Global Health

Global health is the health of populations in a worldwide context;[1] it has been defined as "the area of study, research, and practice that places a priority on improving health and achieving equity in health for all people worldwide".[2] Problems that transcend national borders or have a global political and economic impact are often emphasized.[3] Thus, global health is about worldwide health improvement (including mental health), reduction of disparities, and protection against global threats that disregard national borders,[4][5] including the most common causes of human death and years of life lost from a global perspective.

Global health is not to be confused with international health, which is defined as the branch of public health focusing on developing nations and foreign aid efforts by industrialized countries.[6]

One way that global health can be measured is through the prevalence of various global diseases in the world and their threat to decrease life expectancy in the present day. Estimates suggest that in a pre-modern, poor world, life expectancy was around 30 years in all regions of the world (mainly due to high infant mortality).[7] Another holistic perspective called One Health can be used to address global health challenges and to improve global health security.[8][9][10]

The predominant agency associated with global health (and international health) is the World Health Organization (WHO). Other important agencies impacting global health include UNICEF and World Food Programme (WFP). The United Nations system has also played a part in cross-sectoral actions to address global health and its underlying socioeconomic determinants with the declaration of the Millennium Development Goals[11] and the more recent Sustainable Development Goals.

Definition

Open Global Health at OpenCon 2015

Global health employs several perspectives that focus on the determinants and distribution of health in international contexts.

Medicine describes the pathology of diseases and promotes prevention, diagnosis, and treatment.[12]

Public health emphasizes the health of populations.[13]

Epidemiology helps identify risk factors and causes of health problems.[14]

Demography provides data for policy decisions.[15]

Economics emphasizes the cost-effectiveness and cost-benefit approaches for the optimal allocation of health resources.[16]

Other social sciences such as sociology, development studies, psychology, anthropology, cultural studies, and law can help understand the determinants of health in societies.

Both individuals and organizations working in the domain of global health often face many questions regarding ethical and human rights. Critical examination of the various causes and justifications of health inequities is necessary for the success of proposed solutions. Such issues are discussed at the bi-annual Global Summits of National Ethics/Bioethics Councils.[17]

History

See also: Timeline of global health

Life expectancy by world region, from 1770 to 2018

Important steps were taken towards global co-operation in health with the formation of the United Nations (UN) and the World Bank Group in 1945, after World War II. In 1948, the member states of the newly formed United Nations gathered to create the World Health Organization. A cholera epidemic that took 20,000 lives in Egypt in 1947 and 1948 helped spur the international community to action.[18] The WHO published its Model List of Essential Medicines, and the 1978 Alma Ata declaration underlined the importance of primary health care.[19]

At a United Nations Summit in 2000, member nations declared eight Millennium Development Goals (MDGs),[20] which reflected the major challenges facing human development globally, to be achieved by 2015.[21] The declaration was matched by unprecedented global investment by donor and recipient countries. According to the UN, these MDGs provided an important framework for development and significant progress has been made in a number of areas.[22] However, progress has been uneven and some of the MDGs were not fully realized including maternal, newborn and child health and reproductive health.[22] Building on the MDGs, a new Sustainable Development Agenda with 17 Sustainable Development Goals (SDGs) has been established for the years 2016–2030.[22] The first goal being an ambitious and historic pledge to end poverty.[23] On 25 September 2015, the 193 countries of the UN General Assembly adopted the 2030 Development Agenda titled Transforming our world: the 2030 Agenda for Sustainable Development.[23]

Several major initiatives began in the 2000s, including the vaccine alliance GAVI in 2000, The Global Fund to Fight AIDS, Tuberculosis and Malaria in 2002, U.S. President's Emergency Plan for AIDS Relief in 2003, and the U.S. President's Malaria Initiative in 2005. In this decade and as part of the Monterrey Consensus (which did not pursue goals as aggressively as many activists had urged),[24] an increasing emphasis was put on measuring improvement in health outcomes, rather than merely the amount of money spent.[25]

In 2015 a book titled To Save Humanity was published, with nearly 100 essays regarding today's most pressing global health issues.[26] The essays were authored by global figures in politics, science, and advocacy ranging from Bill Clinton to Peter Piot, and addressed a wide range of issues including vaccinations, antimicrobial resistance, health coverage, tobacco use, research methodology, climate change, equity, access to medicine, and media coverage of health research.

Global health as a discipline is frequently regarded to be of imperial origin, and there have been calls for its decolonisation.[27][28][29] The global health ecosystem has also been criticised as having a feudal structure, acting for a small group of institutions and individuals based in high-income countries which acts similar to an imperial "Crown".[30]

Measures

Measures of global health include disability-adjusted life year (DALY), quality-adjusted life years (QALYs), and mortality rate.[31]

Disability-adjusted life years

Disability-adjusted life years per 100,000 people in 2004:

Main article: Disability-adjusted life year

The DALY is a summary measure that combines the impact of illness, disability, and mortality by measuring the time lived with disability and the time lost due to premature mortality. One DALY can be thought of as one lost year of "healthy" life. The DALY for a disease is the sum of the years of life lost due to premature mortality and the years lost due to disability for incident cases of the health condition.

Quality-adjusted life years

Main article: Quality-adjusted life year

QALYs combine expected survival with expected quality of life into a single number: if an additional year of healthy life is worth a value of one (year), then a year of less healthy life is worth less than one (year). QALY calculations are based on measurements of the value that individuals place on expected years of survival. Measurements can be made in several ways: by techniques that replicate gambles about preferences for alternative states of health, with surveys or analyses that infer willingness to pay for alternative states of health, or through instruments that are based on trading off some or all likely survival time that a medical intervention might provide in order to gain less survival time of higher quality.[31]

Infant and child mortality

Main articles: Infant mortality and Child mortality

Infant mortality and child mortality for children under age 5 are more specific than DALYs or QALYs in representing the health in the poorest sections of a population, and are thus especially useful when focusing on health equity.[32] added section

Morbidity

Main article: Morbidity

Morbidity measures include incidence rate, prevalence, and cumulative incidence, with incidence rate referring to the risk of developing a new health condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during a time period, morbidity is better expressed as a proportion or a rate.

Health topics

Infectious diseases

Respiratory tract infections

Main article: Respiratory tract infection

Infections of the respiratory tract and middle ear are major causes of morbidity and mortality worldwide.[33] Some respiratory infections of global significance include tuberculosis, measles, influenza, coronaviruses and pneumonias caused by Mycobacterium tuberculosis, Morbillivirus, Haemophilus influenzae and Pneumococci respectively. The spread of respiratory infections is exacerbated by crowded conditions, and poverty is associated with more than a 20-fold increase in the relative burden of lung infections.[34]

Diarrheal illnesses

Main article: Diarrhea

Diarrhea is the second most common cause of child mortality worldwide, responsible for 17% of deaths of children under age 5.[35] Poor sanitation can increase transmission of bacteria and viruses through water, food, utensils, hands, and flies. Dehydration due to diarrhea can be effectively treated through oral rehydration therapy with dramatic reductions in mortality.[36][37] Important nutritional measures include the promotion of breastfeeding and zinc supplementation. While hygienic measures alone may be insufficient for the prevention of rotavirus diarrhea,[38] it can be prevented by a safe and potentially cost-effective vaccine.[39]

HIV/AIDS

Main articles: HIV and AIDS

The HIV/AIDS epidemic has highlighted the global nature of human health and welfare and globalization has given rise to a trend toward finding common solutions to global health challenges. Numerous international funds have been set up in recent times to address global health challenges such as HIV.[40] Since the beginning of the epidemic, more than 70 million people have been infected with the HIV virus and about 35 million people have died of HIV. Globally, 36.9 million [31.1–43.9 million] people were living with HIV at the end of 2017. An estimated 0.8% [0.6–0.9%] of adults aged 15–49 years worldwide are living with HIV, although the burden of the epidemic continues to vary considerably between countries and regions. The WHO African region remains most severely affected, with nearly 1 in every 25 adults (4.1%) living with HIV and accounting for nearly two-thirds of the people living with HIV worldwide.[41] Human immunodeficiency virus (HIV) is transmitted through unprotected sex, unclean needles, blood transfusions, and from mother to child during birth or lactation. Globally, HIV is primarily spread through sexual intercourse. The risk-per-exposure with vaginal sex in low-income countries from female to male is 0.38% and male to female is 0.3%.[42] The infection damages the immune system, leading to acquired immunodeficiency syndrome (AIDS) and eventually, death. Antiretroviral drugs prolong life and delay the onset of AIDS by minimizing the amount of HIV in the body.

Malaria

Main article: Malaria

Malaria is a mosquito-borne infectious disease caused by the parasites of the genus Plasmodium. Symptoms may include fever, headaches, chills, muscle aches and nausea. Each year, there are approximately 500 million cases of malaria worldwide, most commonly among children and pregnant women in developing countries.[43] The WHO African Region carries a disproportionately high share of the global malaria burden. In 2016, the region was home to 90% of malaria cases and 91% of malaria deaths.[44] The use of insecticide-treated bed nets is a cost-effective way to reduce deaths from malaria, as is prompt artemisinin-based combination therapy, supported by intermittent preventive therapy in pregnancy. International travelers to endemic zones are advised chemoprophylaxis with antimalarial drugs like Atovaquone-proguanil, doxycycline, or mefloquine.[45] Global consumption and international trade in deforestation-associated commodities could also indirectly influence malaria risk. Many primary commodities cause deforestation and deforestation can increase malaria transmission. Consumption of such commodities in developed nations could increase malaria risk in developing nations.[46]

Bacterial pathogens

Global number of deaths (A) and YLLs (B), by pathogen and GBD super-region, 2019[47]

Overall age-standardised mortality rate per 100 000 population for 33 pathogens investigated, 2019[47]

A GBD study reported global estimates of death rates from (33) bacterial pathogens, finding such infections are contributing to one in 8 deaths (or ~7.7 million deaths), which could make it the second largest cause of death globally in 2019.[47]

Neglected tropical diseases

Main article: Neglected tropical diseases

More than one billion people were treated for at least one neglected tropical disease in 2015.[48] For instance, neglected tropical diseases are a diverse group of infectious diseases that are endemic in tropical and subtropical regions of 149 countries, primarily effecting low and middle income populations in Africa, Asia, and Latin America. They are variously caused by bacteria (trachoma, leprosy), viruses (dengue,[49] rabies), protozoa (human African trypanosomiasis, chagas), and helminths (schistosomiasis, onchocerciasis, Soil transmitted helminths).[50] The Global Burden of Disease Study concluded that neglected tropical diseases comprehensively contributed to approximately 26.06 million disability-adjusted life years in 2010, as well as significant deleterious economic effects.[51] In 2011, the World Health Organization launched a 2020 Roadmap for neglected tropical diseases, aiming for the control or elimination of 10 common diseases.[52] The 2012 London Declaration builds on this initiative, and called on endemic countries and the international community to improve access to clean water and basic sanitation, improved living conditions, vector control, and health education, to reach the 2020 goals.[53] In 2017, a WHO report cited "unprecedented progress" against neglected tropical diseases since 2007, especially due to mass drug administration of drugs donated by pharmaceutical companies.[54]

Pandemic prevention and preparedness

Pandemics have an impact on global health.

This section is an excerpt from Pandemic prevention.[edit]

Pandemic prevention is the organization and management of preventive measures against pandemics. Those include measures to reduce causes of new infectious diseases and measures to prevent outbreaks and epidemics from becoming pandemics. It is not to be mistaken for pandemic preparedness or mitigation (e.g. against COVID-19) which largely seek to mitigate the magnitude of negative effects of pandemics, although the topics may overlap with pandemic prevention in some respects.

Pandemics typically arise naturally from interactions between humans and animals,[55] but emerging technologies are also expected to facilitate the synthesis and enhancement of dangerous pathogens, making bioterrorism and laboratory accidents emerging threats.[56][57]

Pandemic prevention measures include early detection systems, international coordination with information sharing, laboratory biosafety protocols, oversight of gain-of-function research, restricting access to dual-use biotechnology, monitoring spillover risks in wild animal populations, regulating wildlife trade and wet markets, reducing intensive animal farming, protecting ecosystems, and strengthening public health care systems.

In May 2025, all Member States of the World Health Organization (WHO) formally adopted by the world's first Pandemic Agreement.[58]

This section is an excerpt from Pandemic § Concerns about future pandemics.[edit]

Prevention of future pandemics requires steps to identify future causes of pandemics and to take preventive measures before the disease moves uncontrollably into the human population.

For example, influenza is a rapidly evolving disease which has caused pandemics in the past and has the potential to cause future pandemics. WHO collates the findings of 144 national influenza centres worldwide which monitor emerging flu viruses. Virus variants which are assessed as likely to represent a significant risk are identified and can then be incorporated into the next seasonal influenza vaccine program.[59]

In a press conference on 28 December 2020, Mike Ryan, head of the WHO Emergencies Program, and other officials said the current COVID-19 pandemic was "not necessarily the big one" and "the next pandemic may be more severe." They called for preparation.[60] WHO and the UN have warned the world must tackle the cause of pandemics and not just the health and economic symptoms.[61]

Health research and development

See also: Funding of science and Research question § Aggregated research questions and coordination

[icon]

This section needs expansion. You can help by adding to it. (December 2022)

The global health approach could foster international collaboration in medical research and development and share of its results such as vaccines, optimizing overall global health for citizens. The U.S. Agency for International Development's new Global Health Research and Development Strategy 2023–2028 includes plans to coordinate with such stakeholders in support of innovative global health product development and work with other agencies like the CDC and National Institutes of Health. Another approach to health would be the innovation of vaccines. The Washington Post reported the US government's new five billion dollar budget on vaccines to prevent Covid variants because the Vaccines' access and public-private partnerships are important.[62] Often the relevance of mechanisms to stimulate research and development is limited by national scopes and "by the transnational nature of the problem which asks for an international approach".[63] Financing models, creation of evidence-based recommendations, and logistics may be part of that.[64]

A seminal article by Thomas Pogge, published in Metaphilosophy in 2005, addresses the global health crisis, in which one-third of all human deaths are due to poverty-related causes, the majority of which are preventable. Pogge critiques the existing patent regime, particularly the TRIPS agreement, for its role in limiting access to essential medicines and violating human rights. Pogge proposes a reform of the global health system with the objective of making medical knowledge freely available as a global public good. The reform includes providing the results of successful drug development as public goods, rewarding inventor firms based on the impact of their inventions on the global disease burden, and ensuring a fair and feasible allocation of costs. The article argues that this reform would align the interests of pharmaceutical companies with those of patients and generic drug producers, incentivize research into neglected diseases, and be cost-effective. It also discusses the moral urgency of addressing the global health crisis and the responsibility of high-income countries to support reforms that benefit the global poor. It concludes by emphasizing the feasibility and political realism of the proposed reform, which aims to extend the benefits of medical advancements to the poor and realize human rights more fully.[65]

Maternal health

Main articles: Maternal health and Reproductive health

Complications of pregnancy and childbirth are the leading causes of death among women of reproductive age. In many developing countries, a woman dies from complications from childbirth approximately every minute.[66] According to the World Health Organization's 2005 World Health Report, poor maternal conditions are the fourth leading cause of death for women worldwide, after HIV/AIDS, malaria, and tuberculosis.[67] Most maternal deaths and injuries can be prevented, and such deaths have been largely eradicated in the developed world.[68] Targets for improving maternal health include increasing and assisting the number of deliveries accompanied by skilled birth attendants.[69] 68 low-income countries tracked by the WHO- and UNICEF-led collaboration Countdown to 2015 are estimated to hold for 97% of worldwide maternal and child deaths.[70]

Nutrition

Main articles: Human nutrition and Healthy diet

In 2010, about 104 million children were underweight, and undernutrition contributes to about one third of child deaths around the world.[71] (Undernutrition is not to be confused with malnutrition, which refers to poor proportion of food intake and can thus refer to obesity.)[72] Undernutrition impairs the immune system, increasing the frequency, severity, and duration of infections (including measles, pneumonia, and diarrhea). Infection can further contribute to malnutrition.[73]

Deficiencies of micronutrients, such as vitamin A, iron, iodine, and zinc, are common worldwide and can compromise intellectual potential, growth, development, and adult productivity.[74][75][76][77][78][79][80] Interventions to prevent malnutrition include micronutrient supplementation, fortification of basic grocery foods, dietary diversification, hygienic measures to reduce spread of infections, and the promotion of breastfeeding.

Non-communicable diseases

Main article: Non-communicable disease

Approximately 80% of deaths linked to non-communicable diseases occur in developing countries.[81] For instance, urbanization and aging have led to increasing poor health conditions related to non-communicable diseases in India. Similarly, China's rapid urbanization and modernization have been associated with increased sedentary lifestyles, contributing to the rise in NCDs in the region.[82] The fastest-growing causes of disease burden over the last 26 years were diabetes (rate increased by 80%) and ischemic heart disease (up 34%). More than 60% of deaths, about 6.1 million, in 2016 were due to NCDs, up from about 38% in 1990.[83] Increases in refugee urbanization, has led to a growing number of people diagnosed with chronic non-communicable diseases.[84]

In September 2011, the United Nations is hosting its first General Assembly Special Summit on the issue of non-communicable diseases.[85] Noting that non-communicable diseases are the cause of some 35 million deaths each year, the international community is being increasingly called to take measures for the prevention and control of chronic diseases and mitigate their impacts on the world population, especially on women, who are usually the primary caregivers.

For example, the rate of type 2 diabetes, associated with obesity, has been on the rise in countries previously troubled by hunger. In low-income countries, the number of individuals with diabetes is expected to increase from 84 million to 228 million by 2030.[86] Obesity, a preventable condition, is associated with numerous chronic diseases, including cardiovascular conditions, stroke, certain cancers, and respiratory disease. About 16% of the global burden of disease, measured as DALYs, has been accounted for by obesity.[86]

Considering that 360 million people across the world live with disabling hearing loss, including 32 million children and nearly 180 million older adults, and that chronic ear diseases, such as chronic suppurative otitis media, can lead to hearing loss and may cause life-threatening complications, the seventieth World Health Assembly on May 31, 2017 signed the resolution WHA70.13 (Agenda item 15.8) urging member states to integrate strategies for ear and hearing care within the framework of their primary health care systems, under the umbrella of universal health coverage.[87] A World Report on Hearing (WRH) was published in response to the resolution (WHA70.13), to provide guidance for Member States to integrate ear and hearing care into their national health plans.[88]

Lifestyle diseases

This section is an excerpt from Lifestyle disease.[edit]

Tobacco smoking can lead to lung cancer, considered a lifestyle disease.

Lifestyle diseases can be defined as the diseases linked to the manner in which a person lives their life. These diseases are non-communicable, and can be caused by lack of physical activity, unhealthy eating, alcohol, substance use disorders and smoking tobacco, which can lead to heart disease, stroke, obesity, type II diabetes and lung cancer.[89][90] The diseases that appear to increase in frequency as countries become more industrialized and people live longer include Alzheimer's disease, arthritis, atherosclerosis, asthma, cancer, chronic liver disease or cirrhosis, chronic obstructive pulmonary disease, colitis, irritable bowel syndrome, type 2 diabetes, heart disease, hypertension, metabolic syndrome, chronic kidney failure, osteoporosis, PCOD, stroke, depression, obesity and vascular dementia.

Concerns were raised in 2011 that lifestyle diseases could soon have an impact on the workforce and the cost of health care. Treating these non-communicable diseases can be expensive.[91] It can be critical for the patient's health to receive primary prevention and identify early symptoms of these non-communicable diseases. These lifestyle diseases are expected to increase throughout the years if people do not improve their lifestyle choices.[92]

Some commenters maintain a distinction between diseases of longevity and diseases of civilization or diseases of affluence.[93] Certain diseases, such as diabetes, dental caries and asthma, appear at greater rates in young populations living in the "western" way; their increased incidence is not related to age, so the terms cannot accurately be used interchangeably for all diseases.[94]

Commercial determinants of health refers to private sector activities that affect people's health positively or negatively such as advertisements for unhealthy food.[95]

Health-related largest causes of death

This section is an excerpt from List of causes of death by rate.[edit]

This article needs to be updated. Please help update this article to reflect recent events or newly available information. (September 2017)

Leading cause of death (2016) (world)

The following is a list of the causes of human deaths worldwide for different years arranged by their associated mortality rates. Some causes listed include deaths also included in more specific subordinate causes, and some causes are omitted, so the percentages may only sum approximately to 100%. The causes listed are relatively immediate medical causes, but the ultimate cause of death might be described differently. For example, tobacco smoking often causes lung disease or cancer, and alcohol use disorder can cause liver failure or a motor vehicle accident. For statistics on preventable ultimate causes, see preventable causes of death.

In 2002, there were about 57 million deaths. In 2005, according to the World Health Organization (WHO) using the International Classification of Diseases (ICD), about 58 million people died.[96] In 2010, according to the Institute for Health Metrics and Evaluation, 52.8 million people died.[97] In 2016, the WHO recorded 56.7 million deaths[98] with the leading cause of death as cardiovascular disease causing more than 17 million deaths (about 31% of the total) as shown in the chart to the side. In 2021, there were approx. 68 million deaths worldwide, as per WHO report.[99]

Besides frequency, other measures to compare, consider, and monitor trends of causes of deaths include disability-adjusted life year (DALY) and years of potential life lost (YPLL).

This section is an excerpt from List of causes of death by rate § Developed vs. developing economies.[edit]

Global number of deaths (A) and YLLs (B), by bacterial pathogen (of 33) and GBD super-region, 2019[100]

Top causes of death, according to the World Health Organization report for the calendar year 2001:[101]