title: Post-Traumatic Stress Disorder and Risk for Incident Rheumatoid Arthritis.
abstract: OBJECTIVE
  To examine the association between symptoms of post-traumatic stress disorder (PTSD) and rheumatoid arthritis (RA) risk in a prospective cohort and to characterize the role of smoking in this relationship.
  
  
  METHODS
  A subset (n = 54,224) of the Nurses' Health Study II, a prospective cohort of female nurses, completed the Brief Trauma Questionnaire and a screen for PTSD symptoms. Participants were categorized based on trauma exposure and number of PTSD symptoms. Incident RA cases (n = 239) from 1989 to 2011 were identified. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) between PTSD symptoms and incident RA. To identify the impact of smoking, secondary and subgroup analyses were performed. In all analyses, PTSD and smoking were lagged 2 years before the development of RA.
  
  
  RESULTS
  Compared to no history of trauma/PTSD symptoms, the HR for ≥4 PTSD symptoms and incident RA was 1.76 (95% CI 1.16-2.67) in models adjusted for age, race, and socioeconomic status. The risk for RA increased with an increasing number of PTSD symptoms (P = 0.01). When smoking was added to the model, the HR for RA remained elevated (HR 1.60 [95% CI 1.05-2.43]). In a subgroup analysis, excluding women who smoked before PTSD onset, results were unchanged (HR 1.68 [95% CI 1.04-2.70]).
  
  
  CONCLUSIONS
  This study suggests that women with high PTSD symptomatology have an elevated risk for RA, independent of smoking, adding to emerging evidence that stress is an important determinant of physical health.
authors.affiliation: Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Yvonne C
authors.initials: YC
authors.lastname: Lee
authors.affiliation: Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Jessica
authors.initials: J
authors.lastname: Agnew-Blais
authors.affiliation: Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Susan
authors.initials: S
authors.lastname: Malspeis
authors.affiliation: Mailman School of Public Health, Columbia University, New York, New York.
authors.forename: Katherine
authors.initials: K
authors.lastname: Keyes
authors.affiliation: Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Karen
authors.initials: K
authors.lastname: Costenbader
authors.affiliation: Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Laura D
authors.initials: LD
authors.lastname: Kubzansky
authors.affiliation: Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Roberts
authors.affiliation: Mailman School of Public Health, Columbia University, New York, New York.
authors.forename: Karestan C
authors.initials: KC
authors.lastname: Koenen
authors.affiliation: Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Elizabeth W
authors.initials: EW
authors.lastname: Karlson
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000453:epidemiology*; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D015999:Multivariate Analysis; D009726:Nurses; D016272:Occupational Health; D015995:Prevalence; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States / Q000453:epidemiology