Incidence of first–ever ischemic stroke in the Canton Basle–City, Switzerland
Our study sought to estimate the incidence rate of firstever ischemic stroke (FEIS) in the geographically well–defined population of the Canton Basle–City, Switzerland. An one–year prospective population–based study among the permanent residents of the Canton Basle–City (188015 inhabitants, census 2002) was carried out. Multiple overlapping sources of information were used. Stroke was defined according to the WHO criteria. The diagnosis of FEIS was based on clinical assessment and neuroimaging findings. 269 patients (114 males; mean age 72.8, standard deviation (SD) ± 12 and 155 females; mean age 78.4, SD ± 11) with FEIS were identified. The overall crude incidence of FEIS amounted to 143 per 100000 population (95% confidence interval (CI) 126 to 160) and it was higher among females (156; 95% CI 132 to 181) than in males (128; 95% CI 105 to 152). The age–specific incidence rates of FEIS approximately doubled with each decade of life, increasing from 17 (95 % CI 2 to 31) among 0–44 years old group to 1034 (95% CI 774 to 1293) for those aged 85 or more years. The overall incidence rate of FEIS adjusted for age to the European standard population was 76 per 100000 inhabitants (95% CI 66 to 86) and it was higher in males—89, 95% CI 72–106—than in females—66, 95 % CI 53–77. Moreover, in comparison with studies from other developed countries (e. g. Germany, Italy, Australia)—carried out in the middle of 1990s—the standardised incidence rates of FEIS were substantially lower in Switzerland. Our results indicate that the risk of ischemic stroke might be low in Switzerland. However, giving a major reduction in the age and gender specific stroke incidence over the past years our findings might—alternatively—mirror this favourable trend.