Kuhrs et al. BMC Public Health 2012, 12:190 http://www.biomedcentral.com/1471-2458/12/190 Page 2 of 9 Figure 1 The number of ethnic Germans for Countries of origin 1950-2009. Excerpt from the Federal Administrative Office, Annual Statistics 2009, p. 5. An investigation based on cooperative health research in the Augsburg region (KORA study) [4] shows that migrants assess their health as poorer, that they partici- pate inadequately in measures of health care and that they are more likely to be overweight and less physically active than Germans. After the collapse of the Soviet Union, the death rate among Russians increased rapidly [10-14]. In 2007, the total mortality of the population in Russia was 1465 per 100,000 inhabitants. Of these, more than 50% were caused by diseases of the circulatory sys- tem (ICD10 -I00-I99) [15]. Low socio-economic status was associated with increased cardiovascular mortality in many studies in different populations [16-18]. Because of the high cardiovascular mortality in the Rus- sian population and the generally low socio-economic status of migrants, it has been suggested that cardiovas- cular mortality should be greater among Aussiedler than among the native Germans [19]. However, in a recent retrospective cohort study it was shown that the cardio- vascular mortality among Aussiedler was not only lower in comparison to the mortality in Russia, but also lower in comparison to the mortality of the general population of Germany with a standardized mortality ratio, SMRcvd, of 0.79 [95%-CI 0.73-0.85] [11,4]. The aim of this study is to identify and to quantify cardiovascular and cerebrovascular diseases risk factors, and to compare the prevalence of these factors to that of the German population. Materials and methods Study design and study population This is a case-control study, nested into a recent cohort study of migrants from the former Soviet Union [4]. The original cohort consists of 34,393 out of 281,356 migrants with the age of at least 15 years at entry to North Rhine-Westphalia (NRW) in the period between 01.01.1990 and 31.12.2001 for whom an automated record linkage with the population registry of their first residence was possible (for the detailed description of the cohort see [5,20]). For the present nested case-con- trol study, all deaths from cardiovascular diseases within the cohort were considered. Figure 2 describes the selec- tion of cases and controls from the original cohort. Until the end of the follow-up on 31.12.2005, 1077 deaths from cardiovascular diseases (International Statis- tical Classification of Diseases and Related Health Pro- blems ICD10 - I00-I99) were observed. The causes of death were coded according to ICD-9 and ICD-10 depending on year of death. For 404 cases, one or more relatives were available within the cohort. To ensure comparability between cases and controls, cases were matched using the propensity score [21-24] by year of birth, immigration year, and gender. A 1:4 matching was originally planned, however, an insufficient number of potential controls were available for several cases which fulfilled the matching criteria. A total of 680 controls from the original cohort were selected from all survivors