Health, Disease, Prevention, Primary Health Care and Health Systems

Connect the major public-health concepts from determinants of disease to prevention, Primary Health Care and the functioning of the health system for rapid revision.

1. THE TOPIC IN ONE CONNECTED FLOW

Community Medicine connects the factors that shape health with the way disease develops and the points where prevention can act. Primary Health Care then brings essential services close to communities, while the wider health system provides resources, referral, information and governance needed to support these services.

Health Determinants

Biological, environmental, behavioural, socioeconomic and health-service factors

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Disease Causation

Agent–host–environment interaction or multiple interconnected causes

→

Natural History

Susceptibility → subclinical disease → clinical disease → outcome

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Prevention & Control

Act before risk, before disease, during early disease or after disability

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Primary Health Care

Accessible essential promotive, preventive, curative and rehabilitative care

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District Health System

First-contact care → referral → higher-level services → follow-up

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WHO Health System

Services, workforce, information, medicines, financing and governance

2. KEY CLINICAL CONNECTIONS

Hidden Disease Burden

Few diagnosed cases → larger number of subclinical or undiagnosed cases → iceberg phenomenon → routine clinical data may underestimate community disease burden.

Disease Stage Determines Prevention

Risk factors not yet established → primordial prevention; disease not yet started → primary prevention; early disease → secondary prevention; established disability → tertiary prevention.

From Community Need to Effective PHC

Local health need → community participation + equity + intersectoral coordination + appropriate technology → accessible essential services → improved coverage and outcomes.

Health-System Function

Primary-level care → referral when capacity is exceeded → district or higher-level care → follow-up back in the community → continuity of care.

3. AIM HIGH-YIELD INTEGRATION REVIEW

⭐ Agent + host + environment interact in the epidemiological triad, while complex chronic problems are better understood through multifactorial causation and the web of causation.

Subclinical disease follows biological onset but precedes symptoms → disease may already be detectable before clinical presentation.

⭐ The iceberg phenomenon connects visible diagnosed disease with a hidden burden of mild, subclinical or undiagnosed cases → clinical records alone may underestimate disease prevalence.

Primordial → primary → secondary → tertiary prevention progressively act from preventing risk-factor development to preventing disease, detecting it early and limiting disability.

⭐ Effective Primary Health Care depends on equity, community participation, intersectoral coordination and appropriate technology → essential services become more accessible and relevant to community needs.

Comprehensive PHC addresses broad health needs and determinants, whereas selective PHC concentrates limited resources on selected high-priority interventions.

Health for All aimed for a level of health permitting socially and economically productive life → it did not mean elimination of every disease by the year 2000.

⭐ The six WHO building blocks are interconnected: service delivery + workforce + information + medicines/technologies + financing + leadership/governance → weakness in one can reduce overall health-system performance.

AIM Exam Trap:
Do not confuse comprehensive PHC with simply providing more services. Its defining feature is a broad, integrated approach to health needs and determinants; selective PHC deliberately focuses on a limited set of priority interventions.

Health, Disease, Prevention, Primary Health Care and Health Systems

1. THE TOPIC IN ONE CONNECTED FLOW

2. KEY CLINICAL CONNECTIONS

3. AIM HIGH-YIELD INTEGRATION REVIEW

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