Age-related macular degeneration and dementia: Association through pathogenesis or visual impairment?

Background Studies suggest a link between blindness, age-related macular degeneration (AMD), and dementia risk, but whether this stems from AMD pathology or blindness remains unclear. This study examines the relationship between AMD and dementia. Objective To evaluate the association between AMD and 5-year dementia risk in non-blind patients. Methods This retrospective cohort study used TriNetX to compare non-blind patients with exudative AMD (n = 35,021) and non-exudative AMD (n = 96,809) to those without AMD (n = 1,801,879) for five-year dementia risk. Blind (n = 90,615) and non-blind (n = 800,737) patients were compared. Cohorts were propensity-matched for confounding factors. Results Non-blind AMD patients had decreased Alzheimer's disease risk, while blindness showed a strong positive association. Exudative AMD had HR of 0.84 (95% CI = 0.72, 0.97), non-exudative AMD had HR of 0.95 (95% CI = 0.87, 1.04), but blindness increased Alzheimer's disease risk (95% HR = 1.29, CI = 1.17, 1.41). Conclusions These findings suggest that previously reported associations between AMD and dementia may be partially mediated by visual impairment. The modest reduction in dementia risk in non-blind AMD patients may reflect differences in healthcare utilization or treatment exposure among AMD patients.