Understanding Public Health: Definitions & Functions

What is Public Health?

• Public Health definition from 1920 by Charles-Edward A. Winslow defines it as the science and art of preventing disease, prolonging life, and promoting health through organized community efforts
• It promotes and protects the health of people and their communities.
• Those in public health work to prevent sickness and injury, while also promoting wellness.

What "Public" Means

• "Public" refers to a group as small as a local neighborhood, as large as an entire city, or even spanning continents in the case of a pandemic.

Definition of Health

• Health is defined by the World Health Organization as a state of complete physical, mental, and social well-being, not merely the absence of disease.

Core Functions of Public Health

• Assessment
• Policy Development
• Assurance

Essential Public Health Services

• Monitor health status to identify community health problems
• Diagnose and investigate health problems and hazards
• Inform, educate, and empower people about health issues
• Mobilize community partnerships to solve health problems
• Develop policies and plans to support health efforts
• Enforce laws and regulations to protect health and ensure safety
• Link people to needed health services
• Assure a competent public health workforce
• Evaluate effectiveness, accessibility, and quality of health services
• Research for innovative solutions to health problems

Public Health as a Coalition

• The Institute of Medicine defines public health as a coalition of professions with a shared mission focused on disease prevention and health promotion.

Public Health as an Interdisciplinary Field

• Epidemiology
• Biostatistics
• Social Sciences
• Management of Health Services
• Environmental Health
• Community Health
• Behavioral Health
• Health Economics
• Public Policy
• Mental Health
• Health Education
• Health Politics
• Occupational Safety
• Disability, Oral Health
• Gender Issues
• Sexual and Reproductive Health

Disciplines of Public Health

• Epidemiology
• Statistics
• Biomedical Sciences
• Social and Behavioral Sciences
• Environmental Sciences
• Health Management and Policy

Epidemiology

• Called the basic science of public health.
• It is the study of epidemics and populations to find the causes of health and disease.
• It provides early indications of new diseases, like AIDS in the 1980s.
• Important to note it can also identify causes of chronic issues, like heart disease or cancer.

Statistics

• Involves collecting and analyzing data, finding causation, and calculating probabilities.
• Public health relies heavily on statistics because it deals with the health of populations.
• Governments collect data on births, deaths, disease outbreaks, cancer cases, occupational injuries, and other health issues to understand societal health.
• Statistical analysis is essential for epidemiological and clinical studies.

Biomedical Science

• Involves studying the biological basis of human health and disease, including genetics, immunology, infectious diseases, chronic diseases, and molecular approaches to treatment.
• Public health and medicine depend on these sciences.
• Understanding the spread and effect of infectious agents is crucial for prevention and control.
• Biomedical research identifies major killers, enabling public health measures.

Environmental Health

• Concerned with preventing the spread of disease through water, air, and food.
• It shares concerns with biomedical sciences regarding infectious organisms.
• Epidemiology tracks environmental causes of disease outbreaks in the field.
• While considered a separate area, there is an overlap.

Modern Environmental Health Challenges

• New challenges to environmental health continue to emerge.
• Modern lifestyles create new problems like air and water pollution.
• Thousands of new chemicals enter the environment annually.
• Toxic chemicals accumulate, requiring safe disposal methods.
• Environmental threats include ultraviolet rays and radiation.
• Human activities alter Earth's climate.

Social and Behavioral Sciences

• Focuses on human behavior and involves careful analysis of human behavior including social psychology.
• Consists of anthropology, economics, history, political science, and sociology.
• Behavioral focus is understanding, predicting, and influencing behavior, so includes anthropology, psychology, and sociology.
• Modern diseases are often caused by behavior and the social environment.

Examples of Social and Behavioral Problems

• Heart disease is related to nutrition and exercise patterns.
• Many forms of cancer are caused by smoking.
• Abuse of drugs and alcohol is a leading cause of death.
• Violence is a significant cause of death.

Health Management and Policy

• Includes the administration and functioning of the public health system.
• Public health depends on politics for decision making.
• Community interventions requiring government action are reached through politics.

Public Health vs. Medical Care

• Medicine focuses on individual patients, while public health concerns itself with the community as its patient, aiming to improve the health of the entire population.
• Medicine focuses on healing patients, while public health focuses on preventing illness.

Public Health Functions Compared with Medical Care

• Assessment is the diagnostic function, where information on population health is collected and analyzed, similarly to a doctor assessing a patient.
• Policy development is like a doctor creating a treatment plan, involving the use of scientific knowledge to develop strategies for improving community health.
• Assurance is equivalent to a doctor's treatment of a patient.

"Silence" of Public Health

• Public health's focus on prevention is more abstract than medicine, making achievements harder to recognize.
• This lack of recognition results in less attention from politicians and the public compared to medical care.

Political Decisions in Public Health

• Public health is based on science, yet often requires political decisions before action.
• Unlike a doctor-patient relationship where the patient can accept or reject treatment, in public health, the government makes decisions on community health recommendations.

Prevention and Intervention

• Public health addresses issues in a five-step process.
• First, define the health problem.
• Second, identify risk factors.
• Third, develop and test interventions.
• Fourth, implement interventions.
• Fifth, monitor to assess effectiveness.

Intervention

• It is a generic term in public health describing a program or policy designed to impact a health problem.
• Different interventions exist for levels of prevention.
• The three levels of prevention include primary, secondary, and tertiary.

Primary Prevention

• Prevents an illness or injury by preventing exposure to risk factors, i.e., preventing the onset of disease or injury.
• Interventions to prevent cancer include discouraging teenagers from smoking and encouraging current smokers to quit.
• Immunizations are a form of primary prevention.

Secondary Prevention

• Seeks to minimize the severity of illness, or damage due to an injury, once it has occurred.
• Interventions include screening programs to detect cancer early.

Tertiary Prevention

• Seeks to minimize disability by providing medical care and rehabilitation services.
• Involves medical treatment and rehabilitation of cancer patients.

Chain of Causation Model (Epidemiological Triad)

• It is an approach to designing interventions thinking of illness or injury as a chain of causation.
• The model involves an agent, a host, and the environment.
• Applied to infectious diseases, the triad includes a disease-causing bacterium or virus (agent), a susceptible human being (host), and a transmission means (environment).

Prevention and Causation

• Prevention is accomplished by interrupting the chain of causation at any step.
• Examples include: Rendering a potential host unsusceptible through immunization, killing a bacterium with antibiotics, or sanitizing contaminated water and food.

In Conclusion

• The goal of public health is maximum health for all.
• Public health is concerned with the prevention of disease and disability, aiming to benefit the entire population (in contrast to medicine, which focuses on the individual).
• Public health diagnoses and treats community issues through assessment, policy development, and assurance.
• It relies on science and politics.
• Public health depends on political decision making for interventions requiring government action.