Plasma Glutathione and Prodromal Parkinson's Disease Probability

ABSTRACT Background A decrease in glutathione (GSH) levels is considered one of the earliest biochemical changes in Parkinson's disease (PD). Objective The authors explored the potential role of plasma GSH as a risk/susceptibility biomarker for prodromal PD (pPD) by examining its longitudinal associations with pPD probability trajectories. Methods A total of 405 community‐dwelling participants (median age [interquartile range] = 73.2 [7.41] years) without clinical features of parkinsonism were followed for a mean (standard deviation) of 3.0 (0.9) years. Results A 1 μmol/L increase in plasma GSH was associated with 0.4% (95% confidence interval [CI], 0.1%–0.7%; P = 0.017) less increase in pPD probability for 1 year of follow‐up. Compared with participants in the lowest GSH tertile, participants in the highest GSH tertile had a 12.9% (95% CI, 22.4%–2.2%; P = 0.020) slower rate of increase of pPD probability for 1 year of follow‐up. Conclusion Plasma GSH was associated with pPD probability trajectories; therefore, it might assist in the identification of individuals who are likely to reach the threshold for pPD diagnosis more rapidly. © 2021 International Parkinson and Movement Disorder Society