In the US, the estimated incidence of TIA is approximately 1.2 per 1000 person-years.[2]American College of Radiology. ACR appropriateness criteria: cerebrovascular diseases-stroke and stroke-related conditions. 2023 [internet publication].
https://acsearch.acr.org/docs/3149012/Narrative
[10]Lioutas VA, Ivan CS, Himali JJ, et al. Incidence of transient ischemic attack and association with long-term risk of stroke. JAMA. 2021 Jan 26;325(4):373-81.
https://jamanetwork.com/journals/jama/fullarticle/2775447
http://www.ncbi.nlm.nih.gov/pubmed/33496774?tool=bestpractice.com
TIAs are more common in men than in women, and in black people than in white people.[11]Kleindorfer D, Panagos P, Pancioli A, et al. Incidence and short-term prognosis of transient ischemic attack in a population-based study. Stroke. 2005 Apr;36(4):720-3.
https://www.ahajournals.org/doi/10.1161/01.STR.0000158917.59233.b7
http://www.ncbi.nlm.nih.gov/pubmed/15731465?tool=bestpractice.com
[12]Hosman FL, Engels S, den Ruijter HM, et al. Call to action for enhanced equity: racial/ethnic diversity and sex differences in stroke symptoms. Front Cardiovasc Med. 2022;9:874239.
https://www.frontiersin.org/articles/10.3389/fcvm.2022.874239/full
http://www.ncbi.nlm.nih.gov/pubmed/35592405?tool=bestpractice.com
[13]Amin HP, Madsen TE, Bravata DM, et al. Diagnosis, workup, risk reduction of transient ischemic attack in the emergency department setting: a scientific statement from the American Heart Association. Stroke. 2023 Mar;54(3):e109-21.
https://www.ahajournals.org/doi/full/10.1161/STR.0000000000000418
http://www.ncbi.nlm.nih.gov/pubmed/36655570?tool=bestpractice.com
In a population-based study, Mexican Americans ages between 45 and 59 years were almost twice as likely to experience a TIA as non-Hispanic white people.[14]Morgenstern LB, Smith MA, Lisabeth LD, et al. Excess stroke in Mexican Americans compared with non-Hispanic Whites: the Brain Attack Surveillance in Corpus Christi Project. Am J Epidemiol. 2004 Aug 15;160(4):376-83.
https://academic.oup.com/aje/article/160/4/376/166112
http://www.ncbi.nlm.nih.gov/pubmed/15286023?tool=bestpractice.com
However, at older ages, there were no significant differences.[14]Morgenstern LB, Smith MA, Lisabeth LD, et al. Excess stroke in Mexican Americans compared with non-Hispanic Whites: the Brain Attack Surveillance in Corpus Christi Project. Am J Epidemiol. 2004 Aug 15;160(4):376-83.
https://academic.oup.com/aje/article/160/4/376/166112
http://www.ncbi.nlm.nih.gov/pubmed/15286023?tool=bestpractice.com
The number of TIAs in the US is commonly estimated to be 200,000 to 500,000 per year.[1]Easton JD, Saver JL, Albers GW, et al. Definition and evaluation of transient ischemic attack: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease. The American Academy of Neurology affirms the value of this statement as an educational tool for neurologists. Stroke. 2009 Jun;40(6):2276-93.
https://www.ahajournals.org/doi/full/10.1161/strokeaha.108.192218
http://www.ncbi.nlm.nih.gov/pubmed/19423857?tool=bestpractice.com
However, using the modern tissue-based definition, estimates suggest that there are approximately 120,000 true TIAs each year.[15]Ovbiagele B, Kidwell CS, Saver JL. Epidemiological impact in the United States of a tissue-based definition of transient ischemic attack. Stroke. 2003 Apr;34(4):919-24.
https://www.ahajournals.org/doi/full/10.1161/01.str.0000064323.65539.a7
http://www.ncbi.nlm.nih.gov/pubmed/12637701?tool=bestpractice.com
The exact number of TIAs is difficult to establish with certainty due to the potential for a transient neurologic deficit to be caused by the many conditions that mimic true cerebral ischemia, and because a large number of TIAs go unrecognized.[13]Amin HP, Madsen TE, Bravata DM, et al. Diagnosis, workup, risk reduction of transient ischemic attack in the emergency department setting: a scientific statement from the American Heart Association. Stroke. 2023 Mar;54(3):e109-21.
https://www.ahajournals.org/doi/full/10.1161/STR.0000000000000418
http://www.ncbi.nlm.nih.gov/pubmed/36655570?tool=bestpractice.com
Approximately half never come to medical attention.[16]Giles MF, Flossman E, Rothwell PM. Patient behavior immediately after transient ischemic attack according to clinical characteristics, perception of the event, and predicted risk of stroke. Stroke. 2006 May;37(5):1254-60.
https://www.ahajournals.org/doi/10.1161/01.STR.0000217388.57851.62
http://www.ncbi.nlm.nih.gov/pubmed/16574923?tool=bestpractice.com