Early vascular changes are suggested to develop prematurely in the black population even in
the absence of vascular disease, therefore increasing their risk for hypertension and arterial
stiffness development. Different factors are known to contribute to the development of arterial
stiffness, including biological ageing, adiposity and advanced glycation end-products (AGEs).
AGEs are formed through non-enzymatic oxidation and glycation of free amino acid groups of
lipids, nucleic acids and proteins. Formation of AGEs is stimulated by hyperglycemia and is
associated with conditions such as diabetes mellitus. AGEs have received scientific interest
regarding their role in arterial stiffness and cardiovascular related diseases such as type 2
diabetes mellitus. Information regarding the influence of AGEs on arterial stiffness in children is
scant, and no previous comparative studies regarding the contribution of body composition and
AGEs on arterial stiffness development in black and white children have been conducted.
To compare different estimates of arterial stiffness in 6–8 year old black and white South African
boys and investigate the links between arterial stiffness indices, body composition and
advanced glycation end-products (AGEs).
We included 40 black and 41 white South African boys aged from 6–8 years in this study. This
study obtained approval from the Provincial Department of Education and the Health Research
Ethics Committee of the North-West University (NWU-00007-15-A1). We excluded obese
children and those using any chronic medication, with type 1 diabetes mellitus, renal disease or
cancer. AGEs, specifically pentosidine, in urine was analysed by a trained biochemist. Trained
postgraduate students measured blood pressure in triplicate and continuous arterial blood
pressure with participants in a sitting position. The SonoSite MicroMaxx (SonoSite Micromaxx,
Bothell, WA) and a 6-13 MHz linear array probe were used to determine the carotid artery
distensibility. Pulse wave velocity (PWV) was determined across various sections (carotidradial;
carotid-dorsalis pedis; carotid-femoral) of the arterial tree in duplicate. Anthropometric
measurements included body height, weight, hip, waist and neck circumferences and were
measured in triplicate. Body mass index z-scores were used to classify body composition of the
boys according to appropriate age, height and weight cut-offs.
Age and body composition were comparable between the groups except for white boys with
higher neck circumference (p=0.003) and waist-to-hip ratio (p<0.0001) than black boys.
Pentosidine levels were higher in black boys (p=0.039), as well as diastolic blood pressure
(p=0.001), mean arterial pressure (p=0.003) and total peripheral resistance (p=0.044) compared
to white boys. After adjusting for mean arterial pressure, carotid-to-radial pulse wave velocity,
carotid-to-femoral pulse wave velocity and carotid-to-dorsalis pedis pulse wave velocity (all
p<0.002) as well as carotid intima-media thickness (p=0.007) were higher in black compared to
white boys. Correlations between measures of arterial stiffness and body composition were
evident in white boys only. Carotid-to-femoral PWV correlated inversely with BMI (r =–0.32;
p=0.049), only in black boys. Pentosidine inversely correlated with body composition variables
including body mass index (p=0.015), body surface area (p=0.017), weight (p=0.018), waist
circumference (p=0.022) and hip circumference (p=0.010) in black boys only. Arterial stiffness
indices did not correlate with AGEs in any group.
General conclusion :
In conclusion, pulse wave velocity of black boys was higher in all sections of the arterial tree,
along with higher diastolic blood pressure, intima-media thickness and AGEs, suggesting that
early arterial changes are already present in young black boys. This phenotype may have an
impact on the increasing trend of hypertension in the black population of South Africa.