Time trends in stroke incidence and in prevalence of risk factors in Southern Germany, 1989 to 2008/09

In prior studies, stroke incidence has mainly shown either declining time trends or stable rates in high-income countries. Changes could partially be linked to trends in classic cardiovascular disease (CVD) risk factors. In the present study, we analyzed the incidence of stroke in parallel with the prevalence of CVD risk factors over time in a German population. Data from three independent population-based MONICA/KORA Augsburg surveys conducted in 1989/90 (S2), 1994/95 (S3), and 1999/2001 (S4) were used to calculate age-standardized incidence rates (IR) of first-ever stroke over eight years from each baseline survey. Furthermore, the age-standardized prevalence rates of CVD risk factors were analyzed for these surveys. Changes in IR or prevalence were considered significantly different if their 95% confidence intervals (CI) did not overlap. The age-standardized IR of stroke showed no significant time trend (S2: IR = 203.4 per 100,000 person-years; CI 176.4–233.4, S3: IR = 225.6; 197.1–257.0, S4: IR = 209.9; CI 182.4–240.3). In agreement, the prevalence of the CVD risk factors was quite stable over time, showing divergent, but mostly non-significant changes. However, due to the aging Western societies and the longer survival time of stroke patients, the total number of stroke patients in the population will increase even with a stable IR.