1. Comparison of Risk Factors for Early-Onset versus Late-Onset Alzheimer Disease OBJECTIVE To compare early-onset (before 65) Alzheimer disease (AD) patients with late-onset AD patients with respect to vascular risk factors, depression, excessive use of alcohol, traumatic brain injury (TBI), education, and family history of dementia. BACKGROUND Previous studies have identified cerebrovascular disease, hypertension, type 2 diabetes mellitus, obesity, smoking, depression, and traumatic brain injury as potential risk factors for AD. Less is known about risk factors that contribute to the development of AD prior to age 65. Identification of risk factors for early-onset AD can lead to an improved understanding of disease pathophysiology, eventually leading to development of preventative measures against AD. METHODS This was a retrospective chart review from a university dementia clinic from 9/1/10 to 9/1/13. The clinical diagnosis of AD was made according to criteria of McKhann et al, 2011. Neuroimaging tests and laboratory screening tests were performed according to AAN guidelines. Ugur Sener, MD; Linda Hershey, MD PhD; Calin Prodan, MD; Jennifer Lippoldt, MPH Department of Neurology, University of Oklahoma Medical Center; Oklahoma City, OK Email: sener.ugur@mayo.edu Last Edited: July 22, 2014 Conclusion: Mild TBI two years or more before the initial diagnosis of dementia was more common in patients with early-onset AD, compared to those with late-onset AD. RESULTS We identified 35 patients with early-onset AD and 103 patients with late-onset AD during the study period. Seven of the 35 early-onset AD patients had experienced concussion two years or more before their initial visit, compared to 5 of the 103 late-onset AD patients (p=0.0116, Fisher’s exact test, Fig 1 and Fig 2). There were no significant differences in any of the other risk factors. Author Disclosures: Dr. Hershey’s Study Support: Baxter, Forum, NIH, OCNS, OU Health Sciences Center, Norman Faculty Investment Program, Singer Foundation Fig 1: History of concussion was the only risk factor that was significantly more common in the early-onset AD group. Fig. 2 Decline of MMSE scores after a minimum of 9- month follow-up among those with and without epilepsy revealed a significantly more rapid decline in the epilepsy group Fig. 3 Time to event curves showing a shorter time course of dementing illness before the development of seizures among those patients with vascular dementia compared with those who had Alzheimer’s disease Risk Factor Investigated Early-Onset (n=35) Late-Onset (n=103) Two-sided p-value BMI 25-29.915350.4126 BMI ≥ 309200.4725 BMI ≥ 40220.2665 Family History24610.4217 Education ≤ 12 Yrs11420.3161 Stroke3160.4012 Diabetes6110.3727 Hypertension21740.2096 Depression21601 Concussion750.0116 Alcohol Excess480.4996 Smoking History15310.2131 Age at Index Visit Gender Early-Onset AD Type of Head Injury 69Female Head injury with loss of consciousness in 1997 64Female Head injury with loss of consciousness in 1950 63Female Motor vehicle accident in 1983 59Male History of four concussions since age 13 58Female Motor vehicle accident at age 5 51Male Multiple concussions while playing football in the 1970s 65Female Head injury with loss of consciousness in 2010 74FemaleX Motor vehicle accident in 1997 81FemaleX Head injury with loss of consciousness in 2011 83MaleX History of three concussions between 2009 and 2011 78MaleX Motor vehicle accident in 1940s 90MaleX Injury details unknown Fig 2: Description of head injuries documented in patients with early-onset and late-onser AD. M1322