Module 1 - Unit One - Introduction to Concept of Health and Disease

Main ideas & lessons (concepts of health and disease)

1) How “health” and “disease” have been understood over time

• The meaning of health and the cause of disease has evolved across centuries, influenced by:
  • Societal perspectives
  • Professional/medical perspectives
• Earlier, health was often framed as practical life wisdom (e.g., “health is wealth”), linked to productivity and performance.
• Modern global thinking increasingly frames health as a developmental and well-being issue, reflected in the Sustainable Development Goals (SDGs) (e.g., health and well-being).

2) Central role in medicine and public health

• Different medical systems and public-health approaches depend on how health is defined:
  • Allopathic (Western)
  • Homeopathy
  • Ayurveda
  • Siddha
  • Unani (and related indigenous systems mentioned)
• Interventions and services offered to the public vary depending on the underlying health concept.

3) WHO core definition of health and disease

• Health (WHO): complete physical, mental, and social well-being
  • Not merely absence of disease or infirmity.
• Disease (WHO concept): an abnormal condition affecting body functions.
• Key implication: health is well-being, not only “no illness.”

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Four major conceptual understandings of health (with features)

A) Biomedical (disease-focused) concept

• Core idea: Health = absence of disease/infirmity
• Roots: Western medicine / alopathy
• Key features
  • Body is viewed as a machine
  • It should be repaired when malfunctioning
  • Focus on pathogens (bacteria, viruses, parasites)
  • Diagnosis identifies the pathological agent
    • using blood tests, X-rays, and other investigations
  • Treatment involves:
    • medical technology
    • pharmaceuticals
  • Doctors/specialists are primary decision-makers
• Strengths
  • Advanced diagnostics
  • Rapid tests and precise options
  • Evidence-based interventions (e.g., vaccine efficacy, clinical trials)
  • Effective for acute/emergency and infectious diseases
    • Example mentioned: advanced radiotherapy for cancer
• Limitations
  • Ignores mental, social, and emotional factors
  • May treat symptoms rather than underlying causes
  • Can promote a passive patient role
• Public health application noted
  • Essential for controlling epidemics/pandemics and acute case management
  • Often used alongside other comprehensive care models

B) Ecological (environment-human balance) concept

• Core idea: Health results from a dynamic equilibrium between humans and their environment
• Key features
  • Includes biological, physical, and social environment
  • Considers environmental impacts such as:
    • climate
    • pollution
    • biodiversity loss
    • urbanization
• Emphasis
  • Interconnectedness between health and environment
  • Ecosystem health affects human well-being
  • Prioritizes prevention and sustainability
• Strengths
  • Promotes preventive and sustainable health strategies
  • Informs policy for environmental protection and urban planning
• Examples of how it affects health outcomes
  • Air and water pollution → respiratory and waterborne diseases (e.g., diarrhea, typhoid, polio)
  • Deforestation and land-use change → vector-borne disease risk
  • Climate extremes → health risks (heat strokes, malnutrition, changing vector patterns)
• How to apply ecologically (public health programs)
  • Environmental health programs
  • Sanitation and clean air
  • Urban planning for:
    • green spaces
    • walking spaces
  • Climate adaptation and health policies
  • One Health approach (human–animal–environment linkage)
• One Health / program examples mentioned
  • “Clean environment = better health” (Swachh Bharat mission referenced as example)
  • National programs for climate change and human health linkage
  • Vector-borne disease control
  • WHO health-environment linkage initiatives
  • UNICEF WASH (Water, Sanitation and Hygiene)
  • Climate-sensitive disease surveillance systems

C) Psychosocial concept

• Core idea: Health includes mental and social well-being, not just biology
• Key features
  • Integrates psychological, social, and biological aspects
  • Goes beyond absence of disease:
    • focuses on mental/emotional/social well-being
• Key components mentioned
  • Stress
  • anxiety
  • emotions
  • coping skills
• Why it matters (examples and claims)
  • During COVID-19: stress, loneliness, emotional instability
  • Bipolar disorder/anxiety/depression described as leading causes of disability (as stated)
  • Loneliness linked to:
    • weaker family bonds
    • reduced social support
    • increased mental stress and anxiety
• How psychosocial health is applied in public health
  • National mental health policy/program examples mentioned
  • Integration of mental health into primary healthcare
  • District-level mental health programs
  • Awareness, early detection, and referral services
  • Use of measurement scales to identify stress/anxiety/depression
• Mechanism emphasized
  • Stress affects physical health and immune function
  • Can contribute to psychosomatic disorders and mental health problems

D) Holistic concept (whole-person, multi-domain well-being)

• Core idea: Health is comprehensive, combining:
  • physical
  • mental
  • social
  • emotional
  • spiritual well-being (not limited to religion; includes meaning/purpose/values)
  • plus environmental harmony (included as a component)
• Key components of holistic health (stated as five)
  • Physical
  • Mental
  • Social
  • Spiritual
  • Environmental
• Underlying principles
  • Treat the person, not just the disease (or only “diabetes”)
  • Consider:
    • what the person eats
    • where they live
    • how they live
    • emotional stability/stress levels
  • Focus on:
    • prevention
    • health promotion
  • Healing involves:
    • self-care
    • empowerment
    • interconnectedness across life domains
• How holistic health is applied in public health
  • Community programs that encourage:
    • community participation
    • empowerment
  • Focus on lifestyle and self-care, including:
    • traditional practices
• Holistic practice examples mentioned
  • Ayurveda balance (dosha concepts referenced)
  • Integration of traditional systems into primary healthcare:
    • Ayurveda, Unani, Siddha, Homeopathy (as stated)
  • Use of yoga and naturopathy
  • Traditional healing/wellness education in:
    • schools
    • workplaces
• Noted trend
  • Even some allopathic practice includes holistic elements:
    • dietician guidance
    • yoga/lifestyle advice
    • counseling for chronic disease management

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Theories of disease (how causes were explained historically and scientifically)

1) Supernatural/religious/spiritual theories

• Illness may be attributed to:
  • sin or moral/spiritual causes
  • punishment in past lives (as described)
  • witchcraft or magic
  • prevailing religious/spiritual beliefs influencing interpretation of disease

2) Hypocratic theory (humor imbalance; pre-scientific framework)

• Disease results from imbalance of four humors
  • mentioned humors: blood, yellow bile, black bile, and another humor (blue/bile mentioned in subtitles)
• Health occurs when humors are in balance

3) Ayurvedic theory (dosha imbalance)

• Tridosha theory (pitta, vata, kapha referenced)
• Health from balance; disease from imbalance

4) Germ theory / agent theory (microorganisms)

• With advances like the microscope, diseases were linked to microorganisms
  • called bacteria/viruses
• “Agent theory” aligns with biomedical thinking:
  • microorganisms as the cause

5) Epidemiological triad (agent–host–environment)

• Disease depends on interaction among:
  • agent
  • host
  • environment
• Explains why not everyone exposed becomes ill
  • Example concept: tuberculosis transmission depends on crowding, exposure, and environment

6) Multicausal / multifactorial theory (non-communicable diseases)

• For diseases like cancer, diabetes, hypertension, cardiovascular diseases:
  • no single agent is responsible
  • multiple contributors are involved:
    • sedentary lifestyle, obesity, stress, smoking, alcohol, etc.

7) Web of causation

• Multiple factors interact in chained relationships
• Example chain given in subtitles:
  • sedentary life → obesity → joint pain → stress → more eating → further obesity

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Health definition critique and key properties of health

Critique of WHO definition

• WHO’s definition is described as an ideal goal
• It may be unrealistic for anyone to be fully “complete” physical/mental/social well-being at all times.

Features emphasized in the lecture

• Dynamic concept: health changes over time (not stagnant)
• Subjective: people may rate health differently
  • even individuals with disabilities may consider themselves healthy based on coping, contentment, or lack of additional disease
• Continuum model: health and disease are not binary
  • a spectrum from optimal wellness to severe illness
• Health can improve or worsen with:
  • lifestyle choices
  • environment
  • genetics
  • age-related changes

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Dimensions and determinants of health

Health dimensions (mentioned)

• Physical
• Intellectual
• Emotional
• Social
• Spiritual values/faith also included (as part of holistic view)
• Example used: social deviance can mean “socially unhealthy” even if physically healthy

Social determinants of health

• Health is influenced by broader structures including:
  • political system
  • economic conditions and job security
  • access to education
  • access to healthcare services
  • neighborhood and built environment
  • overall social protection and community conditions
• Emphasis: health is shaped not only by biology or microorganisms but by social conditions.

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Modern health promotion and global health shifts

Health as a resource for everyday life

• Health promotion described as:
  • enabling people to increase control over and improve their health
• Includes physical and psychological and social factors
• Mentions the Ottawa Charter concept as a foundation (implied)
• Health promotion scope:
  • social determinants, well-being, equity
• Technologies and services may not be accessible to all → equity concerns

Epidemiological shift in global disease patterns

• Shift noted from:
  • dominance of communicable/infectious diseases
  • toward increased non-communicable diseases (NCDs) and nutritional problems
• Infectious diseases still persist via:
  • pandemics and emerging diseases
• Mental health highlighted:
  • anxiety/depression described as top global disability causes
  • stigma can prevent early care

Role of technology with equity concerns

• Mentioned advances:
  • AI, genomics, diagnostics (e.g., MRI/real-time monitoring)
  • telemedicine for remote access
  • variable tracking of glucose and BP patterns
• Limitation:
  • not everyone can afford or access advanced tools
• Need balance between:
  • technological advancement
  • cultural beliefs and health-seeking behavior
  • societal stigma (mental illness, HIV mentioned)

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Public health policy actions mentioned (examples of population-level prevention)

• Vaccination programs
• Sanitation and clean water
• Tobacco laws
• Road safety rules
• Food regulation and food safety
• General theme: population-level impact is greater than individual-only care.

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Universal health coverage and “five key functions” (as stated)

• Mentioned goal: Universal Health Coverage (UHC) (as a WH/WHO-driven goal)
  • ensures access regardless of:
    • gender
    • economic status
    • vulnerable/underserved status
• Five key functions mentioned for promotion and prevention:
  • Policies
  • Environmental policies
  • Community action
  • Skills
  • Services (Context: to promote health “before you become sick.”)

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Drivers of change and future directions

Key drivers

• Medical advances and technology
• Social determinants of health
• Urbanization and globalization
• Climate change impacts
• Increased awareness of:
  • mental health
  • NCDs

Future directions mentioned

• Genomics
• Artificial intelligence
• Climate-resilient health systems
• One Health (again emphasized)
• Focus shifting toward wellness, not just treating disease.

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Overall “new philosophy” / concluding themes

• Health is:
  • fundamental human right
  • essential for productive life
  • central to quality of life
  • inter-sectoral (requires coordination across sectors)
  • a major social investment
• Goal: “health for all,” including physical, mental, social, and spiritual well-being.

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Speakers / sources featured (as named in subtitles)

• WHO (World Health Organization): health and disease definitions; health promotion and UHC references; health-environment linkage initiatives mentioned.
• Hippocrates: four-humor concept (humoral imbalance).
• Ayurveda / Ayurvedic tradition: Tridosha concept (pitta, vata, kapha) (mentioned as Indian cultural theory).
• UNICEF: WASH (Water, Sanitation and Hygiene).
• Government of India: “Swachh Bharat mission” referenced; national programs referenced.
• Ottawa Charter for Health Promotion: referenced as the foundation for modern health promotion (conference context).
• ATo/“First international conference on health promotion” (Ottawa, Canada): referenced.
• WHO/Global burden of disease (GBD): referenced in relation to disability causes (bipolar/anxiety/depression described in subtitles).
• UN organizations / missions mentioned: UNICEF and WHO explicitly named; other government bodies referenced generally (no additional named institutions).