Retinal vascular caliber and metabolic syndrome in a Chinese population

Background: Microvascular changes have been associated with the metabolic syndrome. Methods: We included 869 participants aged >= 40 years from the High-risk for Diabetes Changfeng Study, who had gradable fundus photographs. On digital photographs sum retinal arteriolar and venular calibers were measured with a semi-automated system. Metabolic syndrome was defined according to the International Diabetes Federation consensus. Results: A total of 286 (32.9%) participants was diagnosed with metabolic syndrome. Participants with narrower retinal arteriolar caliber were more often diagnosed with metabolic syndrome (odds ratio 1.78, 95% confidence interval 1.02-3.10; lowest vs highest quintile). Additionally adjusting for age, gender, education, smoking and weekly activity, and adding arteriolar and venular caliber simultaneously in the same models did not alter these associations. In the component analyses, participants with narrower retinal arteriolar caliber were more likely to have central obesity, dyslipidaemia or raised blood pressure, and less likely to have raised fasting plasma glucose. The association between wider venular caliber and metabolic syndrome was less pronounced and non-significant (odds ratio 1.34; 95% confidence interval 0.79-2.38; highest vs lowest quintile). Conclusion: Retinal arteriolar narrowing and, to a lesser extent, retinal venular dilatation were associated with metabolic syndrome in this Chinese population. These vascular changes, although small in magnitude, may still be important in the pathophysiological mechanisms involved in the metabolic syndrome.