Public health

Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the determinants of health of a population and the threats it faces is the basis for public health. The ''public'' can be as small as a handful of people or as large as a village or an entire city; in the case of a pandemic it may encompass several continents. The concept of ''health'' takes into account physical, psychological, and social well-being.What is the WHO definition of health?
from the Preamble to the Constitution of WHO as adopted by the International Health Conference, New York, 19 June - 22 July 1946; signed on 22 July 1946 by the representatives of 61 States (Official Records of WHO, no. 2, p. 100) and entered into force on 7 April 1948. The definition has not been amended since 1948.

Public health is an interdisciplinary field. For example, epidemiology, biostatistics, social sciences and management of health services are all relevant. Other important sub-fields include environmental health, community health, behavioral health, health economics, public policy, mental health, health education, health politics, occupational safety, disability, oral health, gender issues in health, and sexual and reproductive health. Public health, together with primary care, secondary care, and tertiary care, is part of a country's overall health care system. Public health is implemented through the surveillance of cases and health indicators, and through the promotion of healthy behaviors. Common public health initiatives include promotion of hand-washing and breastfeeding, delivery of vaccinations, promoting ventilation and improved air quality both indoors and outdoors, suicide prevention, smoking cessation, obesity education, increasing healthcare accessibility and distribution of condoms to control the spread of sexually transmitted diseases.

There is a significant disparity in access to health care and public health initiatives between developed countries and developing countries, as well as within developing countries. In developing countries, public health infrastructures are still forming. There may not be enough trained healthcare workers, monetary resources, or, in some cases, sufficient knowledge to provide even a basic level of medical care and disease prevention. A major public health concern in developing countries is poor maternal and child health, exacerbated by malnutrition and poverty coupled with governments' reluctance in implementing public health policies.

From the beginnings of human civilization, communities promoted health and fought disease at the population level. In complex, pre-industrialized societies, interventions designed to reduce health risks could be the initiative of different stakeholders, such as army generals, the clergy or rulers. Great Britain became a leader in the development of public health initiatives, beginning in the 19th century, due to the fact that it was the first modern urban nation worldwide. The public health initiatives that began to emerge initially focused on sanitation (for example, the Liverpool and London sewerage systems), control of infectious diseases (including vaccination and quarantine) and an evolving infrastructure of various sciences, e.g. statistics, microbiology, epidemiology, sciences of engineering.

Definitions and purposes

Definition

Public health has been defined as "the science and art of preventing disease", prolonging life and improving quality of life through organized efforts and informed choices of society, organizations (public and private), communities and individuals. The ''public'' can be as small as a handful of people or as large as a village or an entire city. The concept of ''health'' takes into account physical, psychological, and social well-being. As such, according to the World Health Organization, "health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity".

Related terms

Public health is related to global health which is the health of populations in the worldwide context. 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". International health is a field of health care, usually with a public health emphasis, dealing with health across regional or national boundaries. Public health is not the same as public healthcare ( publicly funded health care).

The term preventive medicine is related to public health. The American Board of Preventive Medicine separates three categories of preventive medicine: aerospace health, occupational health, and public health and general preventative medicine. Jung, Boris and Lushniak argue that preventive medicine should be considered the medical specialty for public health but note that the American College of Preventive Medicine and American Board of Preventive Medicine do not prominently use the term "public health". Preventive medicine specialists are trained as clinicians and address complex health needs of a population such as by assessing the need for disease prevention programs, using the best methods to implement them, and assessing their effectiveness.

Since the 1990s many scholars in public health have been using the term population health. There are no medical specialties directly related to population health. Valles argues that consideration of health equity is a fundamental part of population health. Scholars such as Coggon and Pielke express concerns about bringing general issues of wealth distribution into population health. Pielke worries about "stealth issue advocacy" in population health. Jung, Boris and Lushniak consider population health to be a concept that is the goal of an activity called public health practiced through the specialty preventive medicine.

Lifestyle medicine uses individual lifestyle modification to prevent or revert disease and can be considered a component of preventive medicine and public health. It is implemented as part of primary care rather than a specialty in its own right. Valles argues that the term social medicine has a narrower and more biomedical focus than the term population health.

Purposes

The purpose of a public health intervention is to prevent and mitigate diseases, injuries and other health conditions. The overall goal is to improve the health of populations and increase life expectancy.

Characteristics and components

Public health is a complex term, composed of many elements and different practices. It is a multi-faceted, interdisciplinary field. For example, epidemiology, biostatistics, social sciences and management of health services are all relevant. Other important sub-fields include environmental health, community health, behavioral health, health economics, public policy, mental health, health education, health politics, occupational safety, disability, gender issues in health, and sexual and reproductive health.

Modern public health practice requires multidisciplinary teams of public health workers and professionals. Teams might include epidemiologists, biostatisticians, physician assistants, public health nurses, midwives, medical microbiologists, pharmacists, economists, sociologists, geneticists, data managers, environmental health officers ( public health inspectors), bioethicists, gender experts, sexual and reproductive health specialists, physicians, and veterinarians.

The elements and priorities of public health have evolved over time, and are continuing to evolve. Different regions in the world can have different public health concerns at a given time.

Common public health initiatives include promotion of hand-washing and breastfeeding, delivery of vaccinations, suicide prevention, smoking cessation, obesity education, increasing healthcare accessibility and distribution of condoms to control the spread of sexually transmitted diseases.

Methods

Public health aims are achieved through surveillance of cases and the promotion of healthy behaviors, communities and environments. Analyzing the determinants of health of a population and the threats it faces is the basis for public health.

Many diseases are preventable through simple, nonmedical methods. For example, research has shown that the simple act of handwashing with soap can prevent the spread of many contagious diseases. In other cases, treating a disease or controlling a pathogen can be vital to preventing its spread to others, either during an outbreak of infectious disease or through contamination of food or water supplies. Public health communications programs, vaccination programs and distribution of condoms are examples of common preventive public health measures.

Public health, together with primary care, secondary care, and tertiary care, is part of a country's overall health care system. Many interventions of public health interest are delivered outside of health facilities, such as food safety surveillance, distribution of condoms and needle-exchange programs for the prevention of transmissible diseases.

Public health plays an important role in disease prevention efforts in both the developing world and in developed countries through local health systems and non-governmental organizations.

Public health requires Geographic Information Systems (GIS) because risk, vulnerability and exposure involve geographic aspects.

Ethics

A dilemma in public health ethics is dealing with the conflict between individual rights and maximizing right to health. Public health is justified by consequentialist utilitarian ideas, but is constrained and critiqued by liberal, deontological, principlist and libertarian philosophies Stephen Holland argues that it can be easy to find a particular framework to justify any viewpoint on public health issues, but that the correct approach is to find a framework that best describes a situation and see what it implies about public health policy.

The definition of health is vague and there are many conceptualizations. Public health practitioners definition of health can different markedly from members of the public or clinicians. This can mean that members of the public view the values behind public health interventions as alien which can cause resentment amongst the public towards certain interventions. Such vagueness can be a problem for health promotion. Critics have argued that public health tends to place more focus on individual factors associated with health at the expense of factors operating at the population level.

Historically, public health campaigns have been criticized as a form of "healthism", as moralistic in nature rather than being focused on health. Medical doctors, Petr Shkrabanek and James McCormick wrote a series of publications on this topic in the late 1980s and early 1990s criticizing the UK's ''the Health of The Nation'' campaign. These publications exposed abuse of epidemiology and statistics by the public health movement to support lifestyle interventions and screening programs. A combination of inculcating a fear of ill-health and a strong notion of individual responsibility has been criticized as a form of "health fascism" by a number of scholars, objectifying the individual with no considerations of emotional or social factors.

Priority areas

Original focal areas

When public health initiatives began to emerge in England in modern times (18th century onwards) there were three core strands of public health which were all related to statecraft: Supply of clean water and sanitation (for example London sewerage system); control of infectious diseases (including vaccination and quarantine); an evolving infrastructure of various sciences, e.g. statistics, microbiology, epidemiology, sciences of engineering. Great Britain was a leader in the development of public health during that time period out of necessity: Great Britain was the first modern urban nation (by 1851 more than half of the population lived in settlements of more than 2000 people). This led to a certain type of distress which then led to public health initiatives. Later that particular concern faded away.

Changing and differing focal areas

With the onset of the epidemiological transition and as the prevalence of infectious diseases decreased through the 20th century, public health began to put more focus on chronic diseases such as cancer and heart disease. Previous efforts in many developed countries had already led to dramatic reductions in the infant mortality rate using preventive methods. In Britain, the infant mortality rate fell from over 15% in 1870 to 7% by 1930.

A major public health concern in developing countries is poor maternal and child health, exacerbated by malnutrition and poverty. The WHO reports that a lack of exclusive breastfeeding during the first six months of life contributes to over a million avoidable child deaths each year.

Public health surveillance has led to the identification and prioritization of many public health issues facing the world today, including HIV/AIDS, diabetes, waterborne diseases, zoonotic diseases, and antibiotic resistance leading to the reemergence of infectious diseases such as tuberculosis. Antibiotic resistance, also known as drug resistance, was the theme of World Health Day 2011.

For example, the WHO reports that at least 220 million people worldwide have diabetes. Its incidence is increasing rapidly, and it is projected that the number of diabetes deaths will double by 2030. In a June 2010 editorial in the medical journal '' The Lancet'', the authors opined that "The fact that type 2 diabetes, a largely preventable disorder, has reached epidemic proportion is a public health humiliation." The risk of type 2 diabetes is closely linked with the growing problem of obesity. The WHO's latest estimates highlighted that globally approximately 1.9 billion adults were overweight in 2014, and 41 million children under the age of five were overweight in 2014. Once considered a problem in high-income countries, it is now on the rise in low-income countries, especially in urban settings.

Many public health programs are increasingly dedicating attention and resources to the issue of obesity, with objectives to address the underlying causes including healthy diet and physical exercise. The National Institute for Health and Care Research (NIHR) has published a review of research on what local authorities can do to tackle obesity. The review covers interventions in the food environment (what people buy and eat), the built and natural environments, schools, and the community, as well as those focussing on active travel, leisure services and public sports, weight management programmes, and system-wide approaches.

Current practice

Organizations

World Health Organization (WHO)

The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution, which establishes the agency's governing structure and principles, states its main objective as "the attainment by all peoples of the highest possible level of health". The WHO's broad mandate includes advocating for universal healthcare, monitoring public health risks, coordinating responses to health emergencies, and promoting human health and well-being. The WHO has played a leading role in several public health achievements, most notably the eradication of smallpox, the near- eradication of polio, and the development of an Ebola vaccine. Its current priorities include communicable diseases, particularly HIV/AIDS, Ebola, COVID-19, malaria and tuberculosis; non-communicable diseases such as heart disease and cancer; healthy diet, nutrition, and food security; occupational health; and substance abuse.

Others

Most countries have their own governmental public health agency, often called the ministry of health, with responsibility for domestic health issues.

For example, in the United States, state and local health departments are on the front line of public health initiatives. In addition to their national duties, the United States Public Health Service (PHS), led by the Surgeon General of the United States Public Health Service, and the Centers for Disease Control and Prevention, headquartered in Atlanta, are also involved with international health activities.

Public health programs

Most governments recognize the importance of public health programs in reducing the incidence of disease, disability, and the effects of aging and other physical and mental health conditions. However, public health generally receives significantly less government funding compared with medicine. Although the collaboration of local health and government agencies is considered best practice to improve public health, the pieces of evidence available to support this is limited. Public health programs providing vaccinations have made major progress in promoting health, including substantially reducing the occurrence of cholera and polio and eradicating smallpox, diseases that have plagued humanity for thousands of years.

The World Health Organization (WHO) identifies core functions of public health programs including:
* providing leadership on matters critical to health and engaging in partnerships where joint action is needed;
* shaping a research agenda and stimulating the generation, translation and dissemination of valuable knowledge;
* setting norms and standards and promoting and monitoring their implementation;
* articulating ethical and evidence-based policy options;
* monitoring the health situation and assessing health trends.

In particular, public health surveillance programs can:
* serve as an early warning system for impending public health emergencies;
* document the impact of an intervention, or track progress towards specified goals; and
* monitor and clarify the epidemiology of health problems, allow priorities to be set, and inform health policy and strategies.
* diagnose, investigate, and monitor health problems and health hazards of the community

Behavior change

Many health problems are due to maladaptive personal behaviors. From an evolutionary psychology perspective, over consumption of novel substances that are harmful is due to the activation of an evolved reward system for substances such as drugs, tobacco, alcohol, refined salt, fat, and carbohydrates. New technologies such as modern transportation also cause reduced physical activity. Research has found that behavior is more effectively changed by taking evolutionary motivations into consideration instead of only presenting information about health effects. The marketing industry has long known the importance of associating products with high status and attractiveness to others. Films are increasingly being recognized as a public health tool. In fact, film festivals and competitions have been established to specifically promote films about health. Conversely, it has been argued that emphasizing the harmful and undesirable effects of tobacco smoking on other persons and imposing smoking bans in public places have been particularly effective in reducing tobacco smoking.

Applications in health care

As well as seeking to improve population health through the implementation of specific population-level interventions, public health contributes to medical care by identifying and assessing population needs for health care services, including:
* Assessing current services and evaluating whether they are meeting the objectives of the health care system
* Ascertaining requirements as expressed by health professionals, the public and other stakeholders
* Identifying the most appropriate interventions
* Considering the effect on resources for proposed interventions and assessing their cost-effectiveness
* Supporting decision making in health care and planning health services including any necessary changes.
* Informing, educating, and empowering people about health issues

Conflicting aims

Some programs and policies associated with public health promotion and prevention can be controversial. One such example is programs focusing on the prevention of HIV transmission through safe sex campaigns and needle-exchange programs. Another is the control of tobacco smoking. Changing smoking behavior requires long-term strategies, unlike the fight against communicable diseases, which usually takes a shorter period for effects to be observed. Many nations have implemented major initiatives to cut smoking, such as increased taxation and bans on smoking in some or all public places. Supporters argue by presenting evidence that smoking is one of the major killers, and that therefore governments have a duty to reduce the death rate, both through limiting passive (second-hand) smoking and by providing fewer opportunities for people to smoke. Opponents say that this undermines individual freedom and personal responsibility, and worry that the state may be encouraged to remove more and more choice in the name of better population health overall.

Psychological research confirms this tension between concerns about public health and concerns about personal liberty: (i) the best predictor of complying with public health recommendations such as hand-washing, mask-wearing, and staying at home (except for essential activity) during the COVID-19 pandemic was people's perceived duties to prevent harm but (ii) the best predictor of flouting such public health recommendations was valuing liberty more than equality.

Simultaneously, while communicable diseases have historically ranged uppermost as a global health priority, non-communicable diseases and the underlying behavior-related risk factors have been at the bottom. This is changing, however, as illustrated by the United Nations hosting its first General Assembly Special Summit on the issue of non-communicable diseases in September 2011.

Global perspectives

Disparities in service and access

There is a significant disparity in access to health care and public health initiatives between developed countries and developing countries, as well as within developing countries. In developing countries, public health infrastructures are still forming. There may not be enough trained health workers, monetary resources or, in some cases, sufficient knowledge to provide even a basic level of medical care and disease prevention. As a result, a large majority of disease and mortality in developing countries results from and contributes to extreme poverty