Question

1. What are the assumptions in a case-control study?

2. Should we use incident or prevalent cases? Are the endometrial cancer cases in any study are incident or prevalent?

Answer 1

Case control study

Important type of study in observational research. Due to it's speed and efficiency, the case control study is often the first design of choice in studies on the etiology of disease. Case control study is essential if the disease is rare and or assessment of the exposure is expensive, and in situations where results are needed quickly to inform public health policy.

Assumptions in a case control study

case control study mainly employed in study to assess a rare disease. It's assumption mainly includes the contributing factors to cause a disease in a community. It's a retrospective study which the researcher tried to establish a relationship between the factors or habits which contributes to disease.

Case control studies may use incident or prevalent cases.

Incident cases

Comprise cases newly diagnosed in a defined period. The use of incident cases is preferential, as recall of past exposure is accurate among newly diagnosed cases. In addition, temporal sequences of exposure and disease is easier to assess among incident cases.

Prevalent cases

Including prevalent cases is tempting,as it will increase pool of potential cases. However, there are number of biases in them, incident cases are more preferred.

Endometric Cancer cases in any study is a prevalent study. Because, here the newly diagnosed cases are indicated, not the risk of population to develop the disease.Prevsnce is the burden of a disease in a population. In this case, it may increse the potential cases.