The long-term impact of traumatic brain injury (TBI) on neurologic and psychiatric function is well-established, but a growing body of research is pointing to unexpected medical sequalae, including cardiovascular disease (CVD).
A recent review looked at the investigation to date into this surprising connection, not only summarizing study findings but also suggesting potential mechanisms that might account for the association.
“; consequently, they should undergo regular monitoring,” senior author Ross Zafonte, DO, president of Spaulding Rehabilitation Network, Boston, and lead author Saef Izzy, MD, MBChB, a neurologist at the Stroke and Cerebrovascular Center of Brigham and Women’s Hospital, Boston, Massachusetts, told this news organization.
“This holds significant importance for healthcare practitioners, as there exist several strategies to mitigate cardiovascular disease risk — including weight management, adopting a healthy diet, engaging in regular physical activity, and quitting smoking,” they stated.
Leslie Croll, MD, American Heart Association volunteer and assistant professor of clinical neurology at the Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania, told this news organization that it’s “extremely important to learn more about the interplay between TBI, neurologic disease, psychiatric complications, and the cardiovascular system.”
Hopefully, she added, “future research will help us understand what kind of cardiovascular disease monitoring and prevention measures stand to give TBI patients the most benefit.”
Chronic Condition
TBI is “a major cause of long-term disability and premature death,” and is “highly prevalent among contact sports players, military personnel (eg, due to injuries sustained during conflict), and the general population (eg, due to falls and road traffic incidents),” the authors wrote.
Most studies pertaining to TBI have “primarily focused on establishing connections between single TBI, repetitive TBI, and their acute and chronic neurological and psychiatric consequences, such as Parkinson’s disease, Alzheimer’s disease, and chronic traumatic encephalopathy (CTE),” Drs. Zafonte and Izzy noted. By contrast, there has been a “notable lack of research attention given to non-neurological conditions associated with TBI.”
They pointed out that recent insights into TBI — particularly the acknowledgment of TBI as an “emerging chronic condition rather than merely an acute aftermath of brain injury” — have come to light through epidemiologic and pathologic investigations involving military veterans, professional American-style football players, and the civilian population. “This recognition opens up an opportunity to broaden our perspective and delve into the medical aspects of health that may be influenced by TBI.”
To broaden the investigation, the researchers reviewed literature published between January 1, 2001, and June 18, 2023. Of 26,335 articles, they narrowed their review down to 15 studies that investigated CVD, CVD risk factors, and cerebrovascular disease in the chronic phase of TBI, including community, military, or sport-related brain trauma, regardless of the timing of disease occurrence with respect to brain injury via TBI or repetitive head impact.
New Cardiovascular Risk
Studies that used national or local registries tended to be retrospective and predominantly conducted in people with preexisting cardiovascular conditions. In these studies, TBI was found to be an independent risk factor for myocardial dysfunction. However, although these studies do provide evidence of elevated cardiovascular risk subsequent to a single TBI, including individuals with preexisting medical comorbidities “makes it difficult to determine the timing of incident cardiovascular disease and cardiovascular risk factors subsequent to brain injury,” they wrote.
However, some studies showed that even individuals with TBI but without preexisting myocardial dysfunction at baseline had a significantly higher risk for CVD than those without a history of TBI.
In fact, several studies included populations without preexisting medical and cardiovascular comorbidities to “better refine the order and timing of CVD and other risk factors in individuals with TBI.”
For example, one study of concussion survivors without preexisting diagnoses showed that cardiovascular, endocrinological, and neuropsychiatric comorbidities occurred at a “significantly higher incidence within 5 years after concussive TBI compared with healthy individuals who were matched in terms of age, race, and sex and didn’t have a TBI exposure.” Other studies yielded similar findings.
Because cardiovascular risk factors and events become more common with age, it’s important to account for age in evaluating the effects of TBI. Although many studies of TBI and subsequent CVD didn’t stratify individuals by age, one 10-year study of people without any known cardiovascular or neuropsychiatric conditions who sustained TBI found that people as young as 18-40 years were more likely to develop hypertension, hyperlipidemia, obesity, and diabetes within 3-5 years following brain injury than matched individuals in the control group.
“Individuals who have encountered TBI, surprisingly even those who are young and in good health with no prior comorbid conditions, face an increased risk of adverse cardiovascular outcomes for an extended duration after the initial event,” Drs. Zafonte and Izzy summarized. “Therefore, it’s imperative that they receive regular and long-term screenings for CVD and associated risk factors.”