Global health

Global health is a field at the intersection of several disciplines--epidemiology, economics, demography and sociology--that is concerned with international health issues. The term global health, as opposed to International Health, implies consideration of the health needs of the people of the whole planet above the concerns of particular nations. The terminology has become more popular given the rise in importance of actors beyond governmental or intergovernmental organisations and agencies. Examples of global health issues include international law (and its effect on health systems), global warming (and the implications for population health), globalization and health, the Framework Convention on Tobacco Control (FCTC) and The Global Alliance for Vaccines and Immunization (GAVI), among many others.

History

In 1948, the member states of the newly formed United Nations gathered together 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.

One of the greatest accomplishments of the international health community since then was the eradication of smallpox. The last naturally occurring case of the infection was recorded in 1977. But in a strange way, success with smallpox bred overconfidence and subsequent efforts to eradicate malaria and other diseases have not been as effective. Indeed, there is now debate within the global health community as to whether eradication campaigns should be abandoned in favor of less costly and perhaps more effective primary health and containment programs.

For a variety of reasons, fewer resources were made available for global health in the late 1970s and 1980s—just at the moment when the AIDS virus was beginning its worldwide spread.

The beginning of the 21st century, however, saw renewed interest, particularly after Microsoft Chairman Bill Gates started spending billions of dollars on international health initiatives and research.

Viewing global health

Many perspectives exist to the study of global health. A primary perspective emphasizes the cost-effectiveness and cost benefit approaches. Cost-effectiveness analysis compares the costs and health effects of an intervention to assess whether it is worth doing from the economic perspective. It is necessary to distinguish between independent interventions and mutually exclusive interventions. For independent interventions, average cost-effectiveness ratios suffice, but for mutually exclusive interventions it is essential to use incremental cost-effectiveness ratios if the objective – to maximise healthcare effects given the resources available – is to be achieved.

Another approach, embraced by ethicists and bioethicists, emphasizes distributional considerations. For example, the Rule of Rescue is a rule coined by A.R. Jonsen in 1986 that is currently used in a variety of bioethics contexts. The rule of rescue rule specifies that it is 'a perceived duty to save endangered life where possible' (Bochner et al, 1994, pp901)

A third approach emphasizes political economy considerations applied to global health. Political economy originally was the term for studying production, buying and selling, and their relations with law, custom, and government. Originating in moral philosophy (e.g. Adam Smith was Professor of Moral Philosophy at the University of Glasgow), political economy of health is the study of how economies of states — polities, hence political economy - influence aggregate population health outcomes.

Global Health Measurement

Analysis of global health hinges on how to measure health burden internationally. Several measures exist: DALY, QALY, DFLEs and mortality measurements.

Disability Adjusted Life Years

For example, DALYs for a disease are the sum of the years of life lost due to premature mortality (YLL) in the population and the years lost due to disability (YLD) for incident cases of the health condition. The DALY is a health gap measure that extends the concept of potential years of life lost due to premature death (PYLL) to include equivalent years of 'healthy' life lost in states of less than full health, broadly termed disability. One DALY represents the loss of one year of equivalent full health.

The Disability Adjusted Life Year or DALY is a health gap measure that extends the concept of potential years of life lost due to premature death (PYLL) to include equivalent years of ‘healthy’ life lost by virtue of being in states of poor health or disability (1). The DALY combines in one measure 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 and the burden of disease as a measurement of the gap between current health status and an ideal situation where everyone lives into old age free of disease and disability.

Quality Adjusted Life Years

A QALY (quality-adjusted life years) is a numerical description of the value that a medical procedure or service can be expected to provide to groups of patients with similar medical conditions. QALYs attempt to combine expected survival with expected quality of life into a single number: if an additional year of healthy life expectancy is worth a value of one (year), then a year of less healthy life expectancy 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 simulate 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.

Health conditions

Childhood mortality

According to UNICEF, 10.5 million children die before they reach 5 years of age. That translates to roughly 30,000 children dying every day.

Global health and HIV/AIDS

Main articles: HIV and AIDS

Human Immunodeficiency Virus is a retrovirus that first appeared in humans in the early 1980s. The term “HIV-positive” is used to describe someone infected with this disease. HIV progresses to a point where the infected person has AIDS or Acquired Immunodeficiency Syndrome. HIV becomes AIDS because the virus had depleted CD4+ T-cells that are necessary for a healthy immune system. Today, there are treatments that can prolong life and delay the onset of AIDS by minimizing the amount of HIV in the body.

HIV/AIDS is transmitted through bodily fluids. Unprotected sex, intravenous drug use, blood transfusions, and unclean needles spread HIV through blood and other fluids. Once thought to be a disease that only affected drug users and homosexuals, it can affect anyone. It can also be passed from a pregnant woman to her unborn child during pregnancy, or after pregnancy through breast milk. While it is a global disease that can affect anyone, there are disproportionately high infection rates in certain regions of the world. Additionally, the primary method of spreading HIV is through heterosexual intercourse. Because of the biological presence of more surface area in the receptive sex organs of females, women represent a higher rate of infection for the disease.

HIV/AIDS has been linked to cultures since its discovery. The disease was originally referred to as GRID for Gay-Related Immune Deficiency and initially thought to be related solely to the gay community. Because of this view and the lack of information about the disease, blood banks were not adequately screened leading to the origin of a much larger infected population. Finally, although women are more susceptible to the disease, there are many cultures in which women have no access to contraceptive or barrier devices, often leading to infection. This serves to only spread the HIV further.

This diagram depicts the route of transmission of HIV/AIDS, based on the development of the epidemic in Russia. It represents a common relationship between drug users, sex workers, and peripheral persons (other sexual partners).

( http://www.avert.org/media/images/russia_aids_web.gif)

Region: HIV/AIDS is a global problem and infects people all over the world, but certain regions have much higher infection rates. HIV/AIDS is most prevalent in Sub-Saharan Africa, where it is considered pandemic. It is also prevalent in South and Southeast Asia, Latin America, Eastern Europe, Russia, and urban areas in more developed nations.

Region HIV Infection (millions of people) Sub-Saharan Africa 25.8 Asia 8.3 Eastern Europe and Central Asia 1.6 Caribbean .3 Latin America 1.8 North America, Western and Central Europe 1.9 Middle East and North Africa .51 Oceania .074

• [1]

Examples

South Africa

Age group (years) 2000 prevalence % 2001 prevalence % 2002 prevalence % 2003 prevalence % 2004 prevalence % 2005 prevalence % <20 16.1 15.4 14.8 15.8 16.1 15.9 20-24 29.1 28.4 29.1 30.3 30.8 30.6 25-29 30.6 31.4 34.5 35.4 38.5 39.5 30-34 23.3 25.6 29.5 30.9 34.4 36.4 35-39 15.8 19.3 19.8 23.4 24.5 28.0 40+ 11.0 9.8 17.2 15.8 17.5 19.8 (http://www.avert.org/safricastats.htm)

South Africa 2003 Adults with HIV/AIDS (15-49) 5,300,000 Women with HIV/AIDS (age 15-49) 3,100,000 AIDS Deaths 320,000 Adult HIV Prevalence % 18.8 Children with HIV/AIDS (age 0-14) 240,000 Orphans due to AIDS 1,200,000 (http://www.unaids.org/en/Regions_Countries/Countries/south_africa.asp)

Vietnam 2003 Adults with HIV/AIDS (15-49) 250,000 Women with HIV/AIDS (age 15-49) 84,000 AIDS Deaths 13,000 Adult HIV Prevalence % .5 (http://www.unaids.org/en/Regions_Countries/Countries/viet_nam.asp)

Argentina 2003 Adults with HIV/AIDS (age 15-49) 130,000 Women with HIV/AIDS (age 15-49) 36,000 AIDS Deaths 4,300 Adult HIV Prevalence % .6 (http://www.unaids.org/en/Regions_Countries/Countries/argentina.asp)

Prevalence of HIV/AIDS in sub-Saharan Africa: The prevalence of HIV/AIDS in sub-Saharan Africa is due to several different factors. Many scientists believe that HIV originated in Africa. There are two different strains of HIV, HIV-1 and HIV-2, one of which is almost exclusively found in Africa. Additionally, poverty and HIV prevalence have been shown to correspond as poverty prevents adequate education about the disease as well the purchase of the expensive drugs necessary for its treatment. A disproportionately large percentage of sub-Saharan Africans live in extreme poverty leading to the continued cycle of HIV infection.

Success Story: Thailand Thailand is one of few nations to have reduced the spread of HIV/AIDS. Through mass media campaigns, increased condom use, and halving the population of sex workers, Thailand reduced the number of new infections to 21,000 in 2003 after a rate of 140,000 in 1991. Also, AIDS education programs were implemented into every school, “anti-AIDS” commercials were broadcast ever hour on radio and television stations, and condoms were distributed at commercial sex houses. The “100% Condom Program” (that distributed these condoms) was most effective, requiring use on both the worker and customer, closing establishments that did not follow this rule. There have since been two more phases in Thailand’s fight against HIV/AIDS, ‘The National Plan for Prevention and Alleviation of the AIDS Problem” from 1997 to 2001 and 2002 to 2006. (http://www.avert.org/aidsthai.htm) Despite these success stories, however, there is still much ground to cover in the treatment and prevention of HIV/AIDS.

• http://www.unaids.org/en/Coordination/MakingProgress/default.asp

Obstacles to recovery

Global Disparity

Ninety-six percent of people with HIV live in the developing world, most in sub-Saharan Africa. The epidemic continues to grow in this region, with nearly a million new infections between 2003 and 2005.

In six African countries, (Botswana, Lesotho, Namibia, South Africa, Swaziland and Zimbabwe), more than one in five of all pregnant women have HIV/AIDS. In Swaziland, nearly 40% of pregnant women are HIV-positive.

Without prevention efforts, 35% of children born to an HIV positive mother will become infected with HIV. At least a quarter of newborns infected with HIV die before age one, and up to 60% will die before reaching their second birthday.

(From http://globalhealth.org/view_top.php3?id=227)

Ignorance of the Infected

A recent CDC report found that of a population sampled that were found to be HIV positive, 48% did not know that were infected with HIV.

Ignorance of the Disease

“People are more ignorant of how HIV is transmitted than they were five years ago, a poll says. Despite rising infection levels in the UK, 12% fewer people know the virus can be passed on through unprotected sex, the survey of 2,048 people revealed.”

(From http://news.bbc.co.uk/1/hi/health/4885120.stm) One of the aspects of HIV/AIDS that makes it particularly difficult to address is the fact that it straddles the line between social and infectious disease. It is a highly infectious disease given certain behaviors. Questions immediately facing global health advocates include, “should attempts be made to curtain HIV/AIDS behavioral origins, develop treatment for those infected, or advocate preventive measures for those engaging in high-risk behavior?”

Negative behavioral connotations

HIV/AIDS was originally termed GRID for Gay-Related Immune Deficiency due to its initial emergence among gay communities. Today most of the newly infected individuals are women that become infected through heterosexual intercourse.

Nutrition

Among children under the age of five in the developing world, malnutrition contributes to 53% of deaths associated with infectious diseases. Greater than two billion people in the world suffer from micronutrient deficiencies (including lack of iron, zinc, vitamin A, iodine). Malnutrition impairs the immune system, thereby increasing the frequency, severity, and duration of childhood illnesses (including measles, pneumonia and diarrhoea) while making children more susceptible to infectious diseases.

An individual’s nutrition not only affects their health, but their ability to survive, their cognitive development and their work capacity. Appropriate and affordable interventions are necessary to improve nutrition throughout the world. These ought to be paired with other health promoting interventions such as clean water and sanitation.

Goal #1 in the United Nation’s (UN) Millennium Development Goals is to eradicate extreme poverty and hunger. Between the years of 1990 and 2015 it hopes to halve the proportion of people who suffer from hunger. This will be done through mobilizing domestic resources, scaling up public investment, international aid, and various other regional efforts. Sub-Sahara Africa and Southern Asia are the regions worst affected by chronic hunger. As of 2006, the levels of chronic hunger in these regions (in which people lack the food needed to meet their daily needs), has made progress, though not at the desired rate. Globally, the number of people going hungry increased in the years from 1995-1997 to 2001-2003.

Diarrhoeal Diseases

Diarrhoea may be caused through infection by bacterial, viral or parasitic organisms. Poor sanitation can lead to its prevalence through water, food, utensils, hands and flies. Diarrhoea may result in dehydration, which is even more severe in an already malnourished child. Though intravenous treatments (IV) are effective for maintaining hydration and replacing electrolytes during severe diarrhoeal episodes in developed countries, such resources are often not available in many developing countries, leading to high diarrhoea-related mortality rates. Diarrhoeal diseases are responsible for 17 per cent of deaths among children under the age of five worldwide, making them the second most common cause of child deaths globally. In 1990, diarrhoeal disease was the 2nd highest contributor to the disease burden in the world and it’s anticipated that it will be the 9th highest contributor by 2020. In developing regions diarrhoeal diseases are the 4th leading cause of death overall.

A method of oral rehydration therapy has been developed to treat diarrhoea in areas lacking resources. By mixing water, sugar and salt and administering it to the affected child, dehydration can be prevented. In specified locations this technique was taught to one woman of each household, cutting child mortality in half.

Micronutrient deficiency

More than 2 billion people are at risk of iron, vitamin A, iodine, and zinc deficiencies. The lack of such micronutrients affects the general functioning of the body, often resulting in a person being underweight, having their daily functions impaired, and increasing the severity of common infections (e.g. measles, diarrhea). Micronutrient deficiencies also compromise intellectual potential, growth, development and adult productivity.

Interventions include micronutrient supplementation/fortification. In the 1950s a major public health initiative in developing countries included the fortification of basic grocery store foods. Other interventions include the delivery of concentrated micronutrient drops or capsules. Education in proper nutrition and information detailing the nutrient capacity of local foods will further alleviate this problem.

Fifty million children under the age of five are affected by vitamin A deficiency. Such deficiency has been linked with night blindness. Alfred Somer discovered that rod cells in the eye can’t make a protein called nodopsin without vitamin A. Nodopsin allows people to see in low light conditions. Without it people are unable to see at night and their cornea eventually erodes, leading to total blindness. Additionally, vitamin A gives necessary strength to the epithelial lining of organs. Without this individuals are more susceptible to disease.

While in many places a vitamin A injection is not practical, clinically vitamin A drops have allowed patients to see perfectly the next day. Long term study showed that vitamin A also has the potential to reduce child mortality rates by 23-34% in areas where vitamin A deficiency is common.

In Nepal, vitamin A is distributed in capsules. Public health workers trained local women to become volunteers. Rallies and parades were hosted to encourage people to receive the medication. Now this serves as a model program for 70 other countries. It is estimated that thus far this cost effective program has saved some 250,000 children.

Iron Deficiency affects approximately one-third of the worlds' women and children. It causes anemia and is associated with 20% of maternal mortality, 22% of prenatal mortality and 18% of mental retardation globally. In children, iron deficiency compromises mental development and learning capacity.

Zinc Deficiency increases the risk of mortality from diarrhea, pneumonia and malaria. Supplements have been proven to reduce the duration of diarrhea episodes.

Iodine deficiency is the leading cause of preventable mental retardation. As many as 50 million infants born annually are at risk of iodine deficiency. Global efforts for universal salt iodization are helping eliminate this problem.

Dietary diversification is an intervention which (in addition to supplementation, fortification, and other methods described above) strives to increase the consumption of Vitamin A, iron and other micronutrients. By improving access to micronutrient rich and locally produced food, this type of intervention is potentially cost efficient and sustainable. Education and promotion of a diverse diet are crucial to the success of such interventions. Such programs are currently in use in countries including Indonesia, Bangladesh, Mali and the Philippines.

Obesity

For the first time in history, there are more overweight people in the world than underweight people. This reflects industrialization, urbanization, economic development and increasing food market globalization. Such advancements have essentially engineered physical activity out of life in many developed countries. In such locations, there is also an abundance of food available to foster obesity. Obesity is preventable and very expensive to treat. It is associated with numerous chronic diseases including cardiovascular conditions, diabetes, stroke, cancers and respiratory diseases. About 46% of the global burden of disease is accounted for by obesity.

Obesity does not only affect developed countries. The rates of type 2 diabetes, associated with obesity, have been on the rise in countries traditionally noted for hunger levels. In India for instance there are about 35 million people who currently have type 2 diabetes. It’s estimated that in 20 years 75 million of India’s 1.1 billion residents will have type 2 diabetes.

External links

• Disease Control Priorities Project (DCPP)
• Global Health Council
• Global Health Reporting (Kaiser Family Foundation)
• Medical School for International Health
• Global Health Update (Time.com)
• London School of Hygiene and Tropical Medicine
• Novartis Institute of Tropical Medicine (Singapore)
• Science and Development Network
• World Health News (Harvard)
• World Health Organization
• Center for Global Health at the University of Virginia
• Action for Global Health