Herpes Zoster and Risk of Incident Parkinson’s Disease in US Veterans: A Matched Cohort Study

[[[ Background: ]]] Although some systemic infections are associated with Parkinson’s disease (PD), the relationship between herpes zoster (HZ) and PD is unclear. [[[ Objective: ]]] The objective is to investigate whether HZ is associated with incident PD risk in a matched cohort study using data from the US Department of Veterans Affairs. [[[ Methods: ]]] We compared the risk of PD between individuals with incident HZ matched to up to five individuals without a history of HZ using Cox proportional hazards regression. In sensitivity analyses, we excluded early outcomes. [[[ Results: ]]] Among 198,099 individuals with HZ and 976,660 matched individuals without HZ (median age 67.0 years (interquartile range [IQR 61.4-75.7]); 94% male; median follow-up 4.2 years [IQR 1.9-6.6]), HZ was not associated with an increased risk of incident PD overall (adjusted HR 0.95, 95% CI 0.90-1.01) or in any sensitivity analyses. [[[ Conclusion: ]]] We found no evidence that HZ was associated with increased risk of incident PD in this cohort. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.