Study – White Matter Signal Abnormalities in Brain “Significantly Greater” In MMA Fighters With Football or Rugby History

An interesting study was published this week in the peer reviewed journal The Physician and Sports Medicine looking at white matter signal abnormalities in a group of professional fighters.

White matter signal abnormalities are associated with traumatic brain injury. Previous research of MMA athletes did not find greater white matter abnormalities in them compared to control groups.

In this new study, titled Prior football or rugby exposure and white matter signal abnormalities in professional male mixed martial arts fighters, the authors looked at MRI results from 90 active professional MMA fighters and 27 controls.

37 of the fighters had previous football or rugby experience. White matter signal abnormalities were significantly greater in fighters with football/rugby history compared to fighters without football/rugby history. The MMA fighters without football/rugby history.

The full abstract is set out below:

White matter signal abnormalities have been associated with traumatic brain injury (TBI) and repetitive head impacts (RHI) in contact sports (e.g. American football, rugby). However, previous studies of mixed martial arts (MMA) fighters from the Professional Fighters Brain Health Study have not found greater white matter signal abnormalities in fighters versus controls. This study aims to explore the varying white matter effects of football/rugby and MMA by analyzing how football/rugby history in mixed martial arts fighters may relate to white matter signal abnormalities, helping to further our understanding of sport-specific brain health risks. Baseline visits for 90 active, professional, male mixed martial arts fighters and 27 unexposed male controls were cross-sectionally analyzed. Wilcoxon and Kruskal-Wallis tests compared demographics and white matter signal abnormalities, and multivariable regression models examined the associations between football/rugby history and white matter signal abnormality burden in fighters, adjusting for age, education, race, fights, MRI scanner, and supratentorial volume. 37/90 fighters had football/rugby history (mean: 4 years; range: 1-12 years). White matter signal abnormalities were significantly greater in fighters with football/rugby history compared to fighters without football/rugby history (Wilcoxon, p = 0.0190). Football/rugby history was significantly associated with white matter signal abnormality burden > 75th percentile (OR: 12, CI: 3.3-61, p < 0.001) and > 50th percentile (OR: 3.2, CI: 1.2-9.4, p = 0.024) in fighters. Years of football/rugby were also significantly associated with white matter signal abnormalities. Our findings expand on previous literature by demonstrating a significant relationship between white matter signal abnormalities (WMSAs) and football/rugby history but not MMA. Furthermore, our study suggests an added risk for WMSAs in MMA fighters with a history of football/rugby. Future research should further evaluate WMSAs in contact sports, helping to inform athletes, regulatory bodies, and healthcare providers of the potential brain health risks of contact sports.


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