title: Head trauma and in vivo measures of amyloid and neurodegeneration in a population-based study.
abstract: OBJECTIVE
  We determined whether head trauma was associated with amyloid deposition and neurodegeneration among individuals who were cognitively normal (CN) or had mild cognitive impairment (MCI).
  
  
  METHODS
  Participants included 448 CN individuals and 141 individuals with MCI from the Mayo Clinic Study of Aging who underwent Pittsburgh compound B (PiB)-PET, fluorodeoxyglucose-PET, and MRI. Head trauma was defined as a self-reported brain injury with at least momentary loss of consciousness or memory. Regression models examined whether head trauma was associated with each neuroimaging variable (assessed as continuous and dichotomous measures) in both CN and MCI participants, controlling for age and sex.
  
  
  RESULTS
  Among 448 CN individuals, 74 (17%) self-reported a head trauma. There was no difference in any neuroimaging measure between CN subjects with and without head trauma. Of 141 participants with MCI, 25 (18%) self-reported a head trauma. MCI participants with a head trauma had higher amyloid levels (by an average 0.36 standardized uptake value ratio units, p = 0.002).
  
  
  CONCLUSIONS
  Among individuals with MCI, but not CN individuals, self-reported head trauma with at least momentary loss of consciousness or memory was associated with greater amyloid deposition, suggesting that head trauma may be associated with Alzheimer disease-related neuropathology. Differences between CN individuals and individuals with MCI raise questions about the relevance of head injury-PET abnormality findings in those with MCI.
authors.affiliation: From the Divisions of Epidemiology (M.M.Mielke, R.O.R., R.C.P., Y.E.G.) and Biomedical Statistics and Informatics (H.J.W., S.D.W.), Department of Health Sciences Research; Departments of Neurology (R.S., D.S.K., R.O.R, R.C.P.), Psychiatry and Psychology (M.M.Machulda), and Radiology (P.V., V.J.L, C.R.J.), Mayo Clinic, Rochester, MN; and Departments of Psychiatry, Psychology, and Neurology (Y.E.G.), Mayo Clinic, Scottsdale, AZ.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Mielke
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Savica
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Wiste
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Weigand
authors.forename: Prashanthi
authors.initials: P
authors.lastname: Vemuri
authors.forename: David S
authors.initials: DS
authors.lastname: Knopman
authors.forename: Val J
authors.initials: VJ
authors.lastname: Lowe
authors.forename: Rosebud O
authors.initials: RO
authors.lastname: Roberts
authors.forename: Mary M
authors.initials: MM
authors.lastname: Machulda
authors.forename: Yonas E
authors.initials: YE
authors.lastname: Geda
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Petersen
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Jack
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D006259:Craniocerebral Trauma / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D019636:Neurodegenerative Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D058225:Plaque, Amyloid / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D011159:Population Surveillance / Q000379:methods*