Obese BMI Tied to Poorer Concussion Recovery in Athletes

The study found that athletes and cadets with a BMI equal to or above 30 had increased inflammatory biomarkers, more severe concussion symptoms and worse cognition following a concussion than those with lower BMI.

These findings support previous research indicating that obesity correlates with increased inflammatory response in patients presenting to the emergency room with a mild traumatic brain injury. The new paper suggests that the same association can also be observed in individuals who exercise regularly and vigorously, underscoring the importance of considering ways to minimize post-concussion inflammation, via dietary changes or aerobic exercise, to aid recovery.

"Body fat is essential for overall health and functioning, but excess amounts can predispose people to higher levels of chronic inflammation, even in athletes," said lead author Shawn Eagle, Ph.D., research assistant professor of neurological surgery at Pitt. "A BMI over 30 is a risk factor that influences post-traumatic inflammation, which, in turn, affects concussion recovery."

BMI is calculated by dividing weight by the square of height. It is used as a screening tool for weight-related health risks, though it does not account for body composition – someone with high muscle mass could have the same BMI as someone carrying excess fat.

Despite its limitations, BMI remains a useful tool for assessing obesity: A recent report showed that more than 98% of adults in the United States who met the criteria for obesity by BMI alone also carried excess fat as measured by more precise methods for assessing body composition, such as whole-body DEXA scan.

To measure the effects of obesity on concussion recovery, Eagle and his team analyzed data collected as part of the Concussion Assessment, Research and Education (CARE) Consortium—a collaboration between the National Collegiate Athletic Association (NCAA) and the U.S. Department of Defense (DOD). The CARE cohort included more than 3,000 individuals from 30 academic and military institutions across the country.

In contrast to earlier research, the new study analyzed repeatedly collected inflammatory blood biomarkers, psychological health scores, concussion symptom severity and cognitive performance before the injury, as well as throughout the recovery process, until individuals were cleared to return to play or participate in military training.

Researchers underscore that their findings do not mean that athletes who carry excess fat need to lose it—but that body composition should be considered when determining the best recovery protocol after a concussion.

"Other groups, including our colleagues at the UPMC Sports Medicine Concussion Program, highlighted that history of migraines, anxiety and depression, or sleep disorders affect concussion recovery," Eagle said. "Our work attempts to understand how pre-injury systemic health could influence recovery."

As a next step in their research, Eagle and team plan to analyze whether body fat distribution, such as visceral fat around the stomach region, is associated with an elevated inflammatory response and health outcomes following brain trauma.

Other authors of this research are David Okonkwo, M.D., Ph.D., of Pitt; Daniel Huber, Michael McCrea, Ph.D., and Timothy Meier, Ph.D., of the Medical College of Wisconsin; Jaroslaw Harezlak, Ph.D., and Thomas McAllister, M.D., of Indiana University; Paul Pasquina, M.D., of the Uniformed Services University of the Health Sciences; Steven Broglio, Ph.D., of the University of Michigan; and the CARE Consortium Investigators.

This research was supported by the National Institute of Neurological Disorders and Stroke (grant R21NS118169), the NCAA, the DOD, and the Office of the Assistant Secretary of Defense for Health Affairs, through the Combat Casualty Care Research Program, endorsed by the DOD, through the Joint Program Committee 6/Combat Casualty Care Research Program–Psychological Health and Traumatic Brain Injury Program (awards W81XWH1420151 and W81XWH1820047).