A recent study on twins who served in World War II has found a connection between traumatic brain injuries and cognitive decline later in life. The study, published in Neurology, examined the cognitive test scores of individuals who had experienced traumatic brain injuries and found that they were more likely to have lower scores on cognitive tests when they reached about 70 years old. Furthermore, those who had multiple traumatic brain injuries, lost consciousness due to a head injury, or were 25 years or older when the injury occurred experienced a sharper decline in cognition as they aged.
What sets this study apart is its use of a twin-study design. According to Holly Elser, an epidemiologist and resident physician in neurology at the University of Pennsylvania, who peer-reviewed the study, there is robust research on the link between head injuries and cognitive impairment or dementia, but this study is unique in its approach. By comparing identical and fraternal twins, researchers were able to control for some of the underlying genetic factors and early life conditions that may influence cognitive decline.
The study was conducted by Duke University and involved primarily white male twins who were World War II veterans. The participants were born between 1917 and 1927 and were part of a national registry. The researchers spoke with 8,662 people, including 7,188 twin pairs and 1,474 individuals without their twin. Of the twins, 25% reported having at least one traumatic brain injury.
Among the findings, the study revealed that twins with a history of traumatic brain injury and concussions at age 25 or older had lower cognitive test scores later in life. The researchers also found that a loss of consciousness, multiple traumatic brain injuries, and injuries occurring at age 25 or older were associated with a faster rate of cognitive decline in subsequent tests. These associations remained statistically significant even after controlling for factors such as alcohol overuse, smoking, and medical conditions.
However, the study does have some limitations. Participants self-reported their traumatic brain injuries, which may lead to underreporting. Additionally, the study primarily focused on male, white World War II veterans, so the results may not be generalizable to other populations. The researchers also did not analyze the specific causes of the injuries, such as sports-related injuries or injuries sustained during military service.
Despite these limitations, the study emphasizes the importance of taking steps to prevent head injuries. Wearing a helmet and using seat belts are reasonable precautions to minimize the risk of traumatic brain injuries. Furthermore, individuals who have suffered a traumatic brain injury should not feel powerless in preventing cognitive difficulties or dementia as they age. Other modifiable risk factors, such as physical inactivity and poor diet, can also impact cognitive health. Consulting with a healthcare professional for guidance on protecting the brain as one ages is a reasonable step to take.
In conclusion, this study provides valuable insights into the long-term effects of traumatic brain injuries on cognitive decline. By utilizing a twin-study design, researchers were able to control for genetic and early life factors. The findings underscore the importance of preventing head injuries and taking proactive steps to maintain brain health as we age.