Specifically, we observed elevated serum protein levels of tau and p-tau, as well as shorter telomere length, in comparison to non-collision sport controls.16 Further, we have previously found that male players with a history of concussion exhibited higher levels of serum IL-1β compared with male players without a concussion history, and a positive correlation between IL-18 levels and the number of years of collision sport participation.10 This evidence concerns the gene IL18 and brain injury.