Sustaining a traumatic brain injury (TBT) in your 20s may increase the risk of developing dementia including Alzheimer's in your 50s by 60 per cent, a review of nearly three million patients has revealed. The findings, published in journal The Lancet Psychiatry, showed that men with traumatic brain injury histories had slightly higher rate of developing dementia (30 per cent vs. 19 per cent) than women. Severe TBI is particularly frequent in young people, and it is concerning that the risk of dementia is particular high in relatively young persons who suffer TBI, said Jakob Christensen, Associate Professor at Aarhus University