Hemostatic cardiovascular risk factors, common carotid-intima medial thickness and peripheral arterial disease in South Asians and African Caribbeans: a substudy to the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study

Abstract

Objective: To determine whether ethnic differences exist in inflammatory (interleukin-6 and C-reactive protein) and hemostatic biomarkers (soluble P-selectin [sP-sel], von Willebrand factor [VWF], and fibrin D-dimer) between South Asian (people originating from India, Pakistan, and Bangladesh) and African Caribbean (Black Caribbean and Black African) groups, the two largest minority ethnic groups in the UK; and to determine associations between these biomarkers and common carotid intima-media thickness and peripheral artery disease (PAD).

Patients and methods: We recruited 572 subjects (356 South Asian and 216 Black) aged ≥ 45 years as a substudy to a community screening project, the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study. All subjects completed an interviewer-led questionnaire, anthropometric measurements were taken, and blood sampling was performed if consent was granted. Ankle brachial pressure index (ABPI) was calculated, and the common carotid intima-media thickness (CCIMT) was measured. PAD was defined as ABPI < 0.9. ELISA was used to quantify inflammatory and hemostatic biomarkers.

Results: The incidence of hypertension (> 70%) and diabetes (> 27%) was high, but non-significantly different between the two ethnic groups. South Asians had higher platelet count and sP-sel levels than African Caribbeans (P < 0.0001 for both), despite there being no significant difference in antiplatelet medication. African Caribbeans had higher D-dimer levels (P = 0.0052). Among South Asians, VWF correlated with ABPI (P = 0.047) and mean (P = 0.002) and maximum CCIMT (P = 0.011) on univariate analysis, and remained an independent predictor of mean and maximum CCIMT on multivariate analysis with traditional cardiovascular risk factors (P = 0.034 and P = 0.046, respectively). In African Caribbeans, D-dimer levels were was higher in PAD than in normal ABPI participants (P = 0.04), and was associated with ABPI in both univariate analysis (P = 0.014) and multivariate analysis (P < 0.0001) with traditional cardiovascular risk factors.

Conclusion: Ethnic differences are evident in inflammatory and hemostatic factors, as well as in their associations with CCIMT and PAD. These may reflect differences in cardiovascular risk factors or pathophysiologic processes that characterize each ethnic group.