title: Risk factors for Sjögren's syndrome: a case-control study.
abstract: OBJECTIVE
  The aim of this study was to investigate potential risk factors for Sjögren's syndrome (SS) by means of a multi-centre case-control study, focusing in particular on familial and environmental risk factors. 140 female SS patients and 109 female controls with orthopaedic problems were consecutively enrolled in seven university hospitals in Italy.
  
  
  METHODS
  Information regarding the patient's lifestyle, her medical, menstrual and pregnancy history, and any family history of autoimmune diseases (AD) was obtained through a detailed structured questionnaire. The odds ratio (OR) and 95% confidence interval (95%CI) were calculated using unconditional logistic regression, adjusting for age and family size. The probability of first-degree relatives developing an autoimmune disease was also investigated.
  
  
  RESULTS
  A positive family history of AD was significantly associated with SS. Subjects with a first-degree relative (FDR) with AD showed a seven-fold increase in the risk for SS compared to controls (OR=7.4, 95%CI 2.8-20.1); the strength of this association increased with the number of relatives affected. Similarly, the FDR of SS patients had a higher risk of AD in comparison to subjects without FDR affected by SS. Women with one or more pregnancies had an increased risk of SS (OR=2.1, 95%CI 1.0-4.3).
  
  
  CONCLUSIONS
  This study suggests that a family history of AD is associated with SS.
authors.affiliation: Cattedra di Reumatologia, Dipartimento di Clinica e Terapia Medica, Università di Roma, Rome, Italy. rob.pri@libero.it
authors.forename: R
authors.initials: R
authors.lastname: Priori
authors.forename: E
authors.initials: E
authors.lastname: Medda
authors.forename: F
authors.initials: F
authors.lastname: Conti
authors.forename: E A M
authors.initials: EA
authors.lastname: Cassarà
authors.forename: M G
authors.initials: MG
authors.lastname: Sabbadini
authors.forename: C M
authors.initials: CM
authors.lastname: Antonioli
authors.forename: R
authors.initials: R
authors.lastname: Gerli
authors.forename: M G
authors.initials: MG
authors.lastname: Danieli
authors.forename: R
authors.initials: R
authors.lastname: Giacomelli
authors.forename: M
authors.initials: M
authors.lastname: Pietrogrande
authors.forename: G
authors.initials: G
authors.lastname: Valesini
authors.forename: M A
authors.initials: MA
authors.lastname: Stazi
mesh_terms: D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000209:etiology; D016022:Case-Control Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010375:Pedigree; D017584:Reproductive History; D012307:Risk Factors; D012859:Sjogren's Syndrome / Q000453:epidemiology / Q000235:genetics*; D012907:Smoking