Updated on April 24, 2024.
Traumatic brain injuries (TBIs) are one of the major causes of death in the United States, as well as a big reason for many emergency department (ED) visits and hospitalizations. According to the Centers for Disease Control and Prevention (CDC), in 2020, there were an estimated 214,110 TBI-related hospitalizations in the U.S., and in 2021, more than 69,000 people died from causes related to TBIs.
Despite their prevalence, researchers are still trying to understand the long-term effects of these injuries, including their link to dementia. Though the connections are not fully known, traumatic brain injuries contribute to the risk of developing the degenerative brain condition.
What is a traumatic brain injury?
A TBI occurs when an impact to the head is severe enough to affect regular brain function. TBIs can be penetrating (when something pierces the skull and enters the brain) or blunt (when something hits the head hard but doesn’t penetrate). They are broadly broken down into two main groups: mild TBI and a combined group that includes moderate and severe TBI.
Mild TBI
Mild TBI is the most common form, comprising about 75 percent of TBIs. This category also includes concussions. Mild TBIs may need very little treatment and people who experience them typically recover fully. Some people with mild TBIs, however, may have long-term issues. Mild TBIs may take much longer to heal if a person has had one before. It’s also been shown that people who have had previous concussions are more vulnerable to having another one in the future.
Moderate or severe TBI
People experiencing moderate or severe TBIs may have very serious short- and long-term health conditions, including an elevated risk of infection, among other issues. Besides the immediate dangers caused by the TBI, they may also be at increased risk of deep vein thrombosis (DVT), possibly owing to the effect the TBI has on blood clotting and inflammation. (DVT is a blood clot that forms in a vein deep within the body, such as in the legs.) Treatment for a severe TBI may require stabilization, surgery, and rehabilitation.
What are the symptoms of TBI?
Besides headache, symptoms of a mild TBI may include:
- Difficulty thinking clearly
- Feeling dizzy or nauseous
- Inability to concentrate
- Memory loss
- Anxiety
A person who has experienced a moderate or severe TBI may display the following symptoms:
- Difficulty hearing or seeing
- Aggression
- Sensory perception issues
- Trouble speaking or understanding others
- Loss of consciousness
The connection: TBIs and dementia
Many experts believe TBIs contribute to the risk of developing dementia. A 2022 review published in Biological Psychiatry found that dementia risk increased after sustaining a TBI, especially when a TBI happened in older age.
More research needs to be done to establish a cause-and-effect relationship. Generally speaking, specific diagnoses of neurodegenerative diseases like dementia can only be made after death, when a patient’s brain is examined. Meanwhile, researchers are working on ways to measure risk and monitor dementia more accurately during life.
“The exact mechanism of how TBI increases the risk of developing dementia of all causes is not clear and currently being investigated,” says neurologist Peter Gliebus, MD, the neurology chair at Drexel University College of Medicine and chief of neurology at the Global Neurosciences Institute in Philadelphia.
Who’s at risk for a brain injury?
The leading causes of TBIs are falls, being struck by or against an object, and car accidents. Though head injuries can occur to people of any age, those aged 75 and older are most likely to be hospitalized or die from TBI.
Athletes who play contact sports (such as football or hockey) are at heightened risk of experiencing a TBI, as are cyclists, snowboarders, skiers, and inline skaters. Boxers, football players, and soccer players tend to be singled out when discussing long-term TBI risk because their injuries have been studied most often.
“We have data available from studies that followed athletes, though brain injury acquired during any other activity most likely has the same consequences,” says Dr. Gliebus. “Scientists have already started looking into other patient groups.”
Young athletes are frequently diagnosed with TBIs, too, particularly those who play contact sports. According to the CDC, between 2001 and 2018, contact sports accounted for about 41 percent of the 3.8 million visits children made to EDs for sports-related TBIs. The good news is that the rates of such injuries in kids declined by 32 percent between 2012 and 2018. This is perhaps due in part to a growing awareness of contact-sports-related TBIs.
Ways to prevent TBIs
To help reduce the risk of head injury for yourself and your loved ones—and to reduce the odds of developing dementia down the line—take these precautionary steps:
Buckle up. Always buckle your seat belt in a vehicle and place children in age- and size-appropriate car seats or booster seats.
Drive safely. Never drive when you’ve been drinking or taking drugs.
Wear a helmet. When playing sports, always wear a helmet and other proper safety equipment. This includes:
- Riding a bike or any other type of recreational vehicle
- Playing contact sports
- Skateboarding, skating, skiing, snowboarding, and horseback riding
Child-proof and fall-proof your home. Use window guards, safety gates, and soft playground material around children. Ensure that the home environment is safe and free of clutter, such as from loose rugs or power cords.
Check your vision. Have your eyesight checked each year.
Stay physically fit. Keep up with regular strength and balancing exercises.
If an athlete experiences a concussion or is believed to have had a concussion, they should not play again until medically cleared to do so.
Adopt healthy lifestyle habits to lower risk of dementia
While there is no way to prevent dementia, you can lower your risk of dementia by following these general guidelines prescribed by the CDC:
- Eat a healthy diet that includes fresh fruits and vegetables, whole grains, lean proteins, and healthy fats (such as those in olive oil or seafood). Reduce intake of processed foods and saturated fat (found in red and processed meat and full-fat dairy products.)
- Get regular aerobic exercise, ideally 150 minutes per week of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise.
- Avoid smoking and excessive alcohol.
- Maintain a healthy body weight.
- Maintain social connections.
- Get treatment if you experience depression, hearing or vision loss, high blood pressure, diabetes, or cholesterol.
Taking care of your health in these ways can make a real difference. Almost 40 percent of Alzheimer’s disease and related dementias might be delayed or completely prevented by following a healthy lifestyle and attending to any existing health conditions.
