Epidemiology of transient ischemic attack.

Few epidemiologic data are available regarding the prevalence and incidence of transient ischemic attack (TIA). Here, the incidence of TIA and that of subsequent stroke events were reviewed. The incidences of TIA in Europe were 0.52-2.37 and 0.05-1.14 in men and women aged 55-64, 0.94-3.39 and 0.71-1.47 in those aged 65-74, and 3.04-7.20 and 2.18-6.06 in those aged 75-84, respectively. The corresponding incidences are similar in the United States, and lower in Japan. Higher incidences were revealed in men compared with women. The incidence of TIA increased very markedly with age, regardless of race or gender. The evidence of risk factors for TIA excluding ischemic strokes is very limited. The ABCD/ABCD(2) score was developed to predict individual risk and to triage patients on the first presentation. In prognostic TIA, the crude rate of stroke risks (%) for general populations were 1.7, 4.8, 6.6, 8.5, and 11.4 at 2 days, 1 week, 1 month, 3 and 6 months, whereas those for hospital patients were 13.7 and 12.4 at 1 and 3 months, respectively. There is very limited evidence of an association between a family history of stroke and the incidence of stroke after TIA, which showed that family history of stroke does not predict the risk of ischemic stroke after TIA. There is also limited evidence of seasonal variation in TIA incidence. TIAs were reported to be most frequent in autumn or spring and less common in winter or spring to summer, and most frequent on Mondays. There seems to be no consensus regarding seasonal differences in TIA incidence.