title: Stability of symptom patterns in Australian Gulf War veterans: 10-year longitudinal study.
abstract: OBJECTIVE
  Previously we established that symptoms reported by 1990-1991 Gulf War veterans were correlated and exhibited a pattern with 3 factors (psychophysiological distress, somatic distress and arthroneuromuscular distress), and this pattern was similar to that observed in a military comparison group. In this follow-up study, we examined whether the patterns of symptomatology have changed over time.
  
  
  METHODS
  Using data on 56 symptoms that was collected in 2000-2003 (wave 1) and 2011-2012 (wave 2) from an Australian cohort of Gulf War veterans (veterans) and a military comparison group, exploratory factor analysis was conducted and Tucker's Congruence Coefficient (TCC) was used to determine factor structure similarity across study groups and waves.
  
  
  RESULTS
  The results showed that the 3 factors observed at wave 1 were still present at wave 2, and factor structures across study groups and study waves were fairly similar, with TCC ranging 0.86-0.92. Veterans consistently reported more symptoms across all 3 factors. Veterans' symptomatology specific to psychophysiological distress increased between waves 1 and 2 (ratio of means 1.15; 95% CI 1.07 to 1.25) but psychophysiological distress symptomatology was constant in the comparison group (ratio of means 0.97; 95% CI 0.89 to 1.06). Somatic and arthroneuromuscular distress symptomatology significantly increased over time for both study groups, although at a similar rate.
  
  
  CONCLUSIONS
  While the symptom groupings (measured by the 3 factors) remained unchanged at 10 years of follow-up, and remained comparable between Gulf War and comparison group, symptomatology continued to be elevated in Gulf War veterans than in the comparison group, and was most evident for psychophysiological distress.
authors.affiliation: School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: S M
authors.initials: SM
authors.lastname: Gwini
authors.affiliation: School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: H L
authors.initials: HL
authors.lastname: Kelsall
authors.affiliation: School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: M R
authors.initials: MR
authors.lastname: Sim
authors.affiliation: School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: J F
authors.initials: JF
authors.lastname: Ikin
authors.affiliation: Centre for Traumatic Stress Studies, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: A C
authors.initials: AC
authors.lastname: McFarlane
authors.affiliation: School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: A B
authors.identifier: http://orcid.org/0000-0002-5512-0830
authors.initials: AB
authors.lastname: Forbes
mesh_terms: D000328:Adult; D001315:Australia / Q000453:epidemiology; D005500:Follow-Up Studies; D047830:Gulf War; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009468:Neuromuscular Diseases / Q000453:epidemiology / Q000209:etiology; D009784:Occupational Diseases / Q000150:complications* / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects*; D018923:Persian Gulf Syndrome / Q000150:complications / Q000453:epidemiology; D015995:Prevalence; D011602:Psychophysiologic Disorders / Q000453:epidemiology / Q000209:etiology; D013001:Somatoform Disorders / Q000453:epidemiology / Q000209:etiology; D014728:Veterans
keywords: Gulf War; factor analysis; occupational disease; syndrome