Preventative Medicine Flashcards
What is distribution?
A description of frequency, counts, rates or risks
What do descriptive studies do?
Describe cases
Describe populations
What is the purpose of descriptive studies?
To know how much disease a region or group has
What are the pros of an anecdote and case series?
Quick
Easy to perform in clinic
Provides new, previously unobserved conditions
Provides new potential risk factors
What are the cons of an anecdote and case series?
Not scientific and unable to test a hypothesis
Seriously affected by observer bias
Difficult to make inference about disease cause
What does a cross sectional survey observe?
A snapshot of people with an outcome
What are the pros of a cross sectional survey?
Quick
Good at estimating prevalence or burden
What are the cons of a cross sectional survey?
One represents that point in time
Cannot estimate incidence
Sampling frame may lead to bias
What does the counterfactual method ask?
If the disease would have happened at the same time in the same person and if the factor was not present
What are the pros of ecological studies?
Less expensive Less prone to bias Easy to perform Provides new hypothesis about the causes of a disease or condition Provides new potential risk factors
What are the cons of ecological studies?
Ecological fallacy
Assume that the averages apply to all individuals
These types of studies are retrospective and happen after the disease has been diagnosed
Case control study
What does it mean if the odds ratio is 1
No effect
What does it mean if the odds ratio is >1
There is an association
The exposure raises the risk of disease
What does it mean when the odds ratio is
There is an association
The exposure lowers the risk of disease
What are the pros of case control studies?
Good for rare disease and rare exposures
Quick
What are the cons of case control studies?
Prone to selection bias
Especially prone to participation bias
Finding a suitable control group can be difficult
Difference to recall leads to bias
Which is the best observational study?
Cohort study
What are the requirements for candidates of a population study?
Must be at risk for the outcome
Free of the outcome at the start
What are the pros of cohort studies?
Good for rare exposures
Can look at multiple outcomes
Reduces information bias
Direct measurement of incidence
What are the cons of cohort studies?
Inefficient for rare diseases
Expensive
Loss of follow up
What is a randomised controlled trial also known as?
A clinical trial
What does a randomised controlled trial test?
How well an intervention works
What are the pros of randomised controlled trials?
Strongest evidence for causality
No selection bias
Less observer bias
What are the cons of randomised controlled trials?
Not real life
High cost
Inappropriate/unethical for many research questions
What is error?
The difference between an estimated/measured value and true value
What are some sources of error?
Study design Data collection Data management Sample collection Lab analysis
What is bias?
Systematic non random deviation of result and interferences from the truth or processes leading to such a deviation
What is diagnostic bias?
When diagnosis is made based on exposure
What is self selection bias?
When subjects make decisions
What are the different types of information bias?
Recall
Interviewer
Surrogate
What are the three categories of prevention?
Primary
Secondary
Tertiary
What is the aim of primary prevention?
Prevent the onset of disease
What is the aim of secondary prevention?
Halt the progression once started
What is the aim of tertiary prevention?
Limit disability and complications established in disease
What is Rose’s Population Theory?
an approach to preventive medicine and public health which predicts that shifting the population distribution of a risk factor prevents more burden of disease than targeting people at high risk
Ie shift the mean to the left
What does the population mean predict?
The prevalence of cases
What is the prevention paradox?
The majority of cases of a disease come from a population at low or moderate risk of that disease, and only a minority of cases come from the high risk population (of the same disease). This is because the number of people at high risk is small.
