title: Traumatic brain injury and age at onset of cognitive impairment in older adults.
abstract: There is a deficiency of knowledge regarding how traumatic brain injury (TBI) is associated with age at onset (AAO) of cognitive impairment in older adults. Participants with a TBI history were identified from the Alzheimer's disease neuroimaging initiative (ADNI 1/GO/2) medical history database. Using an analysis of covariance (ANCOVA) model, the AAO was compared between those with and without TBI, and potential confounding factors were controlled. The AAO was also compared between those with mild TBI (mTBI) and moderate or severe TBI (sTBI). Lastly, the effects of mTBI were analyzed on the AAO of participants with clinical diagnoses of either mild cognitive impairment (MCI) or Alzheimer's disease (AD). The AAO for a TBI group was 68.2 ± 1.1 years [95 % confidence interval (CI) 66.2-70.3, n = 62], which was significantly earlier than the AAO for the non-TBI group of 70.9 ± 0.2 years (95 % CI 70.5-71.4, n = 1197) (p = 0.013). Participants with mTBI history showed an AAO of 68.5 ± 1.1 years (n = 56), which was significantly earlier than the AAO for the non-TBI group (p = 0.032). Participants with both MCI and mTBI showed an AAO of 66.5 ± 1.3 years (95 % CI 63.9-69.1, n = 45), compared to 70.6 ± 0.3 years for the non-TBI MCI group (95 % CI 70.1-71.1, n = 935) (p = 0.016). As a conclusion, a history of TBI may accelerate the AAO of cognitive impairment by two or more years. These results were consistent with reports of TBI as a significant risk factor for cognitive decline in older adults, and TBI is associated with an earlier AAO found in patients with MCI or AD.
authors.affiliation: School of Health and Rehabilitation Sciences, Indiana University Purdue University, 2039 N. Capitol Avenue, Indianapolis, IN, 46202, USA. wl23@iu.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Radiology and Imaging Sciences, Center for Neuroimaging, Indiana Alzheimer Disease Center, Indiana University School of Medicine, 355 W. 16th Street, Suite 4100, Indianapolis, IN, 46202, USA.
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Risacher
authors.affiliation: Department of Psychiatry, Indiana University School of Medicine, 355 W. 16th Street, Suite 4800, Indianapolis, IN, 46202, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: McAllister
authors.affiliation: Department of Radiology and Imaging Sciences, Center for Neuroimaging, Indiana Alzheimer Disease Center, Indiana University School of Medicine, 355 W. 16th Street, Suite 4100, Indianapolis, IN, 46202, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Saykin
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000070642:Brain Injuries, Traumatic / Q000150:complications*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D015599:Trauma Severity Indices
keywords: Age at onset; Alzheimer's disease; Dementia; MCI; Traumatic brain injury