Multi center cohort study on association of genotypes with prospective sports concussion: methods, lessons learned, and recommendations.

This was a multicenter prospective cohort study designed to investigate a potential association between genetic polymorphisms of apolipoprotein E gene, apolipoprotein E promoter G219T, and two Tau gene exon 6 polymorphisms (Ser53Pro and Hist47Tyr) with: (1) the risk of prospective concussion, (2) concussion severity, and (3) postconcussion neurocognitive recovery. Almost three thousand student athletes from 26 National Collegiate Athletic Association Division IA, II, III, and National Association of Intercollegiate Athletics academic institutions in the United States met inclusion criteria for this study. We assessed multiple variables including, gender, sport, family history of traumatic brain injury, history of mental illness, history of migraine headache, and baseline and postconcussion neuropsychological test results. Reported concussions were evaluated with multiple instruments including number of symptoms and symptom severity. Additionally, we gathered data via a questionnaire pertaining to medical history, demographics, and sportrelated information, and blood/saliva samples were collected for genetic analysis, and we conducted neuropsychological testing using Headminder and ImPACT software. The goal of this paper is to share our experiences conducting a large prospective cohort study. We recommend that future research include metaanalyses of various traumatic brain injury studies to increase power. Collaborative research is very likely needed given the nature of this study population.