Risk of optic neuritis in type 2 diabetes mellitus: A nationwide cohort study

Background/Purpose: This study aimed to investigate the association between the time course of type 2 diabetes mellitus (DM) and the development of optic neuritis (ON) in the Korean population aged 20 years and older. Methods: A total of 10,069,044 subjects were included in this study, which utilized stratified random sampling from the national cohort. The hazard ratios (HRs) for incident ON were compared between subjects with normal fasting glucose (NFG) levels, impaired fasting glucose (IFG) levels, patients with new-onset DM, diabetes duration of fewer than 5 years (early DM), and diabetes duration of 5 years or more (late DM). In addition, the HR for incident ON was assessed and stratified into 20 fasting glucose levels. Results: The cumulative incidence and HR for ON demonstrated a significant increase across the time course of diabetes (adjusted hazard ratio [aHR] = 1.05, 95% confidence interval [CI]: 1.00 to 1.10 for IFG; aHR = 1.31, 95% CI: 1.19 to 1.44 for new-onset DM; aHR = 1.46, 95% CI: 1.32 to 1.60 for early DM; and aHR = 1.92, 95% CI: 1.77 to 2.08 for late DM). Moreover, the HR for ON was 1.71-fold higher in individuals with fasting glucose levels of 132 mg/dL or more compared to those with levels below 75 mg/dL. Conclusion: In this nationwide cohort study, the risk of ON was found to increase with the time course of diabetes and elevated glucose levels. These results suggest that efforts to regulate glucose levels and prevent DM progression could reduce the risk of ON.