L14 Deciding on the interventions to improve population health Flashcards
What is the purpose of population health?
Provide the maximum benefit for the largest number of people, at the same time reducing inequities in the distribution of health and well-being
What study could be used to define the problem?
Cross-sectional studies
e.g. survey asking BMI to determine obesity levels in the population
What study is suitable to identify risk and protective factors?
Cohort (observational studies)
e.g. what effect does high fat diet have on BMI over time?
What study is suitable in order to develop and test prevention strategies?
Randomised controlled trial
Diagnostic tests
Does epidemiology determine the cause of a disease in an individual?
No - determines the relationship between an exposure and outcome in populations
Can preventative measures function before the cause or determinant of a dis-ease is identified?
Yes - e.g James Lind’s experiment
What is James Lind’s experiment?
An early form of a controlled trial in which sailors were given a set diet including citric acid fruit in order to test for the cause of Scurvy
The idea that citric acid fruit should be included in the diet was found before people knew Scurvy was caused by a vitamin C deficiency
What is the Bradford Hill framework?
A guide that aids in determining whether a relationship between an exposure and outcome is causal or not
What are the components of the Bradford Hill Framework?
Temporality Strength of association Consistency of association Biological gradient Biological plausibility of association Specificity of association Reversibility
What is temporality in the Bradford Hill framework?
The exposure must come before the outcome
What is strength of association in the Bradford Hill framework?
By comparing relative risk values between exposure and comparison groups -> a greater relative risk value shows stronger association hence a causal relationship is more likely
What is consistency of association in the Bradford Hill framework?
Replication of the results by different investigators, at different times, by different methods in different places should show similar results
What is biological gradient (dose-response) in the Bradford Hill framework?
Increase in the magnitude of the exposure should be reflected in the the increase of the magnitude of the outcome
What is biological plausibility of association in the Bradford Hill framework?
Association should make biological sense - > explained by science
What is specificity of association in the Bradford Hill framework?
The idea that a single cause should lead to a single outcome -> not relevant as dis-ease occurrences are often due to multiple exposures
What is reversibility in the Bradford Hill Framework?
Changing the exposure in a study should change the outcome
What is a cause of a disease?
An event, condition, characteristic or combination of these factors which play an essential role in producing the disease
What is the causal pie?
A visual representation of the existence of multiple causes to a disease
What are the three types of causes?
Sufficient cause
Component cause
Necessary cause
What is sufficient cause?
The whole pie - the minimum set of conditions without any one of which the disease would not occur
Represents that multiple causes contribute to the occurrence of a disease
Probability of disease = 1
What is a component cause?
Each factor or slice of the causal pie - a factor that contributes towards the disease but is not sufficient to cause dis-ease on its own
Probability of disease when present = 0 - 1
What is a necessary cause?
A slice of the causal pie - a factor which when not present will not lead to the causation of the disease
Probability of disease when present is not 0
What is the general definition of causation
The presence or absence of the cause makes a difference in the outcome
