Most individuals were identified by name, sex and date of birth. However, many Aussiedler change names during the first years of stay in Germany complicating simple identification by name. To minimize this problem the name matching procedure was done phonetically. For some individuals, city of residence was used as an additional variable to ensure correct identification. 43 cases were excluded from the analysis because they were already diagnosed in their country of origin. All analyses were restricted to the first cancer diagnosis; multiple tumours per individual were not considered
