Screening for retinal vessel caliber and its association with metabolic syndrome in Japanese adults.

Background: Retinal microvasculature provides a direct means to assess microvascular health in vivo. We examined whether retinal vessel caliber is associated with the presence of metabolic syndrome in Japanese adults in a health screening program.
Methods: We examined 1,003 Japanese adults through the health screening program conducted at the Shinoda General Hospital. Retinal vessel caliber was measured from digital fundus images using validated, semiautomated computer-assisted software. Metabolic syndrome was defined according to the definition proposed by the Joint Interim Statement in 2009. Cross-sectional associations between retinal vascular caliber and metabolic syndrome or its individual components were determined as odds ratios (ORs) using multiple logistic regression models.
Results: The overall prevalence of metabolic syndrome in the study sample was 29.9%. Persons with increased waist circumference and elevated triglycerides and blood pressure had significantly narrower retinal arterial diameters. Persons with increased waist circumference also had wider retinal venular diameters. Narrower retinal arterial diameters and wider retinal venular diameters were associated with a higher prevalence of metabolic syndrome (OR per -1 standard deviation (SD) change in arteriolar caliber=2.15, 95% confidence interval (CI) 1.45-3.18; OR per +1 SD change in venular caliber=1.53, 95% CI 1.04-2.26).
Conclusions: We observed cross-sectional associations between retinal vessel caliber changes and metabolic syndrome and its components. We demonstrated that retinal vessel caliber assessments are feasible in health screening programs in a timely manner. Further longitudinal studies are warranted to determine whether retinal vessel caliber measurements can be used as noninvasive assessment to evaluate vascular health related to metabolic syndrome and cardiovascular diseases in health screening program.