Retinal signs and risk of incident dementia in the Atherosclerosis Risk in Communities study

INTRODUCTION: The easily-imaged retinal microvasculature may reflect the brain microvasculature and therefore be related to dementia. METHODS: In a population-based study of 12,482 adults aged 50-73 years (22% African American), we estimated the relationship of retinal characteristics from fundus photography (1993-1995) with incident all-cause dementia (1993-1995 to 2011-2013) and with etiologic subtype of dementia/mild cognitive impairment (2011-13). RESULTS: A total of 1259 (10%) participants developed dementia over a mean 15.6 years. Moderate/severe (vs. no) retinopathy (hazard ratio [HR], 1.86; 95% confidence interval [CI]: 1.36-2.55) and central retinal arteriolar equivalent (narrowest quartile vs. widest three quartiles; HR, 1.26; 95% CI: 1.09-1.45) were associated with all-cause dementia. Results were qualitatively stronger (but not statistically significantly different) in participants with diabetes. Retinopathy was associated with a joint outcome of cerebrovascular-related, but not Alzheimer's disease-related, dementia/mild cognitive impairment (HR, 2.29; 95% CI: 1.24-4.23). DISCUSSION: Exploration of measures in the eye may provide surrogate indices of microvascular lesions relevant to dementia.