Complete blood cell count and retinal vessel diameters.

OBJECTIVE To examine the cross-sectional associations of components of the complete blood cell count with retinal vessel diameters. METHODS The data are from the baseline examination of the Beaver Dam Eye Study cohort (n = 4730) from March 1, 1988, to September 14, 1990. Blood pressure was measured, a medical history including questions on cigarette smoking was obtained, and fundus photographs centered on the optic disc were taken and digitized. Retinal arteriole and venule diameters were measured using computer-assisted software. The central retinal arteriole equivalent and central retinal venule equivalent were computed. A complete blood cell count was done. RESULTS In age- and sex-adjusted analyses, red blood cell count, hemoglobin level, hematocrit, and white blood cell count were all statistically significantly associated with central retinal venule equivalent and central retinal arteriole equivalent, while platelet count was associated only with central retinal venule equivalent. These relationships persisted in more fully adjusted models, except platelet count became statistically significantly associated with both central retinal arteriole equivalent and central retinal venule equivalent. CONCLUSIONS Blood components as measured in a complete blood cell count are significant correlates of retinal vessel diameters and should be considered in analyses where retinal blood vessel diameters are outcomes.