Modeling Determinants of Population Health

Chapter 4
Eric Delmelle
October 2, 7 2025

Chapter Overview

  • Understanding why some people are healthier than others is a core focus of public health.
  • Health is shaped by multiple factors, including:
    • Genetics
    • Lifestyle choices
    • Environment
    • Social conditions
  • This presentation explores models explaining how determinants interact to influence population health.

What are determinants of health?

  • Determinants of health are factors that influence an individual’s or a population’s health.
  • These determinants are often categorized into five key groups.
  • Understanding these determinants helps in designing effective health policies and interventions.

Biological and Genetic Determinants

  • Genetics: Inherited traits that influence susceptibility to diseases (e.g., family history of diabetes or heart disease).
  • Biological Factors: Age, sex, and genetic conditions (e.g., Down syndrome, cystic fibrosis).
  • Example: A person with a genetic predisposition to high cholesterol may develop heart disease if environmental and behavioral factors also contribute.

Behavioral Determinants

  • Individual lifestyle choices that impact health.
  • Key behaviors include:
    • Diet and Nutrition: Poor diet leads to obesity and related diseases.
    • Physical Activity: Lack of exercise increases risk for cardiovascular diseases.
    • Substance Use: Tobacco, alcohol, and drug use significantly affect health outcomes.
  • Example: Smoking is a leading cause of lung cancer and heart disease.

Social and Economic Determinants

  • Education and Income: Higher levels of education correlate with better health outcomes.
  • Employment and Working Conditions: Stable employment provides income and health benefits.
  • Social Support Networks: Strong community ties improve mental and physical health.
  • Example: Individuals in low-income communities often have limited access to healthy foods and healthcare services.

Environmental Determinants

  • Physical Environment: Pollution, climate change, and access to clean water affect health.
  • Built Environment: Availability of sidewalks, parks, and grocery stores.
  • Housing Conditions: Overcrowding and poor sanitation increase disease risks.
  • Example: High air pollution in urban areas is linked to increased rates of asthma and respiratory diseases.

Healthcare Access and Quality

  • Availability of Healthcare Services: Lack of access to preventive and emergency care worsens health disparities.
  • Health Insurance: Affects affordability of medical care.
  • Cultural Competency: Healthcare providers must address diverse patient needs.
  • Example: Rural communities often experience healthcare shortages, leading to untreated conditions.

Why Do We Need Health Determinant Models?

  • Health is not just about treating diseases—it’s about preventing them.
  • Important questions:
    • Why do wealthier neighborhoods have better health outcomes?
    • Why are chronic diseases more common in certain groups?
    • How do stress and social support affect mental health?
  • Traditional biomedical models focus on treatment, but population health considers broader social and environmental causes.

1 The Epidemiologic Triad

1 The Epidemiologic Triad

  • A basic model for infectious diseases with three components:

    1. Host – Individual or population affected.
    2. Agent – Disease-causing factor (e.g., bacteria, viruses, smoking).
    3. Environment – External factors affecting exposure (e.g., air pollution, sanitation).

  • Example: Tuberculosis

    • Agent: Mycobacterium tuberculosis
    • Host: Weakened immunity due to malnutrition
    • Environment: Overcrowding increases risk

  • Limitation: Does not fully explain chronic diseases.

2 The Health Field Model

  • Shifted focus from infectious diseases to chronic conditions.
  • Identifies four major health determinants:
    1. Human Biology – Genetic and physiological factors.
    2. Lifestyle – Behaviors like smoking, diet, exercise.
    3. Environment – Social and physical surroundings.
    4. Healthcare System – Access and quality of medical care.

2 The Health Field Model

Example: Heart Disease

  • Lifestyle: Smoking, unhealthy diet.
  • Environment: Food deserts, limited access to healthy food.
  • Healthcare System: Focuses on treatment rather than prevention.
  • Biology: Family history of heart disease, genetic predisposition to high cholesterol

2 The Health Field Model

  • A more advanced model

3 The Socio-ecological model

3 The Socio-ecological model

  • Health is shaped at multiple levels:
    • Individual – Genetics, behavior.
    • Interpersonal – Family, social support.
    • Community – Schools, workplaces, healthcare access.
    • Societal – Laws, policies, economy.

Example: Obesity Prevention

  • Individual: Encouraging healthy diet.
  • Community: More grocery stores and parks.
  • Societal: Taxes on unhealthy foods.

4 The Life Course Perspective

4 The Life Course Perspective

  • Health is cumulative and shaped over a lifetime
  • Early-life exposures impact later health outcomes
  • Critical periods: Childhood, adolescence, pregnancy
  • Protective and risk factors evolve through different life stages

4 The Life Course Perspective

  • Examines how early-life experiences shape future health.
  • Key Concepts:
    1. Latency Effects – Early-life exposures impact adult health.
    2. Cumulative Effects – Stress builds up over time.
    3. Pathway Effects – Disadvantages in childhood limit future opportunities.

Example: Childhood Poverty & Health

  • Poor nutrition in childhood → Increased risk for diabetes, heart disease in adulthood.
  • Chronic stress affects brain development.

4 The Life Course Perspective

4 The Life Course Perspective

  • Can geographic information keep you healthy? youtube-link
  • Bill Davenhall from ESRI

5 Biopsychosocial Model

  • Health is influenced by biological, psychological, and social factors
  • Biological: Genetics, immune function, neurobiology
  • Psychological: Stress, behavior, cognition
  • Social: Environment, socioeconomic status, relationships
  • Interaction: These domains interact dynamically, shaping health outcomes

5 Biopsychosocial Model

Pathways from Determinants to Health Outcomes

  • Upstream Determinants (e.g., policy, environment) →
  • Intermediate Factors (e.g., behaviors, stress) →
  • Downstream Outcomes (e.g., disease, mortality)
  • Example: Socioeconomic Status → Diet & Stress → Cardiovascular Health

Pathway Analysis

  • How do various determinants interact to influence health outcomes?
  • Mediators: Factors that explain part of the relationship (e.g., stress mediates poverty → health)
  • Moderators: Factors that modify the strength of the relationship (e.g., social support buffers stress effects)
  • Example: Education → Health Literacy → Better Health Management

Pathway Analysis

Pathway Analysis

Pathway Analysis

Nonlinear Dynamics & Health

  • Health systems are complex and nonlinear
  • Feedback Loops:
    • Positive: Obesity → Inflammation → More Obesity
    • Negative: Stress → Social Support → Stress Reduction
  • Threshold Effects: Small changes can lead to sudden shifts
    • Example: Chronic stress accumulation suddenly leading to burnout or illness

Policy Implications & Future Directions

  • Health policies should be evidence-based and proactive.
  • Types of interventions:
    1. Upstream: Tackling root causes (e.g., poverty reduction).
    2. Midstream: Changing risk behaviors (e.g., smoking bans).
    3. Downstream: Treating diseases after they occur.

Conclusions

  • Health is shaped by multiple determinants, not just healthcare.
  • Interventions must be multi-level to be effective.
  • Understanding health models helps in designing better policies.

Reflection Questions:

    1. What social determinants impact your own health?
    1. How can policies create healthier communities?

Thank you!