Lecture 5; Introduction To Case-Control Study Disease Flashcards
what does an analytical epidemiology involve?
Comparing two groups of people
Ie nurse being slim and obese/ rubber workers vs general population
What are the 3 types of observational studies?
Cross-sectional surveyors
(Analytical studies;) cohort studies and case-control studies
What is an example of experimental studies?
random control trails (RCTs)
What are the two types of epidemiological study designs?
Observational and experimental studies
What is the difference between a cross-sectional survey and a case-control study?
You find cases (prevalence) in a CS survey and that’s it
In a CC study you find cases and controls and compare and contrast case and control groups on potential casual factors
What are the issues for case-control studies?
- selection bias
- information bias
- confounding
What is selection bias and how do you deal with it?
.
What is information bias?
Non-differentiated misclassification ie randomly inaccurate measurement
Systemic (differentiate) misclassifiction ie (comparing a orange and a banana) recall bias, assessor bias (Dont use a registra to look at one group and a medical student to look at the other group), data collection methods differ (treat all participants in the groups the same)
What is a confounder?
A confounder is an unobserved exposure associated with the exposure of interest and is a potential cause of the outcome of interest. Confounders lead to bias that distorts the magnitude of the relationship between two factors of interest.
How can confounding be sorted?
It can be minimised in selection
It can be adjusted for in analysis
.
What is a null hypothesis?
(in a statistical test) the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.
What rates can you calculate in a case control study and why?
Only an odds ratio
Because there is no element of time
