Overview of epidemiology: concepts & study design Flashcards
What are the top 3 study designs in the hierarchy of evidence starting from the top?
Systematic reviews / meta-analysis
Randomised controlled trials
Non-randomised controlled trials
Which category of study would be used to determine whether a new intervention works?
Experimental studies (RCTs + Non RCTs)
What are the 2 types of experimental studies?
Randomised controlled trials
Non-randomised controlled trial
What category of study would be used to determine whether an exposure and outcome are associated with each other?
Analytical observational studies
What are the 4 types of analytical observational studies?
Cohort
Case-control
Cross-sectional studies
Ecological studies
What category of study would be used to determine the pattern of disease in a population?
Descriptive observational studies
What are the 3 types of descriptive observational studies?
Cross-sectional studies
Ecological studies
Case reports and case series
What are the 4 reasons for finding a specific result in study?
Truth
Chance
Bias
Confounding factor
In epidemiology, what is bias?
A systematic error in the design or conduct of a study that results in giving a result different from the truth
What are the 2 main types of bias?
Selection bias
Information bias
What are the 4 types of selection bias.
Self-selection (volunteer) bias
Non-response bias
Healthy worker effect
Survival bias
What are the 4 types of information bias.
Recall bias
Interviewer bias
Social desirability bias
Attrition bias
What is a confounder?
A factor associated with both an exposure and an outcome that influences the association
A study finds a link between alcohol consumption and lung cancer. Name a potential confounding factor.
Smoking
Name and briefly describe the 3 association features of the Bradford Hill criteria.
Strength of association: larger effect sizes more likely to be causal
Specificity: an outcome has one cause, or vice versa
Consistence: replicable findings in different subgroups
Name and briefly describe the 3 remaining features of the Bradford Hill criteria.
Biological plausibility: demonstrable pathological mechanism
Analogy: similar known associations e.g. virus + birth defects
Coherence: observed association conforms with current knowledge
Name and briefly describe the 3 exposure-outcome features of the Bradford Hill criteria.
Temporal relationship: exposure occurs before outcome
Dose-response relationship: if more exposure increases risk of outcome, more likely to be causal
Reversibility: removing exposure reduces the risk
