Traumatic brain injury (TBI) can nearly double a person's risk for dementia.
“Several studies have now shown that TBI can start an inflammatory cascade in the brain that leads to a much higher risk of dementia and Alzheimer's disease. People with the apoE4 allele, which is the highest known risk factor for Alzheimer's disease besides age, are twice as likely to get Alzheimer's disease than those without apoE4.”