Abstract
Background: Recent studies have shown that changes in the retinal microvasculature predict cardiovascular disease (CVD); however, little is known regarding influences on the retinal microvasculature in healthy people without overt cardiovascular or metabolic disease.
Methods: We used a semiautomated computerized technique to analyze digitized retinal photographs from a total of 167 healthy people (age range, 45–75 years; 83 female), without clinical CVD, diabetes, or hypertension, randomly sampled from the population-based Beaver Dam Eye Study. We assessed arteriolar and venular narrowing, arteriolar optimality deviation, and other quantitative aspects of the retinal microvasculature.
Results: Arterioles were significantly narrower and longer, had wider branching angles, and were more tortuous than venules. Increased arteriolar length to diameter ratio (an index of ratio arteriolar narrowing) was positively and independently associated with older age and elevated systolic blood pressure. Arteriolar optimality deviation (an index of microvascular endothelial dysfunction) increased with greater body mass index. Current smoking and increased white blood cell (WBC) count was associated with wider venules. After controlling for smoking, WBC was no longer a significant predictor of venular diameter.
Conclusions: CVD risk factors are associated with retinal microvascular changes in healthy individuals without evidence of CVD, diabetes, or hypertension. CVD risk factors have different influences on the arteriolar and venular bed.
Acknowledgements
The study was supported by a grant from the Wellcome Trust. We are grateful to Stacy Meuer and Karl Jensen for their excellent technical assistance with the study. The Beaver Dam Eye Study was supported by a National Institutes of Health grant (EY06594 to Ronald Klein and Barbara Klein). Professors Chaturvedi, Hughes, and Thom acknowledge the support of the NIHR Biomedical Research Centre Scheme.