The large number of participants, the nationwide coverage of prospectively recorded registries, and the complete follow-up strengthens the study.
The criminal records registry includes information about all individuals who have been imposed sanctions for committing a crime (Swedish Code of Statutes 1998 620).
Information regarding treatment was recorded after a direct interview on a drug record registry applied at scheduled evaluations [ 28].
For subjects from sites that were current registry users and who matched a registry record, registry managers evaluated whether discrepancies in immunization data existed between the provider record and the registry record.
We reviewed the medical records, registry of demographic characteristics, treatments provided, treatment responses, adverse events, and dates of death.
Only Boston Public Health Commission registry managers had access to individual registry records; registry data provided to Boston University investigators were either aggregated or de-identified.
Our twins were sampled based on information from the Danish Twin Registry and records on birth weight retrieved from the Danish Birth Record Registry for the young twins and from midwife records for the old twins [ 5].
ID, identification number; RRT, indicator of radiation therapy as derived from registry records (registry RT; 0 = RRT-; 1 = RRT+); RT, status of radiation therapy administration as gathered from medical record review (True RT; 0 = TRT-, 1 = TRT+).
