title: Incidence of adult onset schizophrenic disorders in the US military: patterns by sex, race and age.
abstract: BACKGROUND
  There are limited data describing the epidemiology of adult-onset schizophrenic disorders in the United States. Although the military is not proportionately comparable in all demographic characteristics to the civilian population, it is drawn from all racial/ethnic subgroups, and members range in age from 17 to >60 years. We describe the incidence of hospitalization for new onset schizophrenic disorders among military members by sex, race, and age.
  
  
  METHODS
  Using military inpatient data, we evaluated patterns of initial hospitalizations for schizophrenic disorders among military personnel for 2000-2009, focusing on sex, race, and age. No individual-level data were available.
  
  
  RESULTS
  From 2000-2009, 1976 military personnel had a first schizophrenic disorder hospitalization, with an overall incidence rate of 0.14/1000 person-years. There were no consistent changes in rates over time. While overall incidence rates were similar for men and women (incidence rate ratio (IRR)=1.10), rates were higher among men than women below age 25; after 25-30 rates were higher among women. Incidence was higher among blacks and other racial groups, with IRR=2.0 and 1.3, respectively.
  
  
  CONCLUSIONS
  Medical screening of military applicants prevents persons with overt or a reported history of psychosis, and most with serious behavior problems, from enlisting; therefore, first hospitalization is likely to reflect new illness. No pre-military socioeconomic data were available, however, essentially all study subjects were high school graduates; unmeasured differences in socioeconomic status were unlikely to explain the observed results. This report may provide lower bound estimates of the schizophrenic disorder incidence in the United States.
authors.affiliation: Walter Reed Army Institute of Research, Department of Epidemiology, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA. David.Cowan@amedd.army.mil
authors.forename: David N
authors.initials: DN
authors.lastname: Cowan
authors.forename: Natalya S
authors.initials: NS
authors.lastname: Weber
authors.forename: Jared A
authors.initials: JA
authors.lastname: Fisher
authors.forename: Sheryl A
authors.initials: SA
authors.lastname: Bedno
authors.forename: David W
authors.initials: DW
authors.lastname: Niebuhr
mesh_terms: D000367:Age Factors; D016001:Confidence Intervals; D005006:Ethnicity / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008889:Military Personnel / Q000523:psychology / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis* / Q000453:epidemiology*; D012737:Sex Factors; D014481:United States / Q000453:epidemiology