What is a case control or cohort study?
What is a case control or cohort study?
Whereas the cohort study is concerned with frequency of disease in exposed and non-exposed individuals, the case-control study is concerned with the frequency and amount of exposure in subjects with a specific disease (cases) and people without the disease (controls).
What is the difference between retrospective cohort and case control?
While retrospective cohort studies try to compare the risk of developing a disease to some already known exposure factors, a case-control study will try to determine the possible exposure factors after a known disease incidence.
Are case-control studies prospective or retrospective?
Case-control studies are retrospective and cannot therefore be used to calculate the relative risk; this a prospective cohort study. Case-control studies can however be used to calculate odds ratios, which in turn, usually approximate to the relative risk.
What is the difference between a case series and cohort study?
Case series study is descriptive only (no comparison group). It includes group of patients with certain disease or with abnormal sign and symptom. while cohort study include healthy people but they exposed to certain exposure and follow them for certain period to see if the outcome develop or not (incidence study).
How do you identify a case-control and a cohort study?
An important distinction lies between cohort studies and case-series. The distinguishing feature between these two types of studies is the presence of a control, or unexposed, group. Contrasting with epidemiological cohort studies, case-series are descriptive studies following one small group of subjects.
What is a case cohort?
A case-cohort study is similar to a nested case-control study in that the cases and non-cases are within a parent cohort; cases and non-cases are identified at time , after baseline. In a case-cohort study, the cohort members were assessed for risk factros at any time prior to .
Is Case Control A retrospective cohort?
Case-control studies are retrospective. They clearly define two groups at the start: one with the outcome/disease and one without the outcome/disease. They look back to assess whether there is a statistically significant difference in the rates of exposure to a defined risk factor between the groups.
What are the advantages and disadvantages of case control vs cohort studies?
Advantages and disadvantages of cohort and case control studies
| Cohort studies | Case control studies | |
|---|---|---|
| Sample size | Large | Small |
| Cost | Elevated except if retrospective cohorts | Smaller |
| Time required | Long, sometimes very long except if retrospective cohorts | Shorter |
| Follow up | Difficult, loss to follow up | No follow up |
Why are cohort studies better than Case Control?
Cohort studies work well for rare exposures–you can specifically select people exposed to a certain factor. But this design does not work for rare diseases–you would then need a large study group to find sufficient disease cases. Case-control studies are relatively simple to conduct.
Is case-control and case series the same?
A case-series is just a series of cases. The difference between a retrospective case series and a retrospective case-control is that the case series lacks a control group. As such, it is a much weaker design than case-control.
Do cohort studies have control groups?
Cohort studies differ from clinical trials in that no intervention, treatment, or exposure is administered to participants in a cohort design; and no control group is defined. Rather, cohort studies are largely about the life histories of segments of populations and the individual people who constitute these segments.