A simulation study of relative efficiency and bias in the nested case-control study design.
Bertke-S; Hein-M; Schubauer-Berigan-M; Deddens-J
Am J Epidemiol 2013 Jun; 177(Suppl 11):S103
Purpose: The nested case-control study design, in which a fixed number of controls are matched to each case, is often used to analyze exposure-response associations within a cohort. It has become common practice to sample 5 - 10 controls per case, however, previous research has shown that in certain instances, significant gains in relative efficiency can be realized when more controls are matched with each case. This study expanded upon these results through a simulation study by also considering a continuous exposure variable as well as investigating potential bias due to small sample sizes. Methods: A simulation study was conducted investigating the effect of the number of cases, strength of exposure-response relation and skewness of exposure variable on bias and relative efficiency. Results: It was shown that relative efficiency decreased and bias away from the null increased as the true exposure-response parameter increased and the skewness of the exposure distribution of the risk-sets increased. This became more pronounced when the number of cases in the cohort was small. Conclusions: Gains in relative efficiency and bias reduction can be realized by sampling more than the 5-10 controls per case generally recommended, especially when there are few cases, a strong exposure-response relation and a skewed exposure variable.
Case-studies; Analytical-instruments; Analytical-processes; Simulation-methods; Occupational-exposure; Employee-exposure; Dose-response; Control-methods; Sampling; Exposure-assessment; Data-processing; Quality-control
American Journal of Epidemiology