Retinal microvascular abnormalities and risks of incident stroke and its subtypes: The Circulatory Risk in Communities Study

Background: This study aimed to investigate the association between retinal microvascular abnormalities and the risk of incident stroke and its subtypes in the general Japanese population.

Methods: A total of 12 965 residents aged 40-74 years without a history of stroke and/or coronary heart disease underwent retinal photography during the annual health checkups of four Japanese communities between 1990 and 1999. Retinal microvascular abnormalities, such as the presence or absence of generalized arteriolar narrowing, focal arteriolar narrowing, arteriovenous nicking, enhanced arteriolar light reflex, and retinal hemorrhages were graded using standard protocols.

Results: During a median follow-up of 20 years, 817 patients were diagnosed with incident stroke. Retinal microvascular abnormalities were positively associated with the risk of total stroke; after adjustment for age, sex, community, SBP, antihypertensive medication use, and other cardiovascular risk factors, the multivariable hazard ratio [95% confidence interval (CI)] was 1.68 (1.42-1.98), 1.67 (1.34-2.07), 1.41 (1.17-1.72), 1.54 (1.26-1.87), and 1.57 (1.19-2.07) for generalized arteriolar narrowing, focal arteriolar narrowing, arteriovenous nicking, enhanced arteriolar light reflex, and retinal hemorrhages, respectively. Similar positive associations were observed for the risk of stroke subtypes, except for subarachnoid hemorrhage, for which no association was observed. Furthermore, the positive associations were similar in participants with and without hypertension.

Conclusion: Retinal microvascular abnormalities were positively associated with the risk of incident stroke in the general Japanese population. Routine retinal photography could provide positive clinical insights into stroke risk stratification independent of blood pressure, antihypertensive medication use, and other risk factors.