Comparison of the retinal microvasculature in European and African-Caribbean people with diabetes

Abstract

Diabetes aggravates the impact of elevated BP (blood pressure) on the microcirculation, and people of African ancestry with diabetes are more susceptible to microvascular damage than Europeans. In the present study, we investigated possible differences in the retinal microcirculation in people of European and African-Caribbean ethnicity with diabetes that might account for this. A total of 51 subjects with Type 2 diabetes (age 40–65 years; 25 male; 29 African-Caribbean) were studied. Clinic and 24 h ambulatory BP, and fasting glucose, insulin and lipids were measured. Digital retinal images were analysed using custom-written semi-automatic software to determine: LDR (length/diameter ratio) and AVR (arteriolar/venular diameter ratio), branching angles, vessel tortuosity and NT (number of terminal vessel branches). Arterioles were narrower in European people with diabetes than in African-Caribbean people with diabetes [mean (S.D.) arteriolar diameter, 76 (7) compared with 82 (11) μm respectively (P=0.03); arteriolar LDR, 28.1 (8.5) compared with 23.7 (7.0) respectively (P=0.046); and AVR, 0.66 (0.21) compared with 0.90 (0.36) respectively (P=0.028)]. Ethnic differences in arteriolar LDR, arteriolar diameter and AVR were not explained by differences in BP, but were attenuated by adjustment for the duration of diabetes. There was no significant relationship between BP and arteriolar narrowing in the group as a whole, although the relationship between arteriolar LDR and systolic BP was stronger in Europeans than African-Caribbeans [β=0.08 (0.07) compared with β=0.03 (0.06); P=0.03]. In conclusion, in the presence of diabetes, a relationship between BP and retinal arteriolar diameter was not evident and implies impaired small artery remodelling in the presence of diabetes. African-Caribbean people with diabetes have wider retinal arterioles and this could contribute to enhanced microvascular damage in this ethnic group.

Microcirculatory Rarefaction in South Asians — A Potential Mechanism for Increased Cardiovascular Risk and Diabetes

“…This was explained by their higher blood pressure, but it was also noted that diabetes influenced the relationship between blood pressure and arteriolar diameter. This is consistent with the findings of Mahal et al [35] who reported wider arteriolar calibre in African Caribbean people with diabetes than Europeans with diabetes. Similar observations showing an interaction between arteriolar calibre, diabetes and ethnicity have also been reported in MESA.…”

Early Signs of End‐Organ Damage in Retinal Arterioles in Patients with Type 2 Diabetes Compared to Hypertensive Patients

“…Disease duration has been previously shown to influence retinal arteriolar/venular diameter ratio in diabetic patients . Our observation that WT as well as CA, both parameters of hypertrophic remodeling, are related to diabetes duration indicates “disease duration” as an impact factor of retinal microvascular changes.…”

Socio‐economic and ethnic inequalities in diabetes retinal screening

“…However, these differences were not independent of obesity, duration of diabetes and diabetes treatment and control [20]. Some recent studies have examined the retinal microvasculature directly [21–23], leading to suggestions that there may be increased susceptibility to microvascular damage in African Caribbeans [22].…”