Risk of Parkinson's disease in spinal cord injury: a nationwide cohort study in South Korea.

Despite the association between spinal cord injury (SCI) and various neurological diseases, the risk of Parkinson's disease (PD) in SCI is not elucidated yet. Especially, the role of SCI severity and injury level in the risk of PD development is not investigated. Based on the nation-wide cohort data the Korean National Health Insurance Service between 2010 and 2018, we investigated the incidence of PD in 7,182 patients with SCI compared with 24,844 age- and sex-matched controls. Adjusted hazard ratio and 95% confidence interval (CI) were calculated using Cox proportional hazards regression. We compared the risk of PD based on the degree of disability (without disability, mild, severe) and SCI level (cervical, thoracic, and lumbar). During the mean follow-up duration of 4.31 years, patients with SCI had a higher risk of PD compared with matched controls. The PD risk was greater among patients with SCI with disability than in those without disability, especially those with mild disability. Additionally, cervical-level injury was associated with the highest risk in patients with SCI without disability, while thoracic-level injury was associated with the highest risk in those with disability. Our study found patients with SCI have increased risk of PD, particularly those with disability and thoracic-level injuries.