,1 and has become a major philanthropic target. Global health is derived from public health and international health, which, in turn, evolved from hygiene and tropical medicine. However, although frequently referenced, global health is rarely defined. When it is, the definition varies greatly and is often little more than a rephrasing of a common definition of public health or a politically correct updating of international health. Therefore, how should global health be defined?
Global health can be thought of as a notion (the current state of global health), an objective (a world of healthy people, a condition of global health), or a mix of scholarship, research, and practice (with many questions, issues, skills, and competencies). The need for a commonly used and accepted definition extends beyond semantics. Without an established definition, a shorthand term such as global health might obscure important differences in philosophy, strategies, and priorities for action between physicians, researchers, funders, the media, and the general public. Perhaps most importantly, if we do not clearly define what we mean by global health, we cannot possibly reach agreement about what we are trying to achieve, the approaches we must take, the skills that are needed, and the ways that we should use resources. In this Viewpoint, we present the reasoning behind the definition of global health, as agreed by a panel of multidisciplinary and international colleagues.
Public health in the modern sense emerged in the mid-19th century in several countries (England, continental Europe, and the USA) as part of both social reform movements and the growth of biological and medical knowledge (especially causation and management of infectious disease).2 Farr, Chadwick, Virchow, Koch, Pasteur, and Shattuck helped to establish the discipline on the basis of four factors: (1) decision making based on data and evidence (vital statistics, surveillance and outbreak investigations, laboratory science); (2) a focus on populations rather than individuals; (3) a goal of social justice and equity; and (4) an emphasis on prevention rather than curative care. All these elements are embedded in most definitions of public health.
The definition of public health that has perhaps best stood the test of time is that suggested by Winslow almost 90 years ago:3
“Public health is the science and art of preventing disease, prolonging life and promoting physical health and efficacy through organized community efforts for the sanitation of the environment, the control of communicable infections, the education of the individual in personal hygiene, the organization of medical and nursing services for the early diagnosis and preventive treatment of disease, and the development of social machinery which will ensure every individual in the community a standard of living adequate for the maintenance of health; so organizing these benefits in such a fashion as to enable every citizen to realize his birthright and longevity.”
The US Institute of Medicine (IOM), in its 1988 Future of public health report,4 described public health in terms of its mission, substance, and organisational framework, which, in turn, address prevention, a community approach, health as a public good, and the contributions of various partners. The IOM report defined the mission of public health as “fulfilling society's interest in assuring conditions in which people can be healthy”.4 In the Dictionary of epidemiology (2001), Last5 defined public health as “one of the efforts to protect, promote and restore the people's health. It is the combination of sciences, skills and beliefs that is directed to the maintenance and improvement of the health of all the people through collective or social actions”.
International health has a more straightforward history. For decades, it was the term used for health work abroad, with a geographic focus on developing countries and often with a content of infectious and tropical diseases, water and sanitation, malnutrition, and maternal and child health.6 Many academic departments and organisations still use this term, but include a broader range of subjects such as chronic diseases, injuries, and health systems. The Global Health Education Consortium defines international health as a subspecialty that “relates more to health practices, policies and systems…and stresses more the differences between countries than their commonalities”.7 Other research groups define international health as limited exclusively to the diseases of the developing world.8 But many find international health a perfectly usable term and have adapted it to coincide with the philosophy and content of today's globalised health practice.7, 8 International health is defined by Merson, Black, and Mills9 as “the application of the principles of public health to problems and challenges that affect low and middle-income countries and to the complex array of global and local forces that influence them”.
Global health has areas of overlap with the more established disciplines of public health and international health (table ). All three entities share the following characteristics: priority on a population-based and preventive focus; concentration on poorer, vulnerable, and underserved populations; multidisciplinary and interdisciplinary approaches; emphasis on health as a public good and the importance of systems and structures; and the participation of several stakeholders. In view of these commonalities, we are left with key questions that need to be resolved to arrive at a useful and distinctive definition for global health. We address some of these questions here.
Table.
Comparison of global, international, and public health
| Global health | International health | Public health | |
|---|---|---|---|
| Geographical reach | Focuses on issues that directly or indirectly affect health but that can transcend national boundaries | Focuses on health issues of countries other than one's own, especially those of low-income and middle-income | Focuses on issues that affect the health of the population of a particular community or country |
| Level of cooperation | Development and implementation of solutions often requires global cooperation | Development and implementation of solutions usually requires binational cooperation | Development and implementation of solutions does not usually require global cooperation |
| Individuals or populations | Embraces both prevention in populations and clinical care of individuals | Embraces both prevention in populations and clinical care of individuals | Mainly focused on prevention programmes for populations |
| Access to health | Health equity among nations and for all people is a major objective | Seeks to help people of other nations | Health equity within a nation or community is a major objective |
| Range of disciplines | Highly interdisciplinary and multidisciplinary within and beyond health sciences | Embraces a few disciplines but has not emphasised multidisciplinarity | Encourages multidisciplinary approaches, particularly within health sciences and with social sciences |
What is global? Must a health crisis cross national borders to be deemed a global health issue? We should not restrict global health to health-related issues that literally cross international borders. Rather, in this context, global refers to any health issue that concerns many countries or is affected by transnational determinants, such as climate change or urbanisation, or solutions, such as polio eradication. Epidemic infectious diseases such as dengue, influenza A (H5N1), and HIV infection are clearly global. But global health should also address tobacco control, micronutrient deficiencies, obesity, injury prevention, migrant-worker health, and migration of health workers. The global in global health refers to the scope of problems, not their location. Thus—like public health but unlike international health—global health can focus on domestic health disparities as well as cross-border issues. Global health also incorporates the training and distribution of the health-care workforce in a manner that goes beyond the capacity-building interest of public health.
Is global health mainly directed to infectious disease and maternal and child health issues or does it also address issues such as chronic diseases, injuries, mental health, and the environment? Infectious diseases and maternal and child health have dominated international health and continue to receive the most attention and interest in global health. However, global health has to embrace the full breadth of important health threats. This broad set of priorities might mean accepting that, for many countries, the epidemiological transition is a continuing process. Simultaneous effort needs to be expended on undernutrition and overnutrition, HIV/AIDS and tobacco, malaria and mental health, tuberculosis and deaths due to motor vehicle accidents. Infectious agents are communicable and so are parts of the western lifestyle (ie, dietary changes, lack of physical activity, reliance on automobile transport, smoking, stress, urbanisation). Burden of illness should be used as a criterion for global-health priority setting.
How does global health relate to globalisation? The spread of health risks and diseases across the world, often linked with trade or attempted conquest, is not new to public health or international health. Plague spread across Europe and Asia in the middle ages; quarantine was developed in 14th-century Venice; smallpox and measles were introduced to the New World by European invaders in the 16th century; the same explorers took tobacco from the Americas to Europe and beyond, leading to premature disease and death; and opium was sold to China in the 18th and 19th centuries as a product of trade and subjugation by imperial western powers. Nevertheless, the rapid increase in speed of travel and communication, as well as the economic interdependency of all nations, has led to a new level and speed of global interconnectedness or globalisation, which is a force in shaping the health of populations around the world.
Must global health operate only within a context of a goal of social/economic equity? The quest for equity is a fundamental philosophical value for public health. The promotion of social and economic equity, and reduction of health disparities has been a key theme in domestic public health, international health, and global health. Up to now, most health initiatives in countries without sufficient resources to deal with their own health problems have come about through the assistance of wealthier countries, organisations, and foundations. Although this assistance is understandable, it does not help us to distinguish global health as a specialty of study and practice.
Global health has come to encompass more complex transactions between societies. Such societies recognise that the developed world does not have a monopoly on good ideas and search across cultures for better approaches to the prevention and treatment of common diseases, healthy environments, and more efficient food production and distribution. The preference for use of the term global health where international health might previously have been used runs parallel to a shift in philosophy and attitude that emphasises the mutuality of real partnership, a pooling of experience and knowledge, and a two-way flow between developed and developing countries. Global health thus uses the resources, knowledge, and experience of diverse societies to address health challenges throughout the world.
What is the interdisciplinary scope of global health? Professionals from many diverse disciplines wish to contribute to improving global health. Although global health places greater priority on prevention, it also embraces curative, rehabilitative, and other aspects of clinical medicine and the study of basic sciences. But these latter areas are less central to the core elements of public health than are its population-based and preventive orientations. Clearly, many disciplines, such as the social and behavioural sciences, law, economics, history, engineering, biomedical and environmental sciences, and public policy can make great contributions to global health. Thus, global health encompasses prevention, treatment, and care; it is truly an interdisciplinary sphere.
A steady evolution of philosophy, attitude, and practice has led to the increased use of the term global health. Thus, on the basis of this analysis, we offer the following definition: global health is an area for study, research, and practice that places a priority on improving health and achieving equity in health for all people worldwide. Global health emphasises transnational health issues, determinants, and solutions; involves many disciplines within and beyond the health sciences and promotes interdisciplinary collaboration; and is a synthesis of population-based prevention with individual-level clinical care.
We call for the adoption of a common definition of global health. We will all be best served (and best serve the health of others around the world) if we share a common definition of the specialty in which we work and to which we encourage others to lend their efforts.
Acknowledgments
Acknowledgments
We thank George Alleyne, Lincoln Chen, William Foege, Andy Haines, Mohammed Hassar, Venkat Narayan, Sharifa Saif Al-Jabri, Barry Schoub, and Olive Shisana for their comments and suggestions.
Contributors
All authors contributed to the writing and editing of the manuscript. The Consortium of Universities for Global Health (CUGH) Executive Board developed the definition and reviewed and edited the manuscript.
CUGH Executive Board
Haile Debas (University of California, San Francisco, CA, USA); King Holmes (University of Washington, Seattle, WA, USA); Gerald Keusch (Boston University, Boston, MA, USA); Jeffrey Koplan (Emory University, Atlanta, GA, USA); Michael Merson (Duke University, Durham, NC, USA); Thomas Quinn (Johns Hopkins University, Baltimore, MD, USA); Judith N Wasserheit (University of Washington, Seattle, WA, USA).
Conflicts of interest
We declare that we have no conflicts of interest.
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