The Design and Methods of the Nested Case-Control Studies

The importance of cohort studies in order to explore diseae causes has been recognized. When a disease is rare, the cohort studies need a long follow-up period, a high budget, and a large number of participants in the target population. A nested case-control study design is proposed as a supplementary study conducted within a cohort, efficiently using the information from the cohort study. In the present paper we explain the sampling design of controls and the methods of data analysis in a nested case-control study. In addition we explain the methods of sample size and power calculation to design the nested case-control study. Further, we introduce some methods for the data with missing values in covariates, and we report the performance assessment from the application of these methods to the nested case-control study data.