Syncope is estimated to account for approximately 1% of accident and emergency department visits in the US and Europe.[11]Blanc JJ, L'Her C, Touiza A, et al. Prospective evaluation and outcome of patients admitted for syncope over a 1 year period. Eur Heart J. 2002 May;23(10):815-20.
https://academic.oup.com/eurheartj/article/23/10/815/451506
http://www.ncbi.nlm.nih.gov/pubmed/12009722?tool=bestpractice.com
[12]Disertori M, Brignole M, Menozzi C, et al. Management of patients with syncope referred urgently to general hospitals. Europace. 2003 Jul;5(3):283-91.
https://academic.oup.com/europace/article/5/3/283/599679
http://www.ncbi.nlm.nih.gov/pubmed/12842645?tool=bestpractice.com
[13]Runser LA, Gauer RL, Houser A. Syncope: evaluation and differential diagnosis. Am Fam Physician. 2017 Mar 1;95(5):303-12.
https://www.aafp.org/pubs/afp/issues/2017/0301/p303.html
http://www.ncbi.nlm.nih.gov/pubmed/28290647?tool=bestpractice.com
The estimated cumulative lifetime incidence of syncope is 35%.[14]Ganzeboom KS, Mairuhu G, Reitsma JB, et al. Lifetime cumulative incidence of syncope in the general population: a study of 549 Dutch subjects aged 35-60 years. J Cardiovasc Electrophysiol. 2006 Nov;17(11):1172-6.
http://www.ncbi.nlm.nih.gov/pubmed/17074006?tool=bestpractice.com
It tends to peak in frequency in young adults and then again in older people.[15]Ruwald MH, Hansen ML, Lamberts M, et al. The relation between age, sex, comorbidity, and pharmacotherapy and the risk of syncope: a Danish nationwide study. Europace. 2012 Oct;14(10):1506-14.
https://academic.oup.com/europace/article/14/10/1506/448196
http://www.ncbi.nlm.nih.gov/pubmed/22588456?tool=bestpractice.com
Vasovagal syncope is the most common cause of syncope.[16]Saklani P, Krahn A, Klein G. Syncope. Circulation. 2013 Mar 26;127(12):1330-9.
https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.112.138396
http://www.ncbi.nlm.nih.gov/pubmed/23529534?tool=bestpractice.com
Most studies suggest that women (especially younger women) are more susceptible to vasovagal faints, although reporting bias may play a role, as young men may be less inclined to report such events.
The highest frequency of syncope is in patients with cardiovascular comorbidity and in older patients aged >70 years.[17]Lipsitz LA, Wei JY, Rowe JW. Syncope in an elderly institutionalised population: prevalence, incidence, and associated risk. Q J Med. 1985 Apr;55(216):45-54.
http://www.ncbi.nlm.nih.gov/pubmed/4011842?tool=bestpractice.com
[18]Soteriades ES, Evans JC, Larson MG, et al. Incidence and prognosis of syncope. N Engl J Med. 2002 Sep 19;347(12):878-85.
https://www.nejm.org/doi/full/10.1056/NEJMoa012407
http://www.ncbi.nlm.nih.gov/pubmed/12239256?tool=bestpractice.com
In older people, the quoted prevalence figures for syncope are probably an underestimate, because historical features may be less clear-cut and up to 20% of these patients have amnesia.