Feasibility of nationwide birth registry control selection in the United States.

As random digit dialing becomes increasingly unfeasible for many types of studies, alternative methods for control selection are needed, especially for studies of childhood cancer. US birth registries are an appealing source of young control children because they are population based, provide demographic and pregnancy data for comparison of participants with the study base, and maintain data that enable matching on birth characteristics. Here the authors describe the ability of US birth registries to release information sufficient to locate potential control subjects for two ongoing case-control studies of hepatoblastoma and infant leukemia. The birth registries of 32 states, in which 75.8% of US children 0-5 years of age resided in 2004, agreed to participate in control selection. Data sufficient to track participants and to characterize nonrespondents were available from a majority of registries. These results suggest that birth registries may be used to select controls for studies of rare childhood diseases on a national scale.