August 31, 2020
Concussions and dementia: will a concussion increase your risk of dementia later in life?
Recent media focus on the NFL has exposed the dangerous effects of repeated contact sports on the brain. However, the vast majority of football and other contact sport players are children or young adults who play recreationally. At this level, concussions, or brain injuries from impacts, are still very common. Could these injuries affect their brains later in life?
Concussions are the most common brain injury, and the majority stem from sports mishaps, especially in teens. Trends have shown an alarming rise in concussions since the turn of the century. A team of researchers in Ontario, Canada assessed the health insurance records of the entire provincial population under age 18 to quantify hospitalizations from concussions between 2003 and 2013. They also recorded patients' ages and how they got injured.
Hospital visits for concussions increased by 4.4x (95% CI 4.37-4.45) between 2003 and 2013 in the region of Ontario, Canada for kids aged 5-18.
They reported an increase in hospitalizations by more than 4 times. The greatest increase was in teens between 13-18. Those injured reported sports, especially hockey, as the main culprit for the concussion. This data is not alone. Other population studies have found similarly high increases in hospitalization over the past decade.
Increased awareness of brain health in contact sports may explain some of the vigors in hospitalizing and following up with a concussion. Also, an increasing number of children are participating in contact sports, especially in areas that can afford good public school programs. The increased burden of concussions on the young population may lead to some unexpected health consequences down the line.
Research has associated concussions to conditions such as ADHD, depression, anxiety, Parkinson's disease, and dementia, the latter two of which onset much later in life. Dementia is one of the most common conditions affecting the elderly in the US. Researchers sought to formalize the link between concussions and dementia.
The study investigated associations between concussion and the risk of follow-up dementia and Parkinson’s disease.
Researchers matched 47,000 concussion patients, with diagnoses starting in 1990, with up to three non-concussed participants in the Canadian province of Manitoba. These healthy controls were of similar age, sex, health, socioeconomic status, and geographic location. Health records were then tracked up to 2015 when rates of dementia were compared within each matched pair. This allowed 25 years to pass between first concussions and possible dementia diagnosis. At the start of the trial, participants had an average age between 25 and 30.
People who had concussions had a 72% higher chance of dementia diagnosis (HR=1.72; 95% CI 1.61 to 1.84; p<0.001) than comparable people who did not have concussions.
After 25 years, people with concussions had a 72% higher chance of dementia, clearly indicating a long term effect of concussions on brain health. Within the concussion group, as the number of concussions increased, the risk went up.
People who had two concussions had a 62% further chance of dementia diagnosis (HR=1.62; 95% CI 1.25 to 2.10; p<0.001) compared to people who had one concussion.
An additional 62% risk of dementia was added to patients who suffered a second concussion compared to those who suffered just one. This provides stark evidence that further head trauma compounds the latent, and should be avoided if possible.
People who reported concussions were diagnosed with dementia almost 3 years earlier on average
Another alarming discovery from the study was that concussions lowered the age of dementia onset by almost 3 full years. Three years is a huge amount of life for an injury that happened up to 25 years earlier and shows the hidden long term effects of concussive injuries.
This evidence is not to say that your loved ones with concussions are certainly going to get dementia or suffer other brain issues. This was a retrospective study within a specific time period and geographic region, meaning health data before and after the period was inaccessible, and geographic variation can be unpredictable.
The physical and cultural benefits of sports cannot be overstated. Sports are a great means of social bonding, exercise, and escape. However, the correct precautions need to be in place before kids plant the seed for debilitating and potentially preventable brain disorders late in life.