a new study suggests.
Among more than 4,000 participants, 37% had hypertension at a median of 24 years post career and reported a median concussion symptom score (CSS) of 23 on a scale of 0 to 130.
“We have long seen an incompletely explained link between football participation and later-life cardiovascular disease,” Aaron L. Baggish, MD, of Massachusetts Hospital and Harvard Medical School, Boston, told this news organization.
“This study tested [whether] concussion burden during years of active play would be a determinant of later-life hypertension, the most common cause of cardiovascular disease, and indeed found this relationship to be a strong one.”
The study was published online in Circulation.
Link to cognitive decline?
Dr. Baggish and colleagues recruited former professional American-style football (ASF) players to participate in a survey administered by the Football Players Health Study at Harvard University.
Concussion burden was quantified with respect to the occurrence and severity of common concussion symptoms – e.g., headaches, nausea, dizziness, confusion, loss of consciousness (LOC), disorientation, and feeling unsteady on one’s feet – over years of active participation.
Prevalent hypertension was determined either by the participants’ previously receiving from a clinician a recommendation for medication for “high blood pressure” or by the participants’ taking such medication at the time of survey completion. Diabetes status was determined by the participants’ receiving a prior recommendation for or prescription for “diabetes or high blood sugar” medication.
Of 15,070 invited to participate in the study, 4,168 did so. The mean age of the participants was 51.8 years; 39.4% were Black; the mean body mass index was 31.3; and 33.9% were linemen. Participants played for a mean of 6.9 seasons and were surveyed at a median 24.1 years post ASF career completion. The median CSS was 23.
A total of 1,542 participants (37.3%) had hypertension, and 8.8% had diabetes.
After adjustment for established hypertension risk factors, including smoking, race, diabetes, age, and BMI, there was a graded association between CSS category and odds of later-life hypertension and between high CSS exposure and prevalent hypertension.
Results persisted when LOC, a single highly specific severe concussion symptom, was used in isolation as a surrogate for CSS, the investigators noted.
“These results suggest that repetitive early-life brain injury may have later-life implications for cardiovascular health,” they wrote. They also noted that hypertension has been shown to independently increase the risk of cognitive decline.
While premature cognitive decline among ASF players is generally attributed to chronic traumatic encephalopathy, “data from the current study raise the possibility that some element of cognitive decline among former ASF players may be attributable to hypertension,” which is potentially treatable.
“Future studies clarifying associations and causal pathways between brain injury, hypertension, and brain health are warranted,” they concluded.
Dr. Baggish added, “We hope that clinicians will now understand that head injury is an independent risk factor for high blood pressure and will screen vulnerable populations accordingly, as this may lead to better recognition of previously underdiagnosed hypertension with subsequent opportunities for intervention.”
Close monitoring
Commenting on the study, Jonathan Kim, MD, chair-elect of the American College of Cardiology’s Sports–Cardiology Section and chief of sports cardiology at Emory University in Atlanta, said, “They clearly show an independent association, which is not causality but is a new finding that requires more research. To me, it really emphasizes that cardiovascular risk is the most important health consequence that we should be worried about in retired NFL [National Football League] players.
“There are multifactorial reasons – not just repetitive head trauma – why this athletic population is at risk for the development of high blood pressure, even among college players,” he said.
Dr. Kim’s team has shown in studies conducted in collaboration with Dr. Baggish and others that collegiate football players who gain weight and develop increased systolic blood pressure are at risk of developing a “pathologic” cardiovascular phenotype.
Other research from this group showed links between nonsteroidal anti-inflammatory drug use among high school and collegiate ASF players and increased cardiovascular risk, as well as ASF-associated hypertension and ventricular-arterial coupling.
The suggestion that late-life hypertension could play a role in premature cognitive decline among ASF players “warrants further study,” Dr. Kim said, “because we do know that hypertension in the general population can be associated with cognitive decline. So that’s an important future direction.”
He concluded: “It’s a matter of focusing on cardiac prevention.” After their careers, players should be counseled on the importance of losing weight and adopting heart-healthy habits. In addition to some of the traditional concerns that might lead to closer follow-up of these patients, “having a lot of concussions in the history could potentially be another risk factor that should warrant close monitoring of blood pressure and, of course, treatment if necessary.”
The study was supported by Harvard Catalyst/the Harvard Clinical and Translational Science Center and the NFL Players Association. Dr. Baggish and several coauthors have received funding from the NFL Players Association.
A version of this article originally appeared on Medscape.com.