Epidemiology Flashcards
Case Control studies
An observational study
To study the association between risk factors and certain exposures.
“Patient have the disease vs. Controls without the disease” the researcher will retrospectively examine the exposures.
Potential: Recall bias.
Suitable for rare diseases with long latency periods.
Case-Cross over studies
Cases serve as their own controls.
- To evaluate transient exposure as compared to fixed exposure (case-control)
i. e. Immediate Determinants of MI onset: physical, psych and chemical triggers.
Cohort Studies
- Classify subjects based on their exposure status, then followed over a period of time to determine who develops the “disease aka desired outcome”.
- can be retrospective or prospective.
- Calculate RR or incidence.
This type of study is subjected to very low recall bias, and multiple outcomes can be studied simultaneously.
more prone to selection bias
Cross-Sectional Studies
observational in nature and give a snapshot of the characteristics of study subjects in a single point of time.
do not have a follow-up period and therefore are relatively simple to conduct.
As the exposure status/outcome of interest information is collected in a single moment in time, it cannot provide a cause-effect relationship and is the weakest of the observational designs.
This study design is generally used to assess the prevalence of a disease in a population
Ecological Studies
used when data at an individual level is unavailable, or large-scale comparisons are needed to study the population-level effect of exposures on a disease condition.
subject to a type of confounding called an ecological fallacy, which occurs when relationships identified at group level data are assumed to be true for individuals.
Randomized Clinical Trials: Experimental study
The gold standard of study design.
the researcher randomly assigns the subjects to a control group and an experimental group.
Randomization avoids confounding and minimizes selection bias.
