GFAP Levels May Identify Risk for Brain Atrophy, Cognitive Decline in Athletes

Among professional fighters exposed to repetitive head impacts, the use of plasma glial fibrillary acidic protein (GFAP) may help identify those who are at risk for progressive regional brain atrophy and cognitive decline, according to study findings published in Alzheimer’s Research & Therapy.

Researchers conducted a longitudinal cohort study in active and retired boxers and mixed martial artists (MMA) sourced via The Professional Athletes Brain Health study (PABHS) and reported on the links between baseline biomarkers, mental function, volume changes assessed via magnetic resonance imaging (MRI) in participants continually exposed to repeated head injury (RHI) over time.

The researchers evaluated the following parameters: MRI regional volumes, plasma levels of neurofilament light chain (NfL), GFAP, p-tau231, and N-terminal tau (NTA). They also performed several statistical analyses to assess the relationship between plasma levels and regional brain volumes and cognitive performance at baseline and longitudinally. The researchers looked at mental function via central nervous system (CNS) Vital Signs, which encompassed areas including verbal memory, symbol, digit coding, Stroop, and finger tapping test.

The researchers analyzed data from 140 active boxers (mean age, 31); 211 active MMA fighters (mean age, 30); 69 retired boxers (mean age, 49); and 52 control participants (mean age, 36).

Retired boxers exhibited the highest baseline GFAP levels (retired boxers vs active MMA: P =.0191), whereas active boxers had higher levels of NfL (active boxers vs MMA: P =.047).

Additionally, plasma p-tau231 was found to be elevated in active MMA fighters as opposed to retired boxers (P =.026) and control participants (P =.0166).

Over time, retired boxers with higher levels of GFAP showed reduced volumes in multiple brain structures (hippocampus: beta = -1.25; 95% CI, -1.65 to -0.85) and larger lateral ventricles (beta = 1.75; 95% CI, 1.46 to 2.04). 

Moreover, as GFAP levels increased, cognitive performance in various domains, including memory, processing speed, psychomotor speed, and reaction time decreased (eg, processing speed: beta = 0.04; 95% CI, 0.07 to 0.02; reaction time: beta = 0.52; 95% CI, 0.28 to 0.76).

Higher levels of GFAP in active fighters were found to be associated with reduced volumes of the thalamus (beta = -1.42; 95% CI, -2.34 to -0.49) and corpus callosum. These findings were further linked to declining scores in psychomotor speed (beta = 0.14; 95% CI, 0.01-0.27).

The findings of the study may be limited due to its longitudinal design and the non-random sampling of professional fighters in the PABHS.

“Further longitudinal studies over greater amounts of time and with different cohorts exposed to RHI are needed to verify our findings,” the researchers concluded.

Disclosure: Several study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.