Nested case–control study

A nested case–control (NCC) study is a variation of a <a href="/facts/Case%25E2%2580%2593control_study/vqzIdkfT">case–control study</a> in which cases and controls are drawn from the population in a fully enumerated <a href="/facts/Cohort_study/Ba0HaJef">cohort</a>.
Usually, the exposure of interest is only measured among the cases and the selected controls. Thus the nested case–control study is more efficient than the full cohort design. The nested case–control study can be analyzed using methods for missing covariates.
The NCC design is often used when the exposure of interest is difficult or expensive to obtain and when the outcome is rare. By utilizing data previously collected from a large cohort study, the time and cost of beginning a new case–control study is avoided. By only measuring the covariate in as many participants as necessary, the cost and effort of exposure assessment is reduced. This benefit is pronounced when the covariate of interest is biological, since assessments such as <a href="/facts/Gene_expression_profiling/BbyYB94G">gene expression profiling</a> are expensive, and because the quantity of blood available for such analysis is often limited, making it a valuable resource that should not be used unnecessarily.

Nested case–control study open-in-new

Nested case–control study