Incidence trends of ischemic stroke and transient ischemic attacks in a well-defined French population from 1985 through 1994

Abstract

Background and Purpose - The changing incidence of ischemic stroke is of major concern in view of its public health impact, to define the population concerned, to identify risk factors, and to set up health-care systems. The aim of this study was to evaluate the time trends associated with the incidence of all the subtypes of ischemic stroke and transient ischemic attacks in a well-defined population for 10 years. Methods - Since 1985, a population registry has recorded each patient living in Dijon (France) who suffered from a cerebrovascular disease (CVD) regardless of the type of management. This study involved all patients suffering from their first ischemic stroke and their first transient ischemic attacks (TIAs) during 1 calendar year between January 1, 1985 and December 31, 1994. The incidence changes according to age, sex, and type of cerebral ischemic event (cortico- subcortical infarct, lacunar infarct, and TIA) were studied on the basis of their annual variations. Results - During the 10-year study period, 834 cortico-subcortical infarcts (52.1%), 296 lacunar infarcts (18.5%), 369 TIAs (23.1%), and 101 undetermined ischemic strokes (6.3%) were collected. The incidence of all ischemic events was relatively stable in both sexes over the 10-year period. However, the incidence rates differed according to age and type of ischemia. An increased incidence of cerebral cortico-subcortical infarct was observed in patients older than 75 years of age (+5.45% annual change [AC] in men, P≤0.05; +5.09% AC in women, NS). In parallel, a higher proportion of emboligenic cardiac arrhythmias was observed in these patients (P≤0.001). The incidence of lacunar infarcts tended to decrease, regardless of age but mainly in men under younger than 75 years of age (-12.74% AC in men, NS; +0.31% AC in women, NS). The incidence of TIAs was relatively stable in both sexes. Because our population consisted of a large number of elderly subjects, the increase in cardioembolic causes could partially explain the increased incidence of cerebral cortico-subcortical infarcts in patients older than 75 years of age. Conclusions - These preliminary data emphasize the importance of stroke surveillance in considering the variations of the different mechanisms of ischemic cerebrovascular disease. Although the incidence of TIA is stable and the incidence of lacunes tends to decrease in men, mainly before 75 years of age, we emphasize the rise of the crude incidence of cortico-subcortical infarcts in men older than 75 years of age, induced by an increase in cardioembolic causes.