In one of the largest studies on the association, researchers found people who suffered traumatic brain injuries were more likely to develop dementia and Alzheimer’s disease. Published in The Lancet Psychiatry, researchers studied 2.8 million patient records. They 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 developing dementia by 35%. A single incident of a “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 four or more had a 61% increased chance, and people who suffered five or more had a 183% increased chance.
When 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. While not every person who suffers a single traumatic brain injury or concussion will eventually develop dementia, Fann said the findings may prompt those with histories of such injuries to alter their lifestyles and take control of other risk factors for dementia, including limiting alcohol and tobacco use, increasing exercise, preventing obesity and treating diabetes.