Association between glycemic status and the risk of Parkinson disease: A nationwide population-based study

Objective: Previous studies have suggested that diabetes mellitus (DM) increases the risk of Parkinson disease (PD); however, this has not been conclusively established. We analyzed the risk of PD based on baseline glucose tolerance status in a large-scale cohort representative of the general Korean population.

Research Design and Methods: This analysis was performed in a cohort of 15,168,021 adults aged ≥40 years who underwent health checkups under the National Health Insurance Service between January 2009 and December 2010. The clinical course of subjects was followed until December 2016. Subjects were classified into the following groups: non-diabetes (non-DM), impaired fasting glucose (IFG), DM duration <5 years, and DM duration ≥5 years. We analyzed the adjusted hazard ratio of PD for each group.

Results: During the observation period of 49,076,148.74 person-years, PD occurred in 31,577 patients. Compared with the non-DM subjects, the adjusted hazard ratio was 1.038 (95% confidence interval [CI], 1.009–1.067) in the IFG group, 1.185 (95% CI, 1.143–1.229) in the DM duration <5 years group, and 1.618 (95% CI, 1.566–1.672) in the DM duration ≥5 years group. These results were consistent with those of the subgroup analysis, and the presence of DM further increased the risk of PD regardless of comorbidities such as cardiovascular, cerebrovascular, and chronic kidney diseases.

Conclusion: This population-based cohort study suggests that DM is an independent risk factor for PD.