Global health

Global health is a field at the intersection of several social science disciplines--demography, economics, epidemiology, political economy and sociology. It focuses on determinants and distribution of health in international contexts. The term global health comprises consideration of population health in a global context and above the concerns or perspectives of particular nations, including the rise in importance of actors beyond governmental or intergovernmental organisations and agencies. [The World Health Organization and the Transition From "International" to "Global" Public Health. Brown et al, AJPH: Jan 2006, Vol 96, No 1. http://www.ajph.org/cgi/reprint/96/1/62]

A definition that captures modern global health is that of Families USA's Global Health Initiative: "Global health refers to health problems that transcend national borders—problems such as infectious and insect-borne diseases that can spread from one country to another. It also includes health problems that are of such magnitude that they have a global political and economic impact." [cite book | last = Initiative | first = Global Health | authorlink = Global Health Initiative| title = Why Global Health Matte | publisher = FamiliesUSA | date = 2008 | location = Washington, DC| url = http://www.familiesusa.org/issues/global-health/matters/}]

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. [History of WHO, http://www.who.int/library/historical/access/who/index.en.shtml]

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. [Official Gates bio, http://www.microsoft.com/billgates/bio.asp]

Disciplinary Perspectives On Global Health

Epidemiology, economics, demography, ethicists and political economists study global health issues.

A primary perspective emphasizes the cost-effectiveness and cost benefit approaches for both individual and population health allocation. Aggregate analysis from the perspective of governments, NGOs and Foundations for global health allocation focuses on the use of cost-effectiveness and cost-benefit analysis for the health sector. Cost-effectiveness analysis compares the costs and health effects of an intervention to assess whether health investments are worthwhile from 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. Individual health analysis from this perspective focuses on the demand and supply of health. The demand for health care is a derived demand from the demand for health, more generally. Health care is demanded as a means for consumers to achieve a larger stock of "health capital." The demand for health is unique, because individuals allocate resources in order to both consume and produce health.The optimal level of investment in health occurs where the marginal cost of health capital is equal to the marginal benefit resulting from it (MC=MB). With the passing of time, health depreciates at some rate δ. The general interest rate in the economy is denoted by r. Supply of health focuses on provider incentives, market creation, market organization, issues related to information assymetries, the role of NGOs and governments in health provision.

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) Recent bioethics research [International Health Inequalities and Global Justice: A Concluding Challenge. Daniels, Norman. http://iis-db.stanford.edu/evnts/4925/international_inequalities.pdf] examines what kinds of international obligations of justice exist broadly clustered in three areas: (1) When Are International Inequalities in Health Unjust?; (2) Where Do International Health Inequalities Come From?; (3) How do we meet health needs justly if we can't meet them all?

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.

Life Expectancy

Life expectancy is a statistical measure of the average life span (average length of survival) of a specified population. It most often refers to the expected age to be reached before death for a given human population (by nation, by current age, or by other demographic variables). Life expectancy may also refer to the expected time remaining to live, and that too can be calculated for any age or for any group.

Disability Adjusted Life Years

The disability-adjusted life-year (DALY) is a summary measure that combines the impact of illness, disability and mortality on population health. 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. 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. One DALY represents the loss of one year of equivalent full health.

Quality Adjusted Life Years

Quality-adjusted life years, or QALYs, is a way of measuring disease burden, including both the quality and the quantity of life lived, as a means of quantifying in benefit of a medical intervention. The QALY model requires utility independent, risk neutral, and constant proportional tradeoff behaviour. [Pliskin, Shepard and Weinstein (1980, Operations Research)] 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.

Morbidity Measures

Morbidity measure include incidence rate, prevalence and cumulative incidence. Incidence rate is the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator.

Health conditions

HIV/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.

= Nutrition = An individual’s nutrition not only affects their health, but their ability to survive, their cognitive development and their work capacityFact|date=June 2008.

Among children under the age of five in the developing world, malnutrition contributes to 53% of deaths associated with infectious diseases. [WHO Nutrition http://www.who.int/nutrition/challenges/en/index.html] 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.

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 [Diarrhoeal Diseases based on UNICEF statistics http://www.childinfo.org/eddb/Diarrhoea/index.htm] . 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.

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

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.

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.

Infant and Child 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.“Child Mortality”, UNICEF Statistics, http://childinfo.org/areas/childmortality/.]

References

External links

* [http://www.dcp2.org/ Disease Control Priorities Project (DCPP)]
* [http://www.globalhealth.org/ Global Health Council]
* [http://www.globalhealthreporting.org/ Global Health Reporting (Kaiser Family Foundation)]
* [http://www.wilsoncenter.org/index.cfm?fuseaction=topics.home&topic_id=116811 Global Health Initiative] (Woodrow Wilson International Center for Scholars)
* [http://cpmcnet.columbia.edu/dept/bgcu-md/ Medical School for International Health]
* [http://time.blogs.com/global_health/ Global Health Update (Time.com)]
* [http://www.lshtm.ac.uk/ London School of Hygiene and Tropical Medicine]
* [http://www.nitd.novartis.com/ Novartis Institute of Tropical Medicine (Singapore)]
* [http://www.scidev.net/ Science and Development Network]
* [http://www.worldhealthnews.harvard.edu/ World Health News (Harvard)]
* [http://www.who.int/ World Health Organization]
* [http://cgh.virginia.edu/ Center for Global Health at the University of Virginia]
* [http://www.actionforglobalhealth.eu Action for Global Health]
* [http://www.globalizationandhealth.com Globalization and Health]