Increased risk of Parkinson's disease among patients with age-related macular degeneration and visual disability: A nationwide cohort study.

Abstract

The association between Parkinson's disease (PD) and age-related macular degeneration (AMD) has been shown in previous reports. However, the association between the severity of AMD and PD development is unknown. We aimed to evaluate the association of AMD with/without visual disability (VD) with the risk of PD occurrence using the National Health Insurance data in South Korea. A total of 4,205,520 individuals, older than or equal to 50 years and without a previous diagnosis of PD, participated in the Korean National Health Screening Program in 2009. AMD was verified using diagnostic codes, and participants with VD were defined as those with loss of vision or visual field defect as certified by the Korean government. The participants were followed up until 31 December, 2019, and incident cases of PD were identified using registered diagnostic codes. The hazard ratio was calculated for groups (control and AMD with/without visual disability) using multivariable adjusted Cox regression analysis. In total, 37,507 participants (0.89%) were diagnosed with PD. Among individuals with AMD, the risk of PD development was higher in individuals with VD (aHR 1.35, 95% CI 1.09-1.67) than those without (aHR 1.22, 95% CI 1.15-1.30) compared with controls. Additionally, an increased risk of PD was observed in individuals with AMD compared with controls, regardless of the presence of VD (aHR 1.23, 95% CI 1.16-1.31). VD in AMD was associated with the development of PD. This suggests that neurodegeneration in PD and AMD may have common pathways.