title: Seasonal variability in spontaneous cervical artery dissection.
abstract: We examined the seasonal variability of spontaneous cervical artery dissection (sCAD) by analysing prospectively collected data from 352 patients with 380 sCAD (361 symptomatic sCAD; 305 carotid and 75 vertebral artery dissections) admitted to two university hospitals with a catchment area of 2,200,000 inhabitants between 1985 and 2004. Presenting symptoms and signs of the 380 sCAD were ischaemic stroke in 241 (63%), transient ischaemic attack in 40 (11%), retinal ischemia in seven (2%), and non-ischaemic in 73 (19%) cases; 19 (5%) were asymptomatic sCAD. A seasonal pattern, with higher frequency of sCAD in winter (31.3%; 95% confidence interval (CI): 26.5 to 36.4; p=0.021) compared to spring (25.5%; 95% CI: 21.1 to 30.3), summer (23.5%; 95% CI: 19.3 to 28.3), and autumn (19.7%; 95% CI: 15.7 to 24.1) was observed. Although the cause of seasonality in sCAD is unclear, the winter peaks of infection, hypertension, and aortic dissection suggest common underlying mechanisms.
authors.affiliation: Stroke Unit, University Hospital Perugia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Paciaroni
authors.forename: D
authors.initials: D
authors.lastname: Georgiadis
authors.forename: M
authors.initials: M
authors.lastname: Arnold
authors.forename: J
authors.initials: J
authors.lastname: Gandjour
authors.forename: B
authors.initials: B
authors.lastname: Keseru
authors.forename: G
authors.initials: G
authors.lastname: Fahrni
authors.forename: V
authors.initials: V
authors.lastname: Caso
authors.forename: R W
authors.initials: RW
authors.lastname: Baumgartner
mesh_terms: D000328:Adult; D000784:Aortic Dissection / Q000453:epidemiology; D001014:Aortic Aneurysm / Q000453:epidemiology; D020215:Carotid Artery, Internal, Dissection / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D002544:Cerebral Infarction / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006785:Hospitals, University; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D015994:Incidence; D007239:Infections / Q000453:epidemiology; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination / Q000706:statistics & numerical data; D011446:Prospective Studies; D012307:Risk Factors; D012621:Seasons; D013223:Statistics as Topic; D013557:Switzerland; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial; D020217:Vertebral Artery Dissection / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology