Traumatic brain injury and α-synuclein: Proceed with caution

Abstract

Observational studies strongly suggest that environmental factors contribute to the development of Parkinson disease (PD).(1) These investigations have broadened our understanding of PD pathophysiology, helped guide therapeutic development, and highlighted a road map for prevention.(2) In this context, traumatic brain injury (TBI) is a particularly important risk factor to investigate due to its frequency in the population (estimated at 2.87 million annually) and the potential for reduction through public policy interventions. Results from numerous studies are suggestive but inconsistent, though meta-analyses find significant association of TBI and subsequent development of PD.(3) Far fewer studies have assessed associations with other alpha-synucleinopathies.