Head injuries in the United States are alarmingly common. About 23 million people in the U.S. over the age of 40 report suffering some type of head injury. A new study reports that some of those people – especially those with multiple head injuries – may have an increased risk of developing dementia later in life.
The study associated a higher risk for developing dementia with a larger number of head injuries. The study authors also note that despite the troubling findings of their research, many head injuries can be prevented by taking precautions when playing contact sports, driving a car, riding a bike or engaging in other activities where head injuries often occur.
“Head injury is a significant risk factor for dementia, but it’s one that can be prevented. Our findings show that the number of head injuries matter – more head injuries are associated with greater risk for dementia,” said Schneider, an assistant professor of Neurology at the University of Pennsylvania. “The dose-dependence of this association suggests that prevention of head injury could mitigate some risk of dementia later in life.”
A Single Head Injury Associated with Higher Dementia Risk
Researchers from the University of Pennsylvania conducted the study, gathering data from a diverse group of patients. The cohort had a mean baseline age of 54, with 56% of them women and 27% of them Black. Researchers followed the group for a median time of 25 years, which include six in-person visits and semi-annual telephone follow-ups.
Hospital records supplied data on each patient, with some of them also self-reporting. To determine the significance of head injuries on dementia, the researchers compared data between those who suffered at least one traumatic brain injury and those who did not.
The study associated those with a single prior head injury with a 1.25 increased chance for developing dementia. Those with two or more injuries had a two times increased risk of dementia. Overall, the researchers associated 9.5% of dementia cases among the study population to at least one previous head injury.
The Risk Is Higher For Women, White People
No previous study had investigated the relative impact of head injuries on dementia risk along racial and gender lines. The results in the University of Pennsylvania study found that women stood a higher chance of developing dementia after a head injury than men.
Further, while the risk of dementia is higher for both Black and white people who endure a head injury, white participants in the study had a higher risk than Black participants.
Given the increased dementia risk for those who suffer even one head injury, the study authors emphasized the need for preventative measures. “There is an important need for future research focused on prevention and intervention strategies aimed at reducing dementia after head injury,” Schneider said.
The study already has led to research projects that are focusing on learning exactly how head injuries cause dementia and the underlying reasons for the disparity in outcomes for different races and genders.