Diseases of the circulatory system (CVD) are the most common causes of death in developed countries. However, the prevalence of CVD varies between countries; for example, the mortality rate in Russia is about four times higher than in Western Europe. In a recent retrospective cohort study it was unexpectedly found that CVD mortality is lower among "Aussiedler" (ethnic Germans from the former Soviet Union) compared to the German population.
This is a case-control study, nested into a recent cohort study of migrants from the former Soviet Union. Relatives of cases and controls themselves were interviewed by telephone using a standardized questionnaire. To estimate relative risks via the odds ratio (OR), a conditional logistic regression procedure was performed.
Commonly known risk factors for CVD were identified as relevant to Aussiedler. The best multivariate model for CVD includes five risk factors: consumption of alcohol, smoking, diabetes, cholesterol and consumption of sweets. For alcohol consumption and smoking, OR = 3.68 (95% CI, 1.58-8.58) and OR = 3.07 (95% CI, 1.42-6.62), respectively. For diabetes mellitus and high cholesterol values, OR = 3.29 (95% CI, 1.50-7.39) and OR = 2.32 (95% CI, 1.11-4.88), respectively. The almost complete abdication of sweets is associated with a protective effect, OR = 0.34 (95% CI, 0.18-0.64). The prevalence of risk factors is somewhat different to that of the autochthon German population and partly explains the differences in CVD mortality between both groups.
The reported lower prevalences of known risk factors of CVD such as alcohol consumption, high cholesterol, diabetes and smoking (in women) could contribute to a lower risk of CVD.
Keywords: Nested case-control study, Risk factors, CVD-Mortality, Migrants, Aussiedler, Soviet Union