title: Risk factors associated with nasopharyngeal cicatrix syndrome in horses.
abstract: OBJECTIVE
  To determine risk factors associated with the development of nasopharyngeal cicatrix syndrome (NCS) in horses.
  
  
  METHODS
  Retrospective case-control study.
  
  
  METHODS
  242 horses referred for endoscopic evaluation of the upper portion of the respiratory tract (121 horses with NCS and 121 control horses).
  
  
  METHODS
  Medical records of horses that had an endoscopic evaluation of the upper airway performed between January 2003 and December 2008 were reviewed. Signalment, housing management, and season of evaluation were recorded and reviewed for each horse. The associations between clinical signs and endoscopic findings were evaluated by the use of a prospective logistic model that included a Bayesian method for inference. Results-Breed and sex had no significant effect on the risk of having NCS. The risk that a horse had NCS increased significantly with age. Exclusive housing in a stall was protective against the development of NCS. In addition, the amount of pasture turnout had a dose-related effect, with exclusive pasture turnout positively correlated with increased risk of developing NCS, compared with a mixture of pasture turnout and stall confinement. Horses were significantly more likely to be evaluated because of clinical signs of the syndrome during the warm months of the year.
  
  
  CONCLUSIONS
  The risk factors for NCS identified in this study may support chronic environmental exposure to an irritant or infectious agent as the cause of NCS. Information gained from this study should be useful for investigating the cause of NCS.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biological Sciences, Texas A&M University, College Station, TX 77843, USA. tnorman@cvm.tamu.edu
authors.forename: Tracy E
authors.initials: TE
authors.lastname: Norman
authors.forename: M Keith
authors.initials: MK
authors.lastname: Chaffin
authors.forename: Wesley T
authors.initials: WT
authors.lastname: Bissett
authors.forename: James A
authors.initials: JA
authors.lastname: Thompson
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D002921:Cicatrix / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D006734:Horse Diseases / Q000209:etiology / Q000473:pathology*; D006736:Horses; D009302:Nasopharyngeal Diseases / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons