Retinal artery occlusion does not act as an independent marker of upcoming dementia: results from a Danish 20-year cohort study

PURPOSE: Retinal artery occlusion (RAO) is a vision threatening disease associated with cerebral vascular dysfunction, which may reflect initial signs of cerebral pathology. Early detection of patients in risk of dementia could allow for preventative treatment. Hence, this study aimed to investigate RAO as an independent biomarker of incident dementia. METHODS: This study was a nationwide, 20-year longitudinal cohort study in Denmark with inclusion from 1998 to 2020 and follow up until the end of 2022. We identified 2 205 159 individuals aged 65 or older through the Danish national health registers and monitored RAO (exposure) and dementia (outcome) status. We calculated incidence rate and performed a Cox regression analysis with hazard ratio (HR) and 95% confidence interval (CI) for RAO as a marker of dementia in a crude, a semi-adjusted (age and sex), and a fully adjusted model (furthermore adjusted for marital status and systemic comorbidity.) RESULTS: We identified 8 863 individuals with RAO. Incidence rates were higher among exposed compared to unexposed individuals (12.28 and 8.18 per 1000 person-years at risk, respectively). Individuals with RAO were more likely to be male and older at inclusion, to have hypertension, dyslipidaemia, cardiovascular disease, chronic kidney disease, and diabetes (p < 0.001). RAO was not associated with all-cause dementia in the crude analysis (HR 1.07 CI [1.00-1.17]) or in the fully adjusted analysis (HR 0.98 CI [0.91–1.06]. CONCLUSION: Although individuals with RAO had a higher incidence of dementia compared to unexposed individuals, these associations were lost when confounders were taken into account. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40942-023-00488-3.