Difference Between Cohort and Case-Control 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).

1. Is a cohort study a case study?
2. What is the difference between retrospective cohort study and case-control study?
3. Why are cohort studies better than Case-Control?
4. What is the difference between a cohort and cross sectional study?
5. What is an example of a cohort study?
6. Does a cohort study need a control group?
7. How do you identify a cohort study?
8. What type of study is a cohort study?
9. What is an example of a retrospective study?
10. What are the disadvantages of a cohort study?
11. What are the advantages of cohort studies?
12. What is an example of a case control study?

Is a cohort study a case study?

The only difference between cohort studies and case series in many definitions is that cohort studies compare different groups (i.e., examine the association between exposure and outcome), while case series are uncontrolled [3,4,5].

What is the difference between retrospective cohort study and case-control study?

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.

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.

What is the difference between a cohort and cross sectional study?

Cohort studies are used to study incidence, causes, and prognosis. Because they measure events in chronological order they can be used to distinguish between cause and effect. Cross sectional studies are used to determine prevalence.

What is an example of a cohort study?

One famous example of a cohort study is the Nurses' Health Study, a large, long-running analysis of women's health, originally set up in 1976 to investigate the potential long term consequences of the use of oral contraceptives.

Does a cohort study need a control group?

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.

How do you identify a cohort study?

Study Design

A well-designed cohort study can provide powerful results. In a cohort study, an outcome or disease-free study population is first identified by the exposure or event of interest and followed in time until the disease or outcome of interest occurs (Figure 3A).

What type of study is a cohort study?

Cohort studies are a type of longitudinal study—an approach that follows research participants over a period of time (often many years). Specifically, cohort studies recruit and follow participants who share a common characteristic, such as a particular occupation or demographic similarity.

What is an example of a retrospective study?

Retrospective example: a group of 100 people with AIDS might be asked about their lifestyle choices and medical history in order to study the origins of the disease. ... Prospective example: a group of 100 people with high risk factors for AIDS are followed for 20 years to see if they develop the disease.

What are the disadvantages of a cohort study?

Disadvantages of Prospective Cohort Studies

• You may have to follow large numbers of subjects for a long time.
• They can be very expensive and time consuming.
• They are not good for rare diseases.
• They are not good for diseases with a long latency.
• Differential loss to follow up can introduce bias.

What are the advantages of cohort studies?

A major advantage of cohort studies in general is the possibility to study multiple exposures and multiple outcomes in one cohort. Even rare exposures can be studied, for the index group can be selected on this exposure.

What is an example of a case control study?

For example, in a case-control study of the association between smoking and lung cancer the inclusion of controls being treated for a condition related to smoking (e.g. chronic bronchitis) may result in an underestimate of the strength of the association between exposure (smoking) and outcome.