title: Cognitive function and other risk factors for mild traumatic brain injury in young men: nationwide cohort study.
abstract: OBJECTIVE
  To investigate cognitive function and other risk factors for mild traumatic brain injury in young men.
  
  
  METHODS
  Nationwide prospective cohort study.
  
  
  METHODS
  Sweden.
  
  
  METHODS
  305 885 men conscripted for military service from 1989 to 1994.
  
  
  METHODS
  mild traumatic brain injuries in relation to cognitive function and other potential risk factors assessed at conscription and follow-up.
  
  
  RESULTS
  Men with one mild traumatic brain injury within two years before (n=1988) or after cognitive testing (n=2214) had about 5.5% lower overall cognitive function scores than did men with no mild traumatic brain injury during follow up (P<0.001 for both). Moreover, men with at least two mild traumatic brain injuries after cognitive testing (n=795) had 15% lower overall cognitive function scores compared with those with no such injury (P<0.001). Independent strong risk factors (P<1×10(-10)) for at least one mild traumatic brain injury after cognitive testing (n=12 494 events) included low overall cognitive function, a previous mild traumatic brain injury, hospital admission for intoxications, and low education and socioeconomic status. In a sub-cohort of twin pairs in which one twin had a mild traumatic brain injury before cognitive testing (n=63), both twins had lower logical performance and technical performance compared with men in the total cohort with no mild traumatic brain injury (P<0.05 for all).
  
  
  CONCLUSIONS
  Low cognitive function, intoxications, and factors related to low socioeconomic status were strong independent risk factors for mild traumatic brain injuries in men. The low cognitive function in twin pairs discordant for mild traumatic brain injury suggests a genetic component to the low cognitive function associated with such injuries. The study included only men, so inferences to women should be made with caution.
authors.affiliation: Department of Community Medicine and Rehabilitation, Rehabilitation Medicine, Umeå University, SE-901 87 Umeå, Sweden. anna.nordstrom@idrott.umu.se
authors.forename: Anna
authors.initials: A
authors.lastname: Nordström
authors.forename: Benoni B
authors.initials: BB
authors.lastname: Edin
authors.forename: Sara
authors.initials: S
authors.lastname: Lindström
authors.forename: Peter
authors.initials: P
authors.lastname: Nordström
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects; D000435:Alcoholic Intoxication / Q000150:complications; D000465:Algorithms; D001930:Brain Injuries / Q000150:complications* / Q000175:diagnosis*; D003071:Cognition; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000209:etiology*; D015331:Cohort Studies; D004522:Educational Status; D005500:Follow-Up Studies; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008887:Military Medicine; D008889:Military Personnel; D009483:Neuropsychological Tests; D010343:Patient Admission / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012923:Social Class; D013548:Sweden; D018433:Twin Studies as Topic; D055815:Young Adult