Abstract
Emerging evidence from terrestrial cohorts suggests that ionizing radiation (IR) exposure may increase the risk of Parkinson’s disease (PD). Understanding the biological mechanisms underlying IR-induced PD is therefore critical for assessing health risks, particularly in the context of long-duration missions to the Moon and Mars. This perspective explores mechanistic pathways that may support causal links between IR and PD and highlights experimental and epidemiological approaches relevant for strengthening causal inference.