title: Seasonal variation in the superficial vein thrombosis frequency.
abstract: BACKGROUND
  A seasonal variation of venous thromboembolic disease frequency is subject to discussion, and has been recently suggested for superficial vein thrombosis (SVT) in a small retrospective study. Our aim was to search for a seasonal variation of SVT frequency according to the data of larger studies.
  
  
  METHODS
  We analyzed the data of three French prospective multicenter studies with different designs which have included patients with SVT (STENOX, POST, and STEPH studies). Seasonal variation of SVT frequency was evaluated by comparing the observed seasonal frequency of SVT to a theoretical frequency of 25% for each season.
  
  
  RESULTS
  The analysis included 1395 patients and 4.75 seasonal cycles. The difference to a theoretical frequency of 25% was statistically significant in one study (POST, p = 0.044). The higher risk difference was -6.1% (95% CI -11.7–−0.5) in summer in STENOX, +7.1% (95% CI +2.7-+11.5) in winter in POST and 4.2% (95% CI -5.2-+13.7) in spring in STEPH, corresponding to a relative risk of 0.80, 1.40 and 1.20, respectively.
  
  
  CONCLUSIONS
  A seasonal variation was found in only one study which has the weakest methodology to warrant completeness. Variation pattern was
authors.affiliation: CIC-EC Inserm, CIE3, CHU Hôpital Nord, Saint-Etienne, France; Département de Médecine Générale, Faculté Jacques Lisfranc, Université Jean Monnet, Saint-Etienne, France; EA3065, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France. Electronic address: paul.frappe@univ-st-etienne.fr.
authors.forename: Paul
authors.initials: P
authors.lastname: Frappé
authors.affiliation: CIC-EC Inserm, CIE3, CHU Hôpital Nord, Saint-Etienne, France; EA3065, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France; Service de Médecine Vasculaire et Thérapeutique, CHU de Saint-Etienne, Saint-Etienne, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bertoletti
authors.affiliation: CIC-EC Inserm, CIE3, CHU Hôpital Nord, Saint-Etienne, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Presles
authors.affiliation: CIC-EC Inserm, CIE3, CHU Hôpital Nord, Saint-Etienne, France; Service de Médecine Vasculaire et Thérapeutique, CHU de Saint-Etienne, Saint-Etienne, France.
authors.forename: Andréa
authors.initials: A
authors.lastname: Buchmuller-Cordier
authors.affiliation: CIC-EC Inserm, CIE3, CHU Hôpital Nord, Saint-Etienne, France.
authors.forename: Adel
authors.initials: A
authors.lastname: Merah
authors.affiliation: Service de Médecine Vasculaire, CHU de Caen, Caen, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Le Hello
authors.affiliation: Département de Médecine Générale, Faculté Jacques Lisfranc, Université Jean Monnet, Saint-Etienne, France; Service de Médecine Vasculaire et Thérapeutique, CHU de Saint-Etienne, Saint-Etienne, France.
authors.forename: Déborah
authors.initials: D
authors.lastname: Peycelon
authors.affiliation: CIC-EC Inserm, CIE3, CHU Hôpital Nord, Saint-Etienne, France; EA3065, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France; Hospitalisation Médicale d'Urgences, CHU de Saint-Etienne, Saint-Etienne, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Tardy
authors.affiliation: CIC-EC Inserm, CIE3, CHU Hôpital Nord, Saint-Etienne, France; EA3065, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France; Service de Médecine Vasculaire et Thérapeutique, CHU de Saint-Etienne, Saint-Etienne, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Décousus
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012621:Seasons; D020246:Venous Thrombosis / Q000453:epidemiology*
keywords: Adult; Chronobiology phenomena; Incidence; Seasons; Thrombophlebitis