title: No association between multiple sclerosis and periodontitis after adjusting for smoking habits.
abstract: OBJECTIVE
  Periodontitis has been reported to be associated with several systemic disorders, and recently a possible relationship with multiple sclerosis (MS) was suggested. The aim of the present study was to investigate the association between periodontitis and MS in a Norwegian cohort.
  
  
  METHODS
  A case-control study in 756 MS patients and 1090 controls was conducted, and logistic regression analysis, adjusting for age, gender, place of residence, mononucleosis and smoking, was performed to investigate the association between MS and periodontitis.
  
  
  RESULTS
  In the unadjusted analysis a higher prevalence of periodontitis was seen in MS patients, but this difference was not statistically significant after adjusting for the covariates.
  
  
  CONCLUSIONS
  The previously suggested association between MS and periodontitis is not supported in this study. Our results underline the importance of adjusting for relevant covariates in epidemiological research.
authors.affiliation: Department of Neurology, Oslo University Hospital, Ullevål, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: M W
authors.initials: MW
authors.lastname: Gustavsen
authors.forename: E G
authors.initials: EG
authors.lastname: Celius
authors.forename: S M
authors.initials: SM
authors.lastname: Moen
authors.forename: A
authors.initials: A
authors.lastname: Bjølgerud
authors.forename: P
authors.initials: P
authors.lastname: Berg-Hansen
authors.forename: G O
authors.initials: GO
authors.lastname: Nygaard
authors.forename: L
authors.initials: L
authors.lastname: Sandvik
authors.forename: B A
authors.initials: BA
authors.lastname: Lie
authors.forename: H F
authors.initials: HF
authors.lastname: Harbo
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology*; D009664:Norway / Q000453:epidemiology; D010518:Periodontitis / Q000453:epidemiology*; D012907:Smoking / Q000453:epidemiology*
keywords: case−control study; epidemiology; inflammation; multiple sclerosis; periodontitis