Estimation of a common risk ratio in stratified case-cohort studies

The case-cohort study design is a useful modification of the case-control design, which allows direct estimation of the risk ratio without the rare-disease assumption. While several risk ratio estimation procedures have been proposed under large-strata settings, only the Mantel-Haenszel point estimator is available in sparse stratifications. This paper provides simple confidence limits methods, based on the large-sample distribution of the Mantel-Haenszel risk ratio, that apply to both large-strata and sparse-data situations. For the Tarone risk ratio, I give a new large-strata variance estimate.