Case Control studies - Lecture notes 03
Public health (Khyber Medical University)
Studocu is not sponsored or endorsed by any college or university
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, LECTURE: CASE-CONTROL STUDIES
Learning objectives
By the end of this session, participants should be able to:
1. Understand the basic features of a case-control study and identify their essential elements:
2. Appreciate the strengths and limitations of case-control studies in comparison with other
study designs;
3. Recognize the importance of clearly defining „cases‟ and „controls‟ and of minimizing
potential selection bias;
4. Appreciate the difficulties of obtaining accurate measures of „exposure‟ in this type of study
and be aware of strategies to minimize observer and responder bias;
5. Recognize the importance of collecting information on potential confounders;
6. Understand the advantages and disadvantages of matched and unmatched designs;
7. Grasp how data from case-control studies can be analyzed and recognize which measures of
risk can and cannot be estimated from these studies.
A case-control study starts with the identification of a group of cases (individuals with a
particular illness or condition) and a group of controls (individuals without the illness or
condition). The level, or prevalence, of exposure to factor is then measured in the two groups
and compared. If the prevalence of exposure is higher in the cases than in the controls, the
exposure might be a risk factor for the disease. If it is lower, the exposure might be a
protective factor the disease.
In the past, case-control studies were typically used for chronic diseases (e.g. cancer).
Nowadays, they are being used more and more in infectious diseases and injuries.
1. Conducting a case-control study
1.1 Determination of the hypothesis to be tested
Hypotheses - The specific hypotheses the study is designed to examine must be clearly
stated before details of the design of the study are considered. Failure to do this can lead to
poor design and problems in interpretation of results.
Downloaded by Saud Kakar ()
Public health (Khyber Medical University)
Studocu is not sponsored or endorsed by any college or university
Downloaded by Saud Kakar ()
, LECTURE: CASE-CONTROL STUDIES
Learning objectives
By the end of this session, participants should be able to:
1. Understand the basic features of a case-control study and identify their essential elements:
2. Appreciate the strengths and limitations of case-control studies in comparison with other
study designs;
3. Recognize the importance of clearly defining „cases‟ and „controls‟ and of minimizing
potential selection bias;
4. Appreciate the difficulties of obtaining accurate measures of „exposure‟ in this type of study
and be aware of strategies to minimize observer and responder bias;
5. Recognize the importance of collecting information on potential confounders;
6. Understand the advantages and disadvantages of matched and unmatched designs;
7. Grasp how data from case-control studies can be analyzed and recognize which measures of
risk can and cannot be estimated from these studies.
A case-control study starts with the identification of a group of cases (individuals with a
particular illness or condition) and a group of controls (individuals without the illness or
condition). The level, or prevalence, of exposure to factor is then measured in the two groups
and compared. If the prevalence of exposure is higher in the cases than in the controls, the
exposure might be a risk factor for the disease. If it is lower, the exposure might be a
protective factor the disease.
In the past, case-control studies were typically used for chronic diseases (e.g. cancer).
Nowadays, they are being used more and more in infectious diseases and injuries.
1. Conducting a case-control study
1.1 Determination of the hypothesis to be tested
Hypotheses - The specific hypotheses the study is designed to examine must be clearly
stated before details of the design of the study are considered. Failure to do this can lead to
poor design and problems in interpretation of results.
Downloaded by Saud Kakar ()
