Determinants of retinal venular diameter: the Beaver Dam Eye Study


OBJECTIVE: To describe how retinal venular diameter changes over time for an individual and to examine differences in these changes among people with different risk profiles. DESIGN: Population-based cohort study. PARTICIPANTS: A total of 4600 persons aged 43 to 86 years from the Beaver Dam Eye Study (BDES) who participated in at least 1 examination and had venular diameter measured in the right eye. METHODS: Data from 4 examinations during a 15-year period were analyzed. Retinal venular diameter was measured from photographs at each examination by computer-assisted methods and summarized as the central retinal venular equivalent (CRVE). Associations of risk factors with concurrent CRVE measurements and changes in CRVE over time were determined using multivariate analyses. MAIN OUTCOME MEASURES: Central retinal venular equivalent. RESULTS: The CRVE tended to narrow with age. Mean CRVE was approximately 5 μm smaller (225 vs. 230 μm) for the average 70-year-old compared with the average 50-year-old, and was approximately 13 μm smaller (217 vs. 230 μm) for the average 85-year-old compared with the average 50-year-old. Male sex (beta estimate [β] = 5.24; 95% confidence interval [CI], 3.58-6.90), history of current cigarette smoking (β = 9.38; 95% CI, 8.26-10.49), and higher white blood cell (WBC) count (per 1000/μL: β = 0.95; 95% CI, 0.74-1.16) were independently associated with larger concurrent CRVE, whereas higher mean arterial blood pressure (per 5 mmHg: β = -0.36; 95% CI, -0.50 to -0.23) and higher serum high-density lipoprotein (HDL) cholesterol (per 10 mg/dl: β = 0.89; 95% CI, -1.15 to -0.63) were independently associated with smaller concurrent CRVE. History of cardiovascular disease (CVD) (β = -0.16; 95% CI, -0.26 to -0.06) and presence of chronic kidney disease (CKD) (β = -0.20; 95% CI, -0.34 to -0.05) were associated with a greater decrease in CRVE over time. CONCLUSIONS: These data show that retinal venular diameter tends to narrow with age; concurrent venular diameter is independently associated with sex, blood pressure, serum HDL cholesterol, WBC count, and history of current cigarette smoking; and change in CRVE is independently associated with a history of CVD and presence of CKD. The different independent effects of these interrelated factors on CRVE highlight the complex relationship between CRVE and systemic diseases and conditions and the difficulty in determining specific causes of change in CRVE over time.