Complex sentence: One large study has estimated the risk of death from bare-knuckle boxing at 14,000 deaths per million participants, which is 184 times more deaths per million participants than for modern professional boxing on 76 deaths per million participants (according to the same study).
Split into simpler sentences: One large study has estimated the risk of death from bare-knuckle boxing at 14,000 deaths per million participants. This is 184 times more deaths per million participants than for modern professional boxing, which has 76 deaths per million participants (according to the same study).