Retinal arteriolar diameter and risk for hypertension

Background: Narrowing of the small arterioles has been hypothesized to contribute to the pathogenesis of hypertension, but prospective clinical data are lacking. Objective: To examine the relation of retinal arteriolar narrowing to incident hypertension in healthy middle-aged persons. Design: Prospective cohort study. Setting: The population-based Atherosclerosis Risk in Communities Study, conducted in 4 U.S. communities. Participants: 5628 persons 49 to 73 years of age without preexisting hypertension. Measurements: Diameters of retinal vessels were measured from digitized retinal photographs. A summary arteriole-to-venule ratio was computed as an indicator of generalized arteriolar narrowing; a lower ratio indicated greater narrowing. Areas of focal arteriolar narrowing were defined from photographs by using a standard protocol. Incident hypertension, defined as systolic blood pressure of 140 mm Hg or higher, diastolic blood pressure of 90 mm Hg or higher, or use of anti hypertensive medication, was identified from the cohort. Results: After 3 years of follow-up, 811 (14.4%) persons had developed hypertension. The incidence of hypertension was higher in persons with lower arteriole-to-venule ratios (incidence of 8.9%, 12.3%, 13.7%, 14.3%, and 22.3%, comparing decreasing quintiles of the ratio) and in persons with focal arteriolar narrowing than in those without focal arteriolar narrowing (25.1% vs. 13.0%). After the authors controlled for the average systolic and diastolic blood pressures over the preceding 6 years, body mass index, waist-to-hip ratio, and other risk factors, the odds of developing hypertension were approximately 60% higher in persons with lower arteriole-to-venule ratios (odds ratio, 1.62 [95% Cl, 1.21 to 2.18] comparing lowest to highest quintile; P = 0.006 for trend) and focal arteriolar narrowing (odds ratio, 1.61 [CI, 1.27 to 2.04]; P < 0.001). Conclusions: smaller retinal arteriolar diameters are independently associated with incident hypertension, which suggests that arteriolar narrowing may be linked to the occurrence and development of hypertension.