Background: This study investigated the impact of
metabolic syndrome on the progression from mild parkinsonian signs (MPS) to
Parkinson's disease (PD). Methods: A total of 1,563 participants with MPS completed 6 years of follow-up. The diagnosis of
metabolic syndrome was made according to Adult Treatment Panel III of the National
Cholesterol Education Program. The evaluations of MPS and PD were based on the motor portion of the Unified Parkinson's Disease Rating Scale. Cox proportional hazard models were used to identify the association between
metabolic syndrome and PD conversion. Results: Of the 1,563 participants, 482 (30.8%) with MPS developed PD at the end of the follow-up.
Metabolic syndrome (HR: 1.69, 95% CI: 1.29-2.03) was associated with the risk of PD conversion.
Metabolic syndrome was associated with the progression of
bradykinesia (HR: 1.85, 95% CI: 1.43-2.34), rigidity (HR: 1.36, 95% CI: 1.19-1.57),
tremor (HR: 1.98, 95% CI: 1.73-2.32), and gait/balance impairment (HR: 1.66, 95% CI: 1.25-2.11). The effect of
metabolic syndrome on the progression of
bradykinesia and
tremor was nearly two fold. Participants treated for two or three to four components of
metabolic syndrome, including
high blood pressure, high fasting plasma
glucose,
hypertriglyceridemia, and low HDL-C, had a lower risk of PD conversion. Conclusion:
Metabolic syndrome increased the risk of progression from MPS to PD. Participants treated for two or more components of
metabolic syndrome had a lower risk of PD conversion.