Relationship between the apolipoprotein E gene and headache following sports-related concussion

Introduction: Headache is one of the most commonly reported and longest lasting symptoms that concussed athletes report, yet the etiology of headache symptoms following concussion is not entirely clear. The purpose of this study was to determine whether the e4 allele of the apolipoprotein E (APOE) gene influences the presence and severity of postconcussion headache. Method: Participants were composed of 45 concussed athletes and 43 healthy/nonconcussed athletes who were involved in a clinically based sports concussion management program. All athletes completed the Post-Concussion Symptom Scale (PCSS). The headache symptom from the PCSS was the primary outcome variable. Buccal samples were collected and analyzed to determine APOE genotype. Results: A significantly greater proportion of concussed e4+ athletes than e4- athletes endorsed headache. Furthermore, concussed e4+ athletes endorsed more severe headaches than e4- athletes. When examining the healthy/nonconcussed sample (i.e., athletes at baseline), results showed no differences between e4 allele groups with respect to the presence and severity of headache. Conclusions: These findings show that when compared to concussed e4- athletes, e4+ athletes are more likely to (a) endorse postconcussion headache and (b) report more severe headache symptoms following concussion. Conversely, it appears that the e4 allele does not influence baseline reports of headache. Thus, results suggest that those with the e4 genotype may be at a higher risk for experiencing headache-related difficulties only after a concussion is sustained.