Diabetes, Glycated Hemoglobin (HbA1c), and Neuroaxonal Damage in Parkinson's Disease (MARK-PD Study)

BACKGROUND: Diabetes is associated with incidence and prevalence of Parkinson's disease (PD). Furthermore, glycated hemoglobin (HbA1c) levels have been linked with motor function and progression.

OBJECTIVES: We evaluated the relationship between prevalent diabetes and HbA1c levels with serum neurofilament light chain (NfL) levels as marker of neuroaxonal damage.

METHODS: NfL concentrations were analyzed with Simoa in serum of 195 PD patients with available HbA1c values. Motor (MDS-UPDRS III, Hoehn & Yahr [H&Y]) and cognitive (Montreal Cognitive Assessment [MoCA]) function was assessed and vascular comorbidities were documented from medical records.

RESULTS: PD patients with prevalent diabetes had higher serum NfL levels and lower MoCA scores independent of age, body mass index (BMI), and vascular risk factors. Furthermore, diabetes was associated with higher H&Y stages in unadjusted and age/BMI-adjusted models. Higher HbA1c levels were associated with increased NfL in unadjusted and age/BMI-adjusted models.

CONCLUSIONS: In PD patients, diabetes and high HbA1c are associated with increased neuroaxonal damage and cognitive impairment. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson Movement Disorder Society.