Emerging evidence indicates that repeated heading by soccer players may cause long-term neurological damage. Two new studies of participants in the Einstein Soccer Study suggest that certain genes may be risk factors for microstructural brain changes and cognitive impairment associated with heading.
In the first study, published online on December 11, 2019, in Frontiers in Neurology, the researchers examined 312 adult amateur soccer players enrolled in the Einstein Soccer Study. Participants underwent an MRI technique called diffusion tensor imaging (DTI), which detects microscopic changes to white matter in the brain. They were also tested to see if they carried the gene variant BDNF Val66Met, which impairs the brain’s ability to re-myelinate (i.e., repair damaged nerves) following injury-related brain lesions. In those players who reported a high number of headings over the previous 12 months, DTI findings were consistent with less myelin (a component of healthy neurons) in those players who carried BDNF Val66Met compared with players reporting a low number of headings. The finding suggests that impaired re-myelination (an injury repair mechanism) potentially plays a role in the cognitive dysfunction associated with soccer heading. Screening for the BDNF Val66Met gene variant could be exploited to either identify players at risk or for targeting therapy.
The second study, published online on January 27 in JAMA Neurology, involved 352 Einstein Soccer Study participants. Researchers assessed their soccer-heading frequency over the previous year, their memory function and whether players possessed APOE-ε4—a gene variant known to increase risk for late-stage Alzheimer’s disease and worse outcome after severe traumatic brain injury. Among all players with the APOE-ε4 gene variant, verbal memory was more than four times worse in those players who reported high instances of heading compared with players with low heading exposure over the previous year. The finding suggests that APOE-ε4 is a genetic risk factor for the cognitive impairment associated with high levels of long-term heading. Because the APOE-ε4 gene variant occurs in about 25 percent of the population, the researchers suggest that genetic screening might be useful when assessing individuals for situations where repetitive head trauma is likely, such as collision sports or military combat.
Liane E. Hunter, Ph.D., a MSTP – M.D./Ph.D. student at Einstein, was corresponding author of both papers. Michael L. Lipton, M.D., Ph.D., professor of radiology and of psychiatry and behavioral sciences, associate professor of neuroscience, and associate director of the Gruss Magnetic Resonance Research Center at Einstein, was senior author of both papers.
Posted on: Monday, February 03, 2020