Hemodynamic factors primarily impact on carotid IMT in young adults of African Ancestry in Sub-Saharan Africa

Abstract

Cardiovascular events occur 20 years earlier in Sub-Saharan Africa compared to Europe. The risk factors for atherosclerosis differ between population groups and according to age. We compared the main correlates of carotid intima-media thickness (IMT, an index of atherosclerosis) in young and older adults of African ancestry. Hemodynamic (central and peripheral arterial pressures) and metabolic factors (lipids, glucose, glycated haemoglobin), smoking status and carotid IMT were determined in 573 adult Africans. In young (age<35years, n = 181) and middle-aged (35-59years, n = 231) adults, carotid IMT was associated with hemodynamic and metabolic cardiovascular risk factors on bivariate analyses. In older (age≥60years, n = 161) adults only hemodynamic factors were associated with carotid IMT. After adjustments for confounders, lipids were not associated with carotid IMT at any adult age. Carotid IMT was independently associated with backward wave pressure (Pb, p = 0.001) and age (p = 0.006) in young adults; with hemodynamics (central systolic blood pressure, p = 0.003; Pb, p = 0.02), age (p = 0.0002), body mass index (BMI, p = 0.005) and heart rate (p = 0.007) in middle-aged adults; and with Pb (p < 0.0001), male sex (p = 0.03), and HR (p = 0.04) in older adults. Increased carotid IMT was related to Pb in young (odds ratio [OR] = 1.233, p = 0.0003) and older (OR = 1.086, p = 0.0059) adults, and BMI (OR = 1.089, p = 0.0005) in middle-aged adults. Improvements in predictive performance for detecting increased carotid IMT were shown with Pb in young (p = 0.0032) and older (p = 0.0031) adults, and with BMI (p = 0.0004) in middle-aged adults. In conclusion, in African adults in Sub-Saharan Africa, carotid IMT is associated with hemodynamic factors, but not lipids. Moreover, in young adults, carotid IMT is primarily associated with hemodynamic factors.