“Almost half of equestrian riders (44%) experienced concussions during their careers. Those riders who suffered a brain injury were likely to return to riding without seeking medical clearance. Almost 40% of riders were never educated regarding concussions, while 15% received education from their trainers.”

-Kuhl, Heather N et al. “Concussion history and knowledge base in competitive equestrian athletes.” Sports health vol. 6,2 (2014): 136-8. doi:10.1177/1941738113508073

Here is some data on the correlation between equestrians and brain injuries