Disease, Illness, and Sickness

• Disease is a biological or physical ailment affecting the body.
• Illness is an individual's perception of their own dysfunction.
• Sickness is the social recognition of a person's impairment.

Factors Causing Disease

• Germs
• Genetics
• Lifestyle
• Multifactorial causes include epigenetic or environmental factors.

Germ Theory of Disease

• Koch's postulates:
  • Germs present in those with disease, absent in those without.
  • Germs can be isolated/cultured from those with disease.
  • Germs cause disease when introduced to a healthy host.
  • Germs can be re-isolated from the newly diseased host.
• Lister's work:
  • Sepsis may be caused by dust contaminating surgical wounds.
  • Antiseptic conditions (carbolic acid) prevent wound infections.
  • Surgical mortality fell from 45% to 15% after antiseptic intervention.
• Pasteur:
  • First postulated germ theory of disease.
  • Discovered microbial fermentation and sterilization principles.
  • Invented pasteurization of milk and wine.

Genetic and Lifestyle Theories

• Emphasize hereditary vulnerability.
• Focus on the individual, rather than society.
• Lifestyle theories are behaviorally driven (smoking, alcohol, diet).

Determinants of Health

• Population: a group of individuals with shared characteristics.
• Population health: health outcomes of a group, including distribution of outcomes.
• Epidemiology: study of distribution and determinants of disease in populations.

Epidemiology: Distribution

• Descriptive epidemiology focuses on how health outcomes are dispersed across a population.
• Essential for developing hypotheses and planning health services.

Epidemiology: Determinants

• Analytical epidemiology focuses on determinants.
• A determinant influences health in an individual and/or a population.

Key Determinants of Health

• Income and social status
• Employment and working conditions
• Education and literacy
• Childhood experiences
• Physical environments
• Social supports and coping skills
• Healthy behaviors
• Access to health services
• Biology and genetic endowment
• Gender
• Culture
• Race / Racism

Social Determinants of Health

• Pathways by which social conditions affect health that can be altered by informed action.
• Shaped by distribution of money, power, and resources at global, national, and local levels, influenced by policy choices.

Physical Determinants of Health

• Factors in the physical environment which affect health risk and outcomes.
• Air quality and air pollution.
• Water quality and safety.
• Soil contamination.
• Occupational hazards and risks.
• Motor vehicle usage and safety.
• Housing.

Social and Physical Determinants of Health Examples

• Psychosocial: knowledge, attitudes, beliefs about health and illness.
• Biological: inherited disorders.
• Environmental: violence, genocide.
• Health Policy: access to healthcare.
• Individual Behaviours: smoking.

Root, Underlying, and Proximal Determinants of Health

• Root Causes:

  • Natural Environment: climate, water, food supply.
  • Macro Issues: historical conditions, demography, governance, economic and political policies, conflicts, inequalities

• Underlying Causes:

  • Built Environment: land use and city planning, transportation systems, services and facilities.
  • Social Context: community policies and investments, enforcement of ordinances, civic participation, quality of education.

• Proximal Causes:

  • Material Circumstances: income, living and working conditions, food availability, environmental toxins.
  • Behavioural Factors: physical activity, smoking, alcohol use, dietary practices, sexual behavior, use of health care.
  • Psychosocial Factors: education level, social participation and integration (or exclusion), social support, available social networks.

Risk Factors

• Health determinants linked by evidence to specific health outcomes.
  • Intrinsic: non-modifiable, biological (age, sex, genetics).
  • Disease-Related
  • Behavioral: lifestyle choices.
  • Physical Environment
  • Social Environment

Common Risk Factors

• Under or over nutrition
• Other dietary risks (nutrient deficiencies)
• High fasting plasma glucose
• High or low BMI
• Unsafe sex
• Tobacco use
• Alcohol use
• Lack of water and appropriate sanitation
• Exposure to air pollution or other environmental contaminants
• Experiencing situations of trauma or abuse

Health Inequities

• Life Expectancy at Birth: years a newborn is expected to live if current mortality trends continue.
• Neonatal Mortality Rate: infant deaths under 28 days per 1000 live births.
• Infant Mortality Rate: infant deaths under 1 year per 1000 live births.
• Under-5 Mortality Rate: probability of death before age 5 per 1000 live births.
• Maternal Mortality Ratio: women dying from pregnancy/childbirth complications per 100,000 live births.

Health Disparities / Inequalities

• Differences in health linked to social or economic disadvantage.
• Inequities are differences in health arising from social conditions where people are born, grow, live, work, and age.

Health Inequality vs Health Inequity

• Health Inequality: equal shares may not address health differences due to different starting points.
• Health Inequity: fair shares give more to some based on underlying needs.

Applying a Critical Lens to Health Research

• Definition of Health: Consider the author's definition (broad or narrow, cultural understanding).
• Health Data: Note the health indicators used (measurable characteristics).

Methodologies in Health Studies

• Quantitative: vital statistics, surveys, administrative health records.
• Qualitative: interviews, focus groups, community-based participatory studies.

Critical Appraisal of Knowledge and Questions to Ask

• Is the source reputable?
• Has the evidence been evaluated and how?
• How up-to-date is the evidence?
• How were things measured? Methods appropriate and trustworthy?
• Are the findings generalizable?
• Is the knowledge biased?

Environmental Determinants of Health

• Geography: global location, country, region, urban/rural.
• Natural Environment: air, water, soil, trees, green space (biotic and abiotic factors).
• Built Environment: housing, community structures, transportation.
• Food Systems: distribution, food security/insecurity, food deserts.
• Macro-Environmental Factors: political, economic, national factors, governance, climate change, war, natural disasters.

Environmental Health Definitions

• Natural environment is life’s foundational support system.
• Environmental health includes aspects of human health, including quality of life, that are determined by physical, chemical, biological, social, and psychosocial factors in the environment.

Environmental Health Burdens

• Poor sanitation and lack of clean water.
• Air pollution (indoor and outdoor).
• Inadequate housing/shelter.
• Changing land use and climate affecting food production/access, culture, livelihoods.
• Pollution and exposure to toxins.

Magnitude of the Indoor and Outdoor Air Pollutant Problem

• Outdoor Air Pollution: worse in lower income urban communities (environmental & industrial waste).
• Indoor Air Pollution: worse in lower income rural communities (solid biomass fuels).

Major Urban Outdoor Air Pollutants

• Particulate Matter: less than 10 microns blocks nasal/bronchial passages. Less than 2.5 microns penetrates lungs/bloodstream.
• Other Pollutants: ozone, nitrogen oxides, sulfur dioxide, carbon monoxide, ammonia, lead, polycyclic aromatic hydrocarbons, volatile organic compounds.

Indoor Pollutant Sources and Health Risks

• Burning solid fuels indoors:
  • Incomplete combustion: particles, gases, chemicals.
  • Smoke: conjunctivitis, upper respiratory irritation, acute respiratory infections.
  • Carbon monoxide: acute poisoning.
  • Long-term effects: cardiovascular disease, pulmonary disease, cancer, adverse reproductive outcomes.

Health Effects of Indoor Air Pollution

• Issues in Birth: miscarriages, early delivery, low birth weight.
• Child Mortality: responsible for up to 10% of mortality of children under 5 years old
• Issues in Brain Development: harms development of healthy children’s brains

Air Pollution Exposure and Health Inequities

• Urban populations: increased exposure to industrial sites, dumps, electrical generators.
• Rural populations: increased exposure to unventilated homes and smoke-producing cook stoves.
• Refugees/migrants: exposure to wood smoke in tents, lack of housing/heating/healthcare during migration.

Aggravating and Intersecting Factors

• Lack of Access to Healthcare : increased rates of fatal pneumonia and asthma.
• Climate Change: Contributes to greenhouse gases.

Causes and Consequences of Unsafe Water

• Causes:
  • Pollution, contamination, toxic exposure.
  • Inadequate sanitation and waste disposal.
  • Poor hygiene practices.
• Consequences: diarrheal illnesses (gastroenteritis, cholera), vector-borne diseases (malaria, dengue, schistosomiasis).

Access to Safe Water Globally

• 1. billion people do not have access to clean drinking water.
• Latin America and the Caribbean: 49 Million
• Middle East: 38 Million
• Sub-Saharan Africa: 314 Million
• South Asia: 229 Million
• East Asia and the Pacific: 406 Million

Important Global Health Water-Related Infections

• Water-Borne: transmitted through ingestion of water. Ex. Cholera.
• Water-Washed: due to poor hygiene from lack of clean water. Ex. Hepatitis A.
• Water-Based: transmitted through an aquatic intermediate host. Ex. Schistosomiasis or Guinea worm.
• Water-Related Insect Vector: transmitted by insects that depend on water to reproduce. Ex. Mosquitos that transmit malaria or dengue.

Water-Related Infection Example: Schistosomiasis

• Mature flukes sexually reproduce in human host, excreted from host into water source via feces.
• Fertilized eggs develop into larvae; infect snail hosts.
• Asexually reproduced within the snail, becoming a type of motile larvae
• Penetrate the skin and blood vessels of humans in direct contact with water source and causes the build up of fluid in the spaces within a person’s abdomen (Ascites)
• Mature flukes return to blood vessels.

Housing Can Affect Health

• Internal Conditions: biological, chemical, physical hazards, physical design and organization of space.
• Area Characteristics: social benefits, location (proximity to services, hazards, community life).
• Housing Tenure: psychological benefits, financial dimensions.

Housing and Living Spaces Impacts on Health

• Pollutants: Building materials, Mold/Bacteria etc.
• Irritants: Fumes, Solvents, Cigarettes, Gases etc.

Canadian Context and Housing

• Unsheltered Homelessness : homeless shelter, on the street or in parks etc
  • 2.6% of male population
  • 2.3% of female population
• Hidden Homelessness : Individuals who had to temporarily live with family or friends etc
  • 15% of population

Core Housing Need and Housing Tenure

• Lack of Affordability: Tenants pay more than 30% of their income on housing. Lack of Suitability: Tenants are living in overcrowding conditions.
• Lack of Adequacy: Occurs when a tenant’s home lacks a full bathroom or requires significant repair.

Neighbourhoods can be Health Opportunity Structures

• Physical Features: environment shared by all residents (air, water, grocery stores).
• Availability of Healthy Environments: decent housing, non-hazardous work, safe play areas.
• Services Provided: education, transport, health.
• Socio-Cultural Features: political/economic history, norms, values, crimes, support networks.
• Reputation of an Area: impacts investment, self-esteem, who moves in/out.

Disasters and Complex Humanitarian Emergencies

• Natural Disasters: occurrence causing damage, loss of life, health deterioration requiring extraordinary response.
• Complex Humanitarian Emergencies (CHEs): violence/loss of life, displacement, damage to societies/economies, need for large-scale assistance.

Factors Affecting the Management of CHEs

• Population Migration
• Corruption
• Disruption of Supply Chains
• Collapse of State or National Level Institutions
• Breakdown of Law and Order

Climate Change Threatens Health

• Rising temperature.
• More extreme weather.
• Rising sea levels.
• Increasing CO2 levels.

Minimizing Environmental Health Threats

• Outdoor Air Pollution: minimize car usage, use less energy, avoid burning garbage.
• Indoor Air Pollution: indoor stoves with efficient fuels.
• Water Supply and Hygiene: promote hand-washing.
• Sanitation: low-cost sanitation systems.
• Housing: homes suited to the climate, avoid harmful chemicals in materials.
• Climate Change: reduce greenhouse emissions, shift to clean energy, reduce overconsumption.

Social Determinants of Health: Examples

• Social relationships and supports
• Social Norms
• Social Policies
• Societal Features
• Political and Economic systems

Health Advice from a Lifestyle Perspective

• Don’t smoke
• Follow a balanced diet
• Keep physically active
• Manage stress by making time to relax
• Drink alcohol in moderation
• Cover up in the sun
• Cancer screening opportunities
• Be safe on the roads
• Practice safer sex
• Learn the First Aid ABCs (Airway, Breathing, Circulation)

Cultural Influences on Health

• Culture: shared beliefs, ideas, values, and behaviors.
• Forms the basis of a group’s identity, typically sharing a common ideology and cosmology.
• Culture can also be described as ideology linked to behavior

Health Behaviours and Culture

• Nutrition and eating practices
• Gender roles and activities
• Tobacco or alcohol use
• Social and sexual relationships and practices
• Hygiene practices
• Marriage rites
• Funeral practices

Examples of Culture Negatively Impacting Health

• Food Preferences: undercooked meats/fishes, unpasteurized milk.
• Settlement patterns that can increase risk for the spread of infectious disease
• Historical racism that can affect access to services and resources

Examples of Culture Positively Impacting Health

• Vietnamese Stilt Houses: Prop the house above mosquito flight ceiling to protect against malaria
• Sardinian Inverse Transhumance: Cattle grazing patterns that were adaptive to avoid peak mosquito concentrations to mitigate malaria rates
• Social Connectedness

Social Connectedness and Perception of Health

• Those with a strong sense of community are 2.6 times more likely to also report very good or excellent general health, and 3.2 times more likely to report very good or excellent mental health as opposed to those who did not have strong feelings of social connection in their communities

Social Connectedness and Health Behaviours

• Those who reported higher levels of social connectedness also reported healthier lifestyle behaviors like walking more, eating healthier, or engaging in more moderate amounts of screen time

Social Connectedness and Health Improvements

• Declines in health were also associated with low levels in community belonging

Socioeconomic Status (SES)

• An individual’s or group’s position within a hierarchical social structure
• Socioeconomic Position:
  • The social and economic factors that influence what positions individuals or groups hold within the structure of a society

Measuring Socioeconomic Status

• Area-Level Indicators:

  • Proportion of a population with at least a high school education
  • Proportion of a population working in manual labour positions
  • Average family income in a specific census subdivision

• Individual Indicators

  • Level of education attained
  • Annual or family income
  • Their occupation which is closely tied to social “class”

Indicators for Measuring Life Course SES

• Childhood

  • Parental education and occupation
  • Household income
  • Household conditions

• Young Adulthood

  • Education

• Professional Life

  • Occupational social class
  • Unemployment
  • Income
  • Wealth / Deprivation
  • Household conditions
  • Partner’s SES
  • Assets transfer occurring when starting a family

• Retirement

  • Wealth / Deprivation
  • Household conditions
  • Assets transfer across generations occurring at death

Relationship Between SES and Health

• SES: Education, Occupation, Income, Subjective SES, SES Inequality
  • Connecting Pathways: What higher or lower levels of SES allow access to in the material sense , how higher or lower levels of SES affect how people see themselves & their abilities
  • Health Outcomes: Cognitive Functioning, Physical Functioning, Disease, Mortality

SES and Health: When SES Matters the Most

• Critical Period Explanation:Early life influences influence later life outcomes.
• Pathway Explanation: Early experiences can set individuals on different health trajectories
• Cumulative Explanation: Day to day exposures to adversity may build to cause adverse health outcomes over time

Neurobiological Pathways Affected by Low SES

• Childhood and Adulthood SES: SES at younger ages can affect the neuroplasticity of the brain
• Physiological Effects: SES adversely impacts limbic neuroplasticity, and effects allostatic control systems
• A low SES can lead to a large allostatic load on the body and brain and increase one’s risk for poor health

Adverse Childhood Experiences and Adverse Community Environments

• Adverse Childhood Experiences:
  • Experiencing violence, abuse, or neglect
  • Witnessing violence in the home or community
  • Having a family member attempt or die by suicide
• Adverse Community Environments:
  • situations where social supports are not available
  • where safety might not be assured

Income as a Key Social Determinant of Health

• People living in Canada’s highest income urban neighborhoods live an average of three years longer than those in the lowest income neighborhoods
• The poorest 20% of Canada’s population have more than double the chance of having two or more chronic conditions, including heart disease and diabetes, than the richest 20%
• Education as a Key Social Determinant
• Higher levels of educational achievement are associated with improved health outcomes across the globe and have intergenerational effects

Occupation as a Key Social Determinant

• There are gender patterns in may jobs, and gender and occupation influences often act synergistically
• Occupational measures don’t always capture unemployed or retired positions, persons in transient jobs, or students
• Occupational realities may differ between societies and there may be quite a bit of variation within any one occupation

Social Determinants of Health and Health Inequalities

• Life Expectancy:
• On average there is an 18 year difference in life expectancy between people who live in high- versus low-income countries Premature Death:
• The majority of 15 million annual premature deaths due to non-communicable diseases occur in low- and middle-income families
• Disease:Relative gaps within countries between poorer and richer subgroups for diseases like cancer have increased in all regions across the world
• Under-5 Mortality Rate :Under-5 mortality rate is eight times higher on the African continent than the European region

What Causes Health Inequalities

• Levels of Power and Resources: groups have different access to resources, impacting personal control.
• Levels of Exposure to Health Hazards:, some are at greater risk of experiencing or being exposed to factors that can negatively affect their health, such as poor housing or working conditions that are unsafe
• Impacts of Health Hazards: even when everyone is exposed to the same health risks, their health may not be affected in the same way
• Impacts of Being Sick: Illness and chronic disease can have a more serious impact for some groups in society compared with others
• Experiences in Early Childhood :Disadvantage early in a person’s life can accumulate and lead to poor health in adulthood and old age

Health Inequalities and the Social Staircase

• Bottom: Those at the bottom have the lowest chance of dying prematurely or having a serious illness than those on the highest step
• Middle : People on the middle step are still more likely to have a shorter life span and be less healthy compared to those on the top step
• Top: People on the top are generally healthier than everyone else and tend to live longer
• Income Inequality Mechanisms: effectis of income inequality on help exacerbate the underinvestment in social goods and trigger harmful psychosocial effects

Addressing Social Determinants of Health

• Living Conditions: The circumstances in which people are born, grow, live, work, and age
• Policy and Resources: Tackle inequitable distribution of power, money, and resources particularly through economic policies and better governance
• Problem Solving and Action: Measure and understand the problem and assess the impact of action
• Develop a workforce that is trained in understanding Social Determinants of Health and Disease
• Raise public awareness about Social Determinants of Health and Disease