Could Dopamine Therapy Change the Parkinson Risk Equation?

Researchers explore the link between restless leg syndrome and Parkinson disease.

By
Kathryn Wighton
October 8, 2025
5 min

MDSpire News

Objective:

To examine the association between restless leg syndrome (RLS) and the development of Parkinson disease (PD), and to evaluate the role of dopaminergic pathways.

Approach:

Study Design: A nationwide retrospective cohort study using data from the Korean National Health Insurance Service Sample Cohort from 2002 to 2019.
Participants: 9,919 patients with RLS matched with 9,919 controls by age, sex, income, region, and comorbidity profile.
Analysis: Inverse probability of treatment weighting with stabilized propensity score weights was applied to adjust for demographic, clinical, and lifestyle factors.

Key Findings:

Patients with RLS had a higher incidence of PD (10.1 per 10,000 patient-years) compared to controls (6.3 per 10,000 patient-years).
Among RLS patients, those treated with dopamine agonists (DAs) had a lower incidence of PD (0.5%) compared to those not treated (2%).
During follow-up, 158 patients with RLS developed PD compared with 99 patients in the control group.

Interpretation:

The findings suggest that RLS may be a risk factor for PD rather than an early manifestation, with potential mechanisms involving nondopaminergic pathways.

Limitations:

Diagnostic accuracy may vary due to potential misclassification of rapid eye movement sleep behavior disorder as RLS.
Differentiating idiopathic RLS from secondary RLS based solely on DA treatment may be challenging.