Brain Injuries Linked to Dementia in Later Life Brain Injuries Linked to Dementia In Later Life People who have suffered a traumatic brain injury have a significantly higher risk of dementia, including Alzheimer’s disease than people who have no history of injury, a study suggests. Researchers analysed 2.8 million patient records and found people with a history of brain injury had a 24% higher risk of dementia than those who did not. According to the study, a single traumatic brain injury defined as ‘severe’ increased the risk of developed dementia by 35%. A single incident 'mild’ case or concussion increased the risk by 17%, The number of brain injuries greatly increases the chances of developing dementia or Alzheimer’s disease. People who suffered two or more traumatic brain injuries had a 33% increased chance. People who had suffered for our more had a 61% increased chance and people who suffered five or more had a 183% chance. “What surprised us was that even a single mild TBI associated with a significantly higher risk of dementia,”, lead author Jesse Fann said.” “The relationship between the number of traumatic brain injuries and the risk of dementia was very clear. Similar, a single severe brain injury seems to have twice the risk associated with dementia as a single mild traumatic brain injury” she added. The age at which a person suffers a traumatic brain injury also affects the likelihood of developing dementia. If someone suffers a brain injury in their 20s they are 60% more likely to develop dementia or Alzheimer’s disease in their 50s, according to the findings.