Objective: We investigated whether clinically established T1DM is associated with incident PD in a nationwide real-world population.
Background: Recent Mendelian randomization studies have suggested a protective association of genetic liability to T1DM with PD.. However, experimental evidence indicates that insulin deficiency and chronic hyperglycemia may aggravate dopaminergic vulnerability and promote α-synuclein–related pathology.
Method: We conducted a nested case–control study using the Korean National Health Insurance Service database (2010–2022). Incident PD cases were matched to controls by age and sex. Conditional logistic regression was used to estimate adjusted odds ratios (aORs) controlling for vascular and metabolic comorbidities.
Results: A total of 20,293 patients with PD and 81,172 matched controls were included. The mean age was 67.4 years, and 52.7% were female. T1DM was more prevalent among PD cases than controls (0.4% vs. 0.2%, P = 0.002). In conditional logistic regression, T1DM was associated with increased odds of PD (crude OR 1.53, 95% CI 1.16–2.01). This association remained significant after multivariable adjustment (aOR 1.42, 95% CI 1.06–1.90). In duration-stratified analyses, T1DM duration <3 years showed a non-significant increase in PD risk (aOR 1.38, 95% CI 0.83–2.26), whereas T1DM duration ≥3 years was significantly associated with PD (aOR 1.45, 95% CI 1.01–2.08).
Conclusion: In this nationwide population-based nested case–control study, clinically established T1DM was independently associated with increased PD risk. These findings contrast with prior genetic studies suggesting a protective association of T1DM liability with PD and imply that the metabolic burden of sustained insulin deficiency and glycemic dysregulation may outweigh any potentially protective immunogenetic background. Our results support the concept that chronic metabolic stress may contribute to neurodegenerative vulnerability in PD. Further studies incorporating glycemic indices, longitudinal metabolic trajectories, and external cohort validation are warranted.
To cite this abstract in AMA style:
SH. Jeong, MH. Yu, N. Hong. Type 1 Diabetes and Risk of Parkinson’s Disease: A Nationwide Nested Case–Control Study [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/type-1-diabetes-and-risk-of-parkinsons-disease-a-nationwide-nested-case-control-study/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/type-1-diabetes-and-risk-of-parkinsons-disease-a-nationwide-nested-case-control-study/