Advantages and Disadvantages of Cohort and Case-Cotrol Studies

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Certain advantages and disadvantages exist for each of the various study designs. Compare and contrast the advantages and disadvantages of case control and cohort study designs (15 marks).
Comment: In this case, we give advantages and disadvantages of cohort and case control study designs and offer a summary table to bring out their strengths and shortcomings.
Cohort studies
Advantages
1. Allow complete information on the subject’s exposure, including quality control of data, and experience thereafter.
2. Provide a clear temporal sequence of exposure and disease.
3. Give an opportunity to study multiple outcomes related to a specific exposure.
4. Permit calculation of incidence rates (absolute risk) as well as relative risk.
5. Enable the study of relatively rare exposures.
Disadvantages
1. Not suited for the study of rare diseases because a large number of subjects is required.
2. Not suited when the time between exposure and disease manifestation is very long, although this can be overcome in historical cohort studies.
3. Exposure patterns, for example the composition of oral contraceptives, may change during the course of the study and make the results irrelevant.
4. Maintaining high rates of follow-up can be difficult.
5. Expensive to carry out because a large number of subjects is usually required.
6. Baseline data may be sparse because the large number of subjects does not allow for long interviews.
Case-control studies
Advantages
1. Permit the study of rare diseases.
2. Permit the study of diseases with long latency between exposure and manifestation.
3. Can be launched and conducted over relatively short time periods.
4. Relatively inexpensive as compared to cohort studies.
5. Can study multiple potential causes of disease.
Disadvantages
1. Information on exposure and past history is primarily based on interview and may be subject to…...

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