Classification of migration background Patients´ clinical and demographic data were retrieved from our database. Migration background was defined according to current law (MighEV §6, Sozialgesetzbuch). In detail this means that migration background is fulfilled, if (1) the person does not possesses the national citizenship, or (2) the origin of birth is outside the borders of the national country, and emigration to the national territory was after 1949, or (3) origin of birth of one of the two parents is outside the current borders of the national territory plus emigration of one of the two parents occured after 1949.