title: Association of traumatic brain injury with subsequent neurological and psychiatric disease: a meta-analysis.
abstract: OBJECTIVE
  Mild traumatic brain injury (TBI) has been proposed as a risk factor for the development of Alzheimer's disease, Parkinson's disease, depression, and other illnesses. This study's objective was to determine the association of prior mild TBI with the subsequent diagnosis (that is, at least 1 year postinjury) of neurological or psychiatric disease.
  
  
  METHODS
  All studies from January 1995 to February 2012 reporting TBI as a risk factor for diagnoses of interest were identified by searching PubMed, study references, and review articles. Reviewers abstracted the data and assessed study designs and characteristics.
  
  
  RESULTS
  Fifty-seven studies met the inclusion criteria. A random effects meta-analysis revealed a significant association of prior TBI with subsequent neurological and psychiatric diagnoses. The pooled odds ratio (OR) for the development of any illness subsequent to prior TBI was 1.67 (95% CI 1.44-1.93, p < 0.0001). Prior TBI was independently associated with both neurological (OR 1.55, 95% CI 1.31-1.83, p < 0.0001) and psychiatric (OR 2.00, 95% CI 1.50-2.66, p < 0.0001) outcomes. Analyses of individual diagnoses revealed higher odds of Alzheimer's disease, Parkinson's disease, mild cognitive impairment, depression, mixed affective disorders, and bipolar disorder in individuals with previous TBI as compared to those without TBI. This association was present when examining only studies of mild TBI and when considering the influence of study design and characteristics. Analysis of a subset of studies demonstrated no evidence that multiple TBIs were associated with higher odds of disease than a single TBI.
  
  
  CONCLUSIONS
  History of TBI, including mild TBI, is associated with the development of neurological and psychiatric illness. This finding indicates that either TBI is a risk factor for heterogeneous pathological processes or that TBI may contribute to a common pathological mechanism.
authors: Departments of 1 Neurology and.
authors: David C
authors: DC
authors: Perry
authors: Departments of 1 Neurology and.
authors: Virginia E
authors: VE
authors: Sturm
authors: Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center; |Departments of 5 Medicine.
authors: Matthew J
authors: MJ
authors: Peterson
authors: Biostatistics and Bioinformatics, and.
authors: Carl F
authors: CF
authors: Pieper
authors: UCSF School of Medicine, University of California, San Francisco, California;
authors: Thomas
authors: T
authors: Bullock
authors: Department of Neurology, Mayo Clinic, Rochester, Minnesota; and.
authors: Bradley F
authors: BF
authors: Boeve
authors: Departments of 1 Neurology and.
authors: Bruce L
authors: BL
authors: Miller
authors: Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina.
authors: Kevin M
authors: KM
authors: Guskiewicz
authors: Neurosurgery;
authors: Mitchel S
authors: MS
authors: Berger
authors: Departments of 1 Neurology and.
authors: Joel H
authors: JH
authors: Kramer
authors: Psychiatry and Behavioral Sciences, Duke University, Durham, North Carolina;
authors: Kathleen A
authors: KA
authors: Welsh-Bohmer
mesh_terms: D001924:Brain Concussion / Q000473:pathology; D001930:Brain Injuries / Q000150:complications* / Q000523:psychology*; D003704:Dementia / Q000209:etiology; D006801:Humans; D001523:Mental Disorders / Q000209:etiology* / Q000523:psychology*; D009422:Nervous System Diseases / Q000209:etiology* / Q000523:psychology*; D012307:Risk Factors
keywords: ALS = amyotrophic lateral sclerosis; CI = confidence interval; CTE = chronic traumatic encephalopathy; LOC = loss of consciousness; OR = odds ratio; TBI = traumatic brain injury; dementia; head injury; meta-analysis; psychiatry; traumatic brain injury