Public Health: Core Concepts, System, and History (Study Notes)
Definitions and Core Concepts of Public Health
Working definition focus: public health arises from historical phenomena shaping its development; in the 21st century it is defined through multiple definitions, core functions, and the 10 Essential Public Health Services.
Key objectives of first chapters: articulate several definitions, describe origins/evolution, trace system development, characterize contributions/value, identify distinguishing features, emphasize core functions and 10 Essential Public Health Services, and locate useful public health information sources.
Winslow (1920) definition highlights: public health as science and art of preventing disease, prolonging life, and promoting health and efficiency through organized community effort; encompasses sanitation, control of communicable infections, education in personal hygiene, organization of medical/nursing services for early diagnosis and preventive treatment, and development of social machinery to ensure a standard of living adequate for health and longevity; warns against equating public health with pure police power.
NAM (1988) definition: public health’s mission is fulfilling society’s interest in assuring conditions in which people can be healthy; emphasizes social, environmental, economic, political, and medical care factors that influence health; sees public health as a system involving government and non-governmental partners; introduces three core functions and 10 Essential Public Health Services.
Public Health 3.0 (Public Health 1.0, 2.0, 3.0): three phases describing evolution from 1.0 (infectious disease control, environmental health, basic public health services) to 2.0 (systematic capacity-building, state/local agency development, calibration of programs) to 3.0 (cross-sector collaboration, attention to social determinants of health, policy/environmental/system-level actions).
Public health definitions (Table comparisons): several definitions align on prevention, conditions for health, and promotion of physical/mental health; they broaden beyond government action to include social determinants and collective action.
Public health as a system (Table/Figure): central governmental public health infrastructure coordinates data, evidence-based interventions, and acts as chief health strategist; surrounded by non-governmental sectors (environment, housing, healthcare delivery, employers, media, academia, philanthropy, community organizations, policy makers, and the community).
Public Health System diagram (1-4): core around government public health agencies; outer rings include non-health government agencies, healthcare delivery system, employers, media, academia, philanthropy, community organizations, and the public; One Health illustrates cross-sector collaboration for zoonoses and antimicrobial resistance across human, animal, and environmental health.
One Health: interdisciplinary collaboration across human/animal/environmental health; federal coordination among CDC, FDA, USDA, EPA; state/local integration; global considerations; examples include antimicrobial resistance linked to animal antibiotic use and waste disposal.
Social Ecological Model (Figure 1-5): centers on the individual; concentric layers show the influence of lifestyle, social networks, living/working conditions, and broader socio-economic, cultural, and environmental factors; public health action can target multiple levels, including upstream determinants.
Health in All Policies (HiAP): cross-governmental approach to evaluate health impacts of policies across sectors; aim to improve health outcomes via broader policy actions, not just health departments.
Health Impact Pyramid (Figure 1-6): framework for public health action with levels from base to top:
Base: Social and economic determinants of health; e.g., poverty, education, housing.
Next: Changing the context to make healthier default choices (e.g., smoke-free laws, water fluoridation, folic acid fortification, trans fat bans).
Middle: Long-lasting protective interventions (immunizations, screening, defense against risk factors).
Higher levels: Clinical preventive services (screenings, risk-factor management) and Counseling/Education (individual-level effort).
Emphasis: Interventions at lower levels can produce population-wide impact with less individual effort; higher levels require more targeted individual action.
Public health goals and outcomes: prevention-focused, aiming to reduce epidemics, environmental hazards, injuries; promote healthy behaviors; respond to disasters; ensure access to high-quality services; improve workforce competency; evaluate and adapt interventions; all while maintaining data-driven and evidence-based practices.
The Three Core Functions and the 10 Essential Public Health Services
NAM’s core functions (assessment, policy development, assurance) describe what public health does and the order: diagnose health problems (assessment) → develop policies to address them (policy development) → ensure services are provided/implemented (assurance) → re-assess health status and adjust (cyclical process).
Assessment (Core Function 1): regular, systematic collection/analysis of health status, needs, epidemiology; ensure accountability across agencies; cannot be delegated; may require intergovernmental cooperation.
Policy Development (Core Function 2): develop policies that promote population health; integrate scientific knowledge into decision making; operate within democratic processes for political support.
Assurance (Core Function 3): assure services through public/private actions, regulation, or direct provision; involve policymakers and the public in implementation decisions.
The 10 Essential Public Health Services (Table 1-3) map to these core functions:
Assessment: 1) Monitor health status; 2) Diagnose/investigate health problems.
Policy Development: 3) Inform/educate/empower; 4) Mobilize partnerships; 5) Develop policies/plans;
Assurance: 6) Enforce laws/regulations; 7) Link to services; 8) Ensure a competent workforce; 9) Evaluate effectiveness/ access/ quality.
Cross-cutting: 10) Research for new insights/innovative solutions.
The linkage between core functions and the 10 services is depicted in Figure 1-3, showing a cyclic process that continually identifies problems, crafts solutions, implements them, and reassesses.
These services guide the mission to promote physical/mental health and prevent disease, injury, and disability (Public Health in America framework).
Public Health in the United States: A Brief History
Early influences of epidemics: ancient/medieval disease viewed as supernatural; miasma theories; public health actions practical and rudimentary (sanitation, waste removal) before germ theory.
17th–18th centuries in the Americas: yellow fever epidemic in 1793 in Philadelphia prompted formation of a Board of Health; early local boards used police powers (evacuation, isolation, quarantine) and sanitation measures.
Germ theory and vaccination: Jenner’s smallpox vaccination (1796) led to eradication by 1977; Snow’s cholera work (1854 Broad Street pump) used descriptive epidemiology to identify source; the pump handle removed as a symbol of public health intervention; Koch's germ theory later. Snow’s systematic data collection contrasted with the General Board of Health’s less rigorous conclusions.
Mid- to late-1800s: Chadwick’s sanitary movement; focus on environment, sanitation, and structuring government roles; utilitarian view linked disease to poverty; led to creation of public health structures and the General Board of Health in 1848; debate about upstream social determinants versus pathophysiology persisted.
Lemuel Shattuck (1850) and the Massachusetts Sanitary Commission: called for state/local health departments, sanitary inspections, communicable disease control, food sanitation, vital statistics, and infant/child services; Winslow praised it as prophetic; state/local health departments expanded to include environmental controls, vaccination, and disease prevention.
Late 19th–early 20th centuries: emphasis on environmental controls (drinking water, sewage), vaccination, and disease-specific interventions; in the U.S., local health departments evolved and were supported by state-level boards; infectious disease control remained central through the early 20th century.
Farr and vital statistics: William Farr developed vital statistics systems (death certificates, causes of death) in England/Wales; debates over whether to classify deaths by pathologies or upstream factors continued.
20th century growth: infectious disease control and maternal/child health expanded public health, followed by recognition of chronic diseases (heart disease, cancer, stroke) and occupational hazards as public health concerns; the system broadened beyond infectious diseases.
Federal role development: Marine Hospital Service (1798) evolved into U.S. Public Health Service; post-16th Amendment (1916) enabled federal tax funding; grants-in-aid to states/localities began shaping federal involvement; Social Security Act (1935) broadened public health funding via economic supports; Hill-Burton Act (1946) funded hospital construction; Medicare/Medicaid established in 1966; postwar era expanded public health into broader areas beyond infectious disease.
Post-1980s NAM report and Public Health 1.0/2.0/3.0: NAM’s 1988 report highlighted lack of unified mission, governance tensions, weak demonstration of public health value, uneasy medicine-public health relationships, and under-resourced research; led to core functions and 10 essential services, accreditation efforts, and the evolution of public health practice.
Public Health 1.0 (late 1800s–1988): rapid growth of science, epidemiology, engineering, vaccinology; focus on infectious disease control and environmental health; uneven access to services.
Public Health 2.0 (circa 1988–2007/2009): systematic development of state/local public health capacity; focused programmatic funding (immunizations, infectious disease, chronic disease); national accreditation mechanism (2007) prepared for modernization; funding swings and recession impacts.
Public Health 3.0 (2016–present): cross-sector collaboration, HiAP, addressing social determinants of health, leadership in the community as Chief Health Strategist, formal accreditation emphasis, data transparency, and innovative funding models; the ACA reduced gap-filling medical service demands, allowing more focus on upstream determinants and equity.
External prompts: ACA (2010) expanded insurance access; NAM and successive reports emphasized social determinants and coordinated cross-sector leadership; the evolution continues with new funding, data, and equity-focused initiatives.
The Public Health System and Its Sectors
The NAM framework defines the public health system as including government public health agencies and non-governmental actors across sectors that influence health.
The central public health infrastructure (local/state/federal agencies) coordinates data, evidence-based interventions, and serves as chief health strategist for communities.
Surrounding sectors include: other government agencies (environment, housing), healthcare delivery system, employers/workplaces, media, academia, philanthropy, community organizations, and the community itself.
One Health: cross-sector collaboration across human, animal, and environmental health; shared biosurveillance to track pathogens across species and environment; key agencies: CDC, FDA, USDA, EPA; state/local counterparts; global coordination for local control of antimicrobial resistance.
The Social Ecological Model (Figure 1-5) provides a framework to analyze determinants of health across four concentric layers: individual, social networks, living/working conditions, and general socio-economic/cultural/environmental conditions.
Health in All Policies (HiAP): implementing health considerations across government policy-making to improve population health outcomes by engaging multiple sectors.
The Health Impact Pyramid and Prevention Framework
Health Impact Pyramid (Figure 1-6) shows levels of intervention from population-wide determinants to individual counseling:
Base: address broad socio-economic determinants (poverty, education, housing) and create environments that enable healthy choices.
Next: changes to context to default healthier choices (smoke-free laws, water fluoridation, folic acid fortification, trans fat bans).
Middle: long-lasting protective interventions (immunizations, preventive screenings, risk-factor reduction) with broad population impact.
Higher: clinical preventive services (screenings, treatment of risk factors such as high blood pressure, high cholesterol).
Top: counseling/education (individual-level advice).
Public health action emphasis: interventions at the base can yield broad population benefits with less individual effort; higher levels require more targeted interventions and greater effort per person.
HI-5 initiative (CDC): focus on high-impact, evidence-based interventions in the first two levels of the pyramid to maximize population health gains within five years.
The Three Buckets of Prevention (CDC framework):
Bucket 1: clinical preventive services implemented in healthcare settings (e.g., screenings).
Bucket 2: non-clinical services outside the clinic (e.g., home visits for asthma management, environmental modifications).
Bucket 3: community-wide population interventions (e.g., safe spaces for physical activity, access to healthy foods).
ROI for prevention: Trust for America’s Health analysis showing potential return on investment for evidence-based community prevention programs; estimates include an ROI of 1.4:1 in 1 year and 7:1 in 5 years.
National Prevention Strategy (2011): seven priority areas (Tobacco-free living; Preventing drug abuse and excessive alcohol use; Healthy eating; Active living; Injury and violence-free living; Reproductive and sexual health; Mental/emotional well-being) and four strategic domains (Healthy and Safe Community Environments; Clinical and Community Preventive Services; Empowered People; Elimination of health disparities).
Characteristics of a Public Health Approach
Public health is grounded in science and relies on epidemiology/biostatistics and social/behavioral/economic sciences; evidence-based practice is supported by advisory bodies (e.g., US Preventive Services Task Force, ACIP, Community Preventive Services Task Force, HICPAC).
Public health is focused on prevention as a primary strategy; it targets multiple outcomes and scales from individual to population level; it also addresses unseen benefits of prevention (e.g., diseases prevented by vaccination are not observed in those who are not infected).
Public health is founded on social justice and health equity philosophies; health is considered a human right (WHO Constitution); equity requires addressing social determinants and ensuring fair opportunities to be healthy.
Public health is ethical and principled (Table 1-7): 12 principles guiding ethical practice (e.g., address fundamental causes of disease; respect rights; involve community; empower disenfranchised groups; obtain informed input; ensure consent; act timely; respect diverse values; protect confidentiality; ensure professional competence; collaborate to build public trust).
Public health is closely linked with government; government acts as regulator/enforcer and funder, convenor, and data-driven policymaker; HiAP emphasizes cross-agency collaboration; funding challenges reflect political and budgetary realities, including the need to demonstrate value and outcomes.
Public health is inherently political because of its social justice orientation; debates around “market justice” vs. “social justice” influence public health policy and financing (e.g., ACA debates, prevention funding, and resource allocation).
Public health relies on a broad, multidisciplinary workforce; while not all public health workers hold formal public health degrees, the field embraces diverse professionals bound by common goals; there is movement toward standardized accreditation and professionalization (e.g., Certified in Public Health credential, CEPH accreditation).
The public health agenda is dynamic and expanding to address new challenges (e.g., bioterrorism preparedness, opioid epidemic, climate-related health effects, antimicrobial resistance).
The Value of Public Health and the Achievements of the 20th Century
Ten Great Public Health Achievements (1900–1999) include: Vaccination; Motor-vehicle safety; Safer workplaces; Control of infectious diseases; Decline in deaths from coronary heart disease and stroke; Safer and healthier foods; Healthier mothers and babies; Family planning; Fluoridation of drinking water; Recognition of tobacco use as a health hazard.
Impact on life expectancy and mortality:
Public health prevention is responsible for about 25 years of the nearly 30-year increase in life expectancy at birth since 1900; only about 5 years attributed to medical care improvements; of those 5 years, about 3.7 years from medical treatment and 1.5 years from clinical preventive services.
Studies in England/Wales (1981–2000) show 79% of life-years gained were due to reductions in major risk factors, with 21% from medical/surgical treatments for coronary heart disease.
Measurable declines in infectious diseases due to vaccination and other public health efforts contributed to large health gains; but policy and public attitudes toward vaccination can produce outbreaks if uptake declines (e.g., post-1999 vaccines discussions).
Public health value to the public: public opinion polls generally show high value placed on public health; however, public support for funding varies by issue and is often politically polarized; the public recognizes the importance of public health, particularly in addressing chronic disease, infectious disease threats, and disaster preparedness, though funding levels may be contested.
The Public Health Challenges, Ethics, and the Policy Landscape
The NAM’s 1988 report highlighted critical issues: lack of clear mission, political-professional tensions, weak demonstration of public health value to legislators/public, uneasy relationships with medicine, and under-resourced research.
The field must balance political realities with ethical commitments; public health decisions often require trade-offs and compelling arguments for prevention investments.
The relationship with government is central to public health, including enforcement powers and budgetary decisions; the sustainability of funding can be volatile and tied to current crises or political will.
The opioid epidemic and other contemporary public health crises illustrate ongoing challenges and the need for sustained funding and cross-sector collaboration to address complex determinants of health.
Ethical principles and governance: the field maintains a formal code of ethics to prevent abuses of power and to protect confidentiality, ensure representative input, and promote equity.
Outside-the-Book Thinking and Discussion Prompts
Outside-the-Book Thinking 1-1: Access Delta Omega’s public health documents and describe a classic historical public health document’s significance and relevance today.
Outside-the-Book Thinking 1-2: Research your state/county/city public health department history; identify its establishment year; discuss how problems and strategies have changed; note recent news coverage and current roles.
Outside-the-Book Thinking 1-3: Read Winslow’s 1920 speech and reflect on recommended improvements and what still rings true today.
Outside-the-Book Thinking 1-4: Review public health definitions (Table 1-2, 1-3) and discuss strengths/limitations of each as descriptors of public health today; align with the public health system perspective.
Outside-the-Book Thinking 1-5: Evaluate a major public health journal’s table of contents; examine a paper on a public health intervention; assess the strength of evidence and readiness for community implementation.
Outside-the-Book Thinking 1-6: Describe the role of at least one sector of the public health system in promoting health; explain how it provides unique contributions; discuss its interaction with governmental public health infrastructure.
Outside-the-Book Thinking 1-7: Review CDC’s One Health resources and summarize measures addressing antimicrobial resistance in humans, animals, and the environment; identify state-level applications.
Outside-the-Book Thinking 1-8: Map local/state agencies and propose how each could contribute to a Health in All Policies approach for a local issue (e.g., obesity, asthma, substance use).
Outside-the-Book Thinking 1-9: Explore public health advisory committees’ meetings to observe how evidence-based practices are debated and integrated into recommendations.
Outside-the-Book Thinking 1-10: Examine three levels of the Health Impact Pyramid in a real-world case and discuss how upstream determinants could be addressed in practice.
Discussion Questions (from Chapter)
Pick a major historical public health figure mentioned in the chapter. What was their most important contribution? Why is it important, and what is their enduring legacy?
How do the characteristic features of a public health approach distinguish it from other fields or not? Consider science, prevention, social justice, ethics, government linkages, HiAP, multidisciplinary culture, and dynamism.
Review recent news headlines related to health. How many focus on public health versus health care? How is prevention highlighted? Is health equity addressed? What other themes appear?
Key Definitions and Tables to Reference
Winslow (1920): The Untilled Fields of Public Health – long-form definition emphasizing science/arts, organized community effort, environmental sanitation, infection control, education, medical services, and social machinery for health living rights.
NAM (1988) Definition of Public Health: Fulfilling society’s interest in assuring conditions for health; three core functions (Assessment, Policy Development, Assurance) and 10 Essential Public Health Services.
Table 1-2 Selected Definitions of Public Health (example entries):
Public health as the science and art of preventing disease, prolonging life, and promoting health and efficiency through organized community effort.
Public health as fulfilling society’s interest in assuring conditions in which people can be healthy.
Public health as promoting physical and mental health and preventing disease, injury, and disability.
Table 1-3 Public Health in America – Core functions (Assessment, Policy Development, Assurance) with the 10 Essential Public Health Services mapped to each core function.
Table 1-4 Understandings of Public Health – Public Health as a profession, methods, government/public health services, health of the public, and the system/social enterprise.
Table 1-5 Selected Characteristics of a Public Health Approach (science-based, prevention-focused, social justice, ethics, government linkage, HiAP, multidisciplinary culture, dynamic agenda).
Table 1-7 Ethical Principles of Public Health (12 principles, including respect for rights, community input, empowerment of disenfranchised groups, confidentiality, competence, and trust-building).
Table 1-8 Ten Great Public Health Achievements (1900–1999): vaccination, motor-vehicle safety, safer workplaces, control of infectious diseases, decline in coronary heart disease and stroke, safer/healthier foods, healthier mothers and babies, family planning, fluoridation of drinking water, recognition of tobacco as a health hazard.
Figure 1-3 Public Health Core Functions and 10 Essential Services (relationship/flow among assessment, policy development, and assurance, with the 10 services across the three functions).
Figure 1-4 The Public Health System (central governmental infrastructure with non-government sectors around it).
Figure 1-5 The Social Ecological Model of Determinants of Health (layers from individual to outer socio-economic/environmental conditions).
Figure 1-6 The Health Impact Pyramid (societal determinants to individual counseling).
Figure 1-7 The Three Buckets of Prevention (clinical, non-clinical outside clinic, community/population-wide interventions).
Notes: This compilation draws from the provided transcript to form a structured study-friendly set of notes. All numerical data, figures, and named concepts are included as described in the transcript. Where numerical values appear, they are represented in plain text here; LaTeX blocks are used in the body of the notes above for key numerical relationships (e.g., life expectancy changes, ROI figures, and large counts). For your exam, you can reference the LaTeX-formatted expressions directly in this note collection where appropriate.