Understanding Disease Prevention

Prevention Overview

• Prevention involves measures to avoid or reduce the number and severity of diseases and accidents.

Individual Prevention

• Aims to change individual behaviours, including things like mandatory vaccinations, smoking bans, recommended screenings, and health education.

Collective Prevention

• Focuses on modifying general environmental conditions to diminish risk factors, like ensuring water and air safety.

Preventative Medicine

• Consists of studying and implementing medico-sanitary resources to prevent illness, avoid their development, and reduce or eliminate resulting issues.

Differences between Clinical and Public Health Approaches

Natural History of disease and intervention

• Primary prevention occurs prior to risk factors
• secondary occurs during biological onset or at symptoms
• Tertiary occurs after diagnosis and during therapy

Determinants of Health

• Health is determined by factors tied to individuals, the environment and socioeconomic conditions.

Levels of prevention

• Primary Prevention aims to avoid the appearance of new cases of diseases.
  • Includes actions intended to diminish the incidence of a disease according to the WHO (World Health Organization)

Actions in primary prevention

• Health Promotion
• Health Education
• Vaccination

Health Promotion

• Involves "giving people the means to have more control over their own health and to improve it." (Ottawa Charter, 1986)
• It includes focusing on strengthening people’s abilities, modifying social, environmental, political, and economic conditions to reduce health impact.

Role for health promotion

• It's "a resource for everyday life which highlights social and individual resources, and physical capabilities, to pursue ambitions, meet needs, and evolve with or adapt to one's environment." (Ottawa Charter, 1986)
• Everyone is responsible: parents, teachers, associations, elected officials, business leaders, administration officials, trade unionists, doctors, etc.
• The means is to act on the various factors influencing the health condition of populations.

Characteristics of Health Promotion

• The approach is ecological, politically oriented, and attentive to environmental aspects than purely focused health education.
• Participatory, empowering communities with autonomy for better control over life and health.
• Also involves action on the determinants of health and utilizing multiple, complementary strategies.

Intervention Strategies in Health Promotion: There are 5 listed

• Creating supportive environments
• Building healthy public policies
• Improving personal abilities through education
• Providing access to necessary information to reinforce community action
• Re-orientating health services.

Create Supportive Environments

• It involves an environment that exerts a positive influence on an individual's health and it facilitates beneficial choices.

Developing Healthy Public Policies

• It enhances social, economic, and environmental condition for human and working environment and is developed by the government and institutions.
• Methods include legislation, fiscal (tax) measures, and organizational changes.

Empowering individuals through education

• It involves providing information and health education.
• It enables greater control over health and promotes favorable health choices.
• It can be applied in schools, homes, and works.

Reinforce Community Action

• Concretely involves the community´s participation in prioritizing, decision making, and planning strategies to reach better health.

Redirecting Health Services

• it involves changing attitudes and the internal health structures
• Managing indiviudal/ communal health that is beyond focusing on illness
• Balancing care and prevention.

Secondary Prevention and screening

• Intends to prevent development of an illness in the subject
• Consists of the following:
  • Early detection
  • Early treatments

Definition of "Screening"

• A general definition of "screenining" is to systematically research and discover what is less clear.
• A medical definition is to identify subjects that display either:
  • An apparent illness
  • A risk of a provided illness

WHO Definition

• According to WHO, screening constitutes to identifying, predictably with the aid of applied tests and standard forms, those that have illness but are not known

Different type of screening

• Systematic screening: A volunteer group is selected for the testing

Screening that is selective or targeted

• The volunteer group is selected based of criteria's

Comunnity screening

• The volunteer group is selected based on community based work and usually relies on campaigns with a first come first serve method

Oppurtunistic Screening

• Volunteer patients are taken from hospitals

Multiple Screening

• Volunteer patients are tested at one for other illnesses

Diagnostic vs Screening

Why do Screening

• Favorable fallout on patients

Benefits of Screening

• Improves survivability and is cost effective
• Improves overall health or reduces mortality rate

Planning Screening Program

• Planning screening needs:
  • Which illness to look at
  • Which best should be utilized

What illness to look for

• Needs to be extremely serious

Needs to be:

• Of a known existence
• Has an easily identifiable latency stage
• Has a procedure

Qualities for a Test

• Affordable and accessible
• Easy to manage
• Capable and efficient

Test Selection

• Testing should be affordable and easy to administrate

What is False- True- Positive and Negatives

• In the perfect word screen testing would always be true
• This test helps eliminate those the have symptoms

Tests Are Not Always Correct

Lung cancer example:

• An Xray suggests cancer, but the biopsy is not active: False Positives
• Xray shows no sign of cancer, but the biopsy show activity: False Negatives

Test: Intrinsic values

• Tests require an specific ability to differentiate a known active and inactive test subject
• This ability relies on a performance test using intrinsic and extrinsic properties

Defining tests

• We need to first construct a test contingency to calculate which tests to use:

Test that have Sensitivities

• What the chances are what the test shows active disease

Has Specific values

• Probabilities of the patient not getting sick

Calculating with the tables

Defining Tests need reference

• The state can only be confirmed via testing from a specialized

What to look for in a test

• Test and test need to show the expression

Distribution chart

• Red line showing those with sickness and a green line for those who have no sickness

Distribution graph is split

• The lines are divided so those with negatives results fall on the left and positive on the right

It might be preferable to have tests that display:

• Low positive negative results or high false positive rate given circumstance

High Negative Results

• A disease that is sever and is highly lethal and can be treated

The Importance of the Disease:

• High contact infections would make negatives important

Low positive tests:

• Not cost effective and the disease is easily maintained or has low lethality

Final Validity

• Can be calculated through this method:
  • People shown to have it divided by the Total Tests Positive

Value Calculation

• The formula value helps determine if value is beneficial
• It requires:
  • **Sensibility
  • **Specificity

If samples are of the population then:

• Test+ divided by All positive test subjects*

Factors of mass testing programs based of studies

• Requires: Importance within Public Health
• Needs a known: Latency Stage
• There is some form of: Treatment

There is influence that can have a favorable change

- There is a test that provide performance and stage

• This technique of testing and screening can be done continuously or when needed
• Needs the backing of the population to properly be a test

Tertiary prevention

• reduces functional and consequential incapacities
• According to the WHO it improves quality of living

Examples (Prevention)