Diabetic retinopathy is an independent risk factor for ischemic stroke, reported Dr. Ning Cheung of the University of Melbourne's Centre for Eye Research, and associates.
Since retinopathy is a common microvascular manifestation of diabetes, this finding indicates that microvascular disease is an important pathway for stroke in patients with diabetes. In contrast, large-vessel disease plays the central role in ischemic stroke in nondiabetic patients, the researchers said.
They used data from the Atherosclerosis Risk in Communities (ARIC) study to examine the relationship between diabetic retinopathy and ischemic stroke. Two previous population-based studies of the issue were inconclusive, “and few other data are available,” Dr. Cheung and associates noted (Stroke 2007 January [Epub doi:10.1161/01.STR.0000254547.91276.50]).
The ARIC study was a prospective, population-based, cohort study. Subjects were recruited during 1987–1989 and were aged 45–64 years at entry. A subset of 1,617 participants who had retinal photographs taken in the early 1990s accounted for the subjects for Dr. Cheung's study.
After the data were adjusted to account for several potentially confounding factors such as subject age, gender, blood pressure, and smoking status, those who had diabetic retinopathy were significantly more likely to develop ischemic stroke during 7 years of follow-up than were subjects who did not have diabetic retinopathy.
This association remained significant after the data were further adjusted to account for plasma fibrinogen levels and white blood cell count.
There was no dose-dependent association between the severity of retinopathy and the risk of ischemic stroke, the investigators added.