6. Observational Study Designs: Cohort Studies Flashcards
Under the algorithm for determining study type - what type of study is it when an investigator does not assign exposures?
An observational study
What kind of study is cohort study?
An observational study
What is a cohort?
A cohort is defined as a population group, or subset thereof, that is followed over a period of time.
Cohort group members experience a common exposure associated with a specific setting (occupational cohort or a school cohort) or they share a non-specific exposure associated with a general classification (birth cohort).
What is the cohort effect?
the influence of membership in a particular cohort
like Tobacco use
What is cohort analysis?
The tabulation and analysis of morbidity or mortality rates in relationship to the ages of a specific group of people (cohort) identified at a particular period of time and followed as they pass through different ages during part or all of their life span.
What did Wade Hampton Frost do for Epi?
He popularized cohort analysis method
He arranged tuberculosis mortality rates in a table with age on one axis and year of death on the other
What do cohort studies start with?
Start with a group of subjects who lack a positive history of the outcome of interest and are at risk for the outcome
Include at least two observational points
Why is it important to include at least two observational points that need to be included when starting a cohort study?
To determine exposure status/eligibility and the number of incident cases
What do cohort studies calculate?
incidence rates
Do cohort studies involve concepts of temporarily?
yes - can be though of as going from cause to effect
Cohort studies involve the collection of what kind of data?
primary data, although secondary data sources are used sometimes for both exposure and disease assessment
What are the cohort design options in timing of data collection?
- Prospective
- Retrospective
- Historical Prospective
What is population-based cohort studies?
The cohort includes either an entire population or a representative sample of the population
these have been used in studies of heart disease
What are exposure-based cohort studies?
overcome limitations of population-based cohort studies, which are not efficient for rare exposures.
Certain groups, such as occupational groups, may have higher exposures than the general population of specific hazards
What are temporal differences in cohort designs?
variations in cohort designs that depend on timing of data collection
