Public Health Flashcards
(198 cards)
Define primary prevention?
Preventing a disease from occurring in the first place.
What are some examples of primary prevention?
Change4life,
5-a-day,
Vaccines
Define secondary prevention?
Detecting a disease in its early or pre-clinical phase to alter its course + improve health outcomes
What are some examples of secondary prevention?
All screening programmes (breast, bowel, cervical cancer, heel prick)
Define tertiary prevention?
Attempting to slow down disease progression + prevent complications of a disease, helping people manage their illness effectively.
What are some examples of tertiary prevention?
Diabetic foot care,
Attending rehab after a stroke to prevent immobility.
What is the population approach to prevention?
Preventative measure delivered on a population wide basis
Seeks to shift the risk factor distribution curve
What are some examples to the population approach to prevention?
Dietary salt reduction through legislation to reduce BP
Adding iodine to salt to prevent iodine deficiency
What is the high risk approach to prevention?
Identifying individuals above a chosen cut-off + treating them
What are some examples of the high risk approach to prevention?
Screening for HTN + treating them.
What is the prevention paradox?
A preventative measure which brings much benefit to the population often offers little to each participating individual.
it’s about screening a large number of people to help a small number of people.
Define screening?
A process which identifies seemingly well individuals who may be at risk of a disease, in the hope of catching the disease at its early stage
What is screening not?
It’s not a diagnostic process, simply a means of assessing risk + catching diseases in their early stage.
Define sensitivity?
Sensitivity = the proportion of people with the disease who are correctly identified by the screening test
A / A + C
Define specificity?
The proportion of people without the disease who are correctly excluded by the screening test
D / D + B
Define positive predictive value?
The proportion with a positive test result who actually have the disease. Dependent on underlying prevalence
A / A + B
Define negative predictive value?
The proportion with a negative test result who do not have the disease. This is lower if the prevalence is higher
D / D + C
What are some examples of population-based screening programmes?
Cervical and breast cancer
What are some examples of opportunistic screening programmes?
BP measurements in GP surgeries
What are some other types of screening?
Screening for communicable disease.
Pre-employment + occupational medicals.
Commercially provided screening (pay company to send off blood + get tested for a variety of different genetic issues).
Genetic counselling (genetic testing for people with FHx of diseases).
What are some disadvantages of screening programmes?
Exposure of well individuals to distressing or harmful diagnostic tests.
Detection + treatment of sub-clinical disease that may have never caused any problems.
Preventative interventions that may cause harm to the individual or population.
What are the Wilson + Junger criteria for screening?
The condition should be an important health problem.
There should be an accepted treatment available to pts.
Facilities for diagnosis + treatment should be available.
There should be a recognisable latent or early symptomatic stage.
There should be a suitable test or examination.
The test should be acceptable to the population.
The natural history of the condition should be understood.
There should be a policy on whom to treat as patients.
The costs of the screening should be economically balanced.
Screening should be a continuous process, not just a one off.
Define lead time bias?
When screening identifies an outcome earlier than it would otherwise have been identified + results in an apparent increase in survival time, even if screening has no effect on the outcome
What is length time bias?
A type of bias resulting from differences in the length of time taken for a condition to progress to severe effects that may affect the apparent efficacy of a screening method.