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PUBLIC HEALTH:CASE CONTROL STUDIES - Coggle Diagram
PUBLIC HEALTH:CASE CONTROL STUDIES
Define
Cases>people with disease of interest
Controls>People free of disease
Analytic
Strengths
suited for study
Assess multiple risk factors for 1 disease
quick and inexpensive
efficient=rare diseases
Limitations
Prone>bias
inefficient for rare disease studying
Difficult to establish temp. relationship
KEY FEATURES
Collection of info for both cases & controls
Calculates>Measure of association
Participants>selected according to disease status
CONSIDERATIONS
Selection of CONTROLS
Ensure proper selection>reduce bias
Sources:Hosp,clininc,neighbourhood
Independent of exposure
Determining Exposure
Misclassification>bias
Exposure collected via F2F interview,questionnaires(postal),telephone
Use memory aids>increase recall of exposure
Blind the cases & controls to disease status>to get exposure info in standard way
Same methods used
Selection of CASES
Incident cases prefered , same source(hosp.,
Same source(Hosp, clinics , nested cohort)
standard definition(Xrays,lab findings)>ensure validity
Measuring Of Association
Odds of exposure among cases / odds of exposure among controls
Odds Ratio (OR)
Interpretation:
OR >1 :exposure is likely to be a risk factor
OR < 1: Exposure is likely to be a protective factor
OR = 1:cases exposure=controls exposure
Precision:Confidence intervals
helps interpretation due to uncertainty that results from random variation due to sampling