Retinal vein occlusion as an age-dependent marker of incident dementia in a long-term Danish national cohort

Purpose: The aim of this study was to investigate retinal vein occlusion (RVO) as an independent marker of incident dementia.Methods: In a prospective nationwide cohort study, we identified 2 225 568 individuals through the Danish national health registers. Individuals older than 65 years, without unspecified retinal vascular occlusion or dementia were included from 1998 to 2020 and followed until 2022. We calculated the incidence rate (IR) and performed a Cox regression analysis with a hazard ratio (HR) and 95% confidence interval (CI) for RVO (exposure) as a marker of all-cause dementia adjusted for systemic comorbidity.Results: We identified 19 669 individuals with RVO who had a higher prevalence of systemic comorbidity at inclusion compared to those without RVO (n = 2 185 483). We performed a Cox regression analysis for age-dependent exposure due to non-proportional hazards in the pre-planned analysis. Exposed individuals younger than 75 years had an increased risk of all-cause dementia (adjusted HR 1.09, 95% CI 1.01-1.18), whereas individuals older than 75 years had a decreased risk of all-cause dementia (adjusted HR 0.92, 95% CI 0.86-0.98).Conclusion: Individuals with RVO had an age-dependent risk of dementia, with a 9% increased risk in individuals with RVO younger than 75 years and an 8% decreased risk in individuals older than 75 years at the time of exposure.