Globally hypertension is stabilising, but in sub-Saharan Africa the incidence of hypertension remains on an increase. Although this might be attributed to poor healthcare and ineffective antihypertensive treatment, there is a limited understanding of population and individual-specific cardiovascular pathophysiology – necessary for effective prevention and treatment strategies in Africa. As there is a lack of longitudinal studies tracking the early pathophysiological development of hypertension in black populations, the African-PREDICT study was initiated. The purpose of this paper is to describe the detailed methodology and baseline cohort profile of the study. From 2013 to 2017, the study included 1202 black (N = 606) and white (N = 596) men and women (aged 20–30 years) from South Africa – screened to be healthy and clinic normotensive. At baseline, and each 5-year follow-up examination, detailed measures of health behaviours, cardiovascular profile and organ damage are taken. Also, comprehensive biological sampling for the ‘omics’ and biomarkers is performed. Overall, the baseline black and white cohort presented with similar ages, clinic and 24-hour blood pressures, but black adults had lower socioeconomic status and higher central systolic blood pressure than white individuals. The prospective African-PREDICT study in young black and white adults will contribute to a clear understanding of early cardiovascular disease development.

OBJECTIVES Vascular deterioration is suggested to occur earlier in black than white populations, thereby increasing their risk for developing hypertension. To establish whether this is the case, we compared different estimates of arterial stiffness in black and white children and investigated the links with body composition and advanced glycation end products (AGEs) as potential contributors. METHODS We included 40 black and 41 white boys (aged 6-8 years) from similar schools and measured arterial stiffness [pulse wave velocity (PWV) in different arterial sections, systemic arterial compliance and carotid stiffness estimates], anthropometry as well as urinary pentosidine as a marker of AGEs. RESULTS Black boys displayed increased PWV [carotid-to-radial (P = 0.002), carotid-to-femoral (P < 0.0001) and carotid-to-dorsalis pedis (P = 0.008)], DBP (P = 0.001) and carotid intima-media thickness (P = 0.007) than white boys. Despite higher pentosidine in black boys (P = 0.039), arterial stiffness indices did not correlate with pentosidine in any group. However, only in black boys, pentosidine correlated negatively with BMI (P = 0.015), BSA (P = 0.017), weight (P = 0.018), waist (P = 0.022) and hip circumference (P = 0.010). Arterial stiffness indices related inversely to body composition in white boys, but femoral PWV correlated inversely with BMI (r = -0.32; P = 0.049) in black boys. CONCLUSION Already at very young ages (6-8 years), with a high proportion of prehypertension, black boys in our study have increased arterial stiffness in all sections of the arterial tree, along with higher DBP, carotid intima-media thickness and AGEs. This phenotype underlines the increasing trend of early-onset vascular aging among black populations.

This study presents a detailed profile of the renin-angiotensin-aldosterone system (RAAS), electrolytes, volume loading, blood pressure (BP), and total peripheral resistance in healthy young Black and White adults. We also explored longitudinal associations between BP and RAAS. We included normotensive Black (N=543) and White (N=573) adults (20–30 years) and followed N=324 over ≈4.5 years. We measured clinic (central, brachial) and 24-hour BP, total peripheral resistance and left ventricular dimensions. We determined serum NT-proBNP (N-terminal prohormone B-type natriuretic peptide), RAAS, and 24-hour urinary and serum Na ⁺ and K ⁺ . RAAS components, left ventricular internal diameter (diastole), end diastolic volume and NT-proBNP were lower ( P <0.001) in Black than White adults, despite similar clinic SBP. However, central systolic BP and total peripheral resistance were higher in Black adults ( P 0.05) only in quartile 1 of Na ⁺ /K ⁺ values. In both groups, RAAS was lower in the higher quartiles of 24-hour Na ⁺ and NT-proBNP (all P -trend≤0.014). Over 4.5 years, all BPs increased in the Black ( P <0.001) but not White group. The increase in central systolic BP over time was associated with elevated serum aldosterone only in Black adults (β=0.18, P =0.038). We found that RAAS concentrations in healthy Black adults were half of those of White participants, which may not be explained by volume expansion. Yet, baseline aldosterone predicted BP elevation over time in Black adults. RAAS was similar in Black and White adults only at low Na ⁺ /K ⁺ scenarios, suggesting an essential role of potassium. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03292094.

Background: The impact of a sedentary and unhealthy lifestyle on cardiovascular health is well-documented, however the current obesity and hypertension trends among children is concerning. The ExAMIN Youth SA study aims to investigate the impact of lifestyle behaviors (physical fitness/activity, dietary intake and psychosocial factors) involved in early vascular aging among South African children. Methods: This study is an analytical, multidisciplinary, observational cohort study in a school-based setting. We aim to phenotype a cohort of ~1,000 primary school children (black and white boys and girls between ages 5–9 years) based on current clinical childhood conditions including hypertension and obesity. The primary phenotype is large artery stiffness and retinal microvascular diameters, both biomarkers of early vascular aging. The risk factors and mediators of early vascular aging and also responsible for the clinical conditions include physical inactivity, unhealthy diet, and life stress. Additionally, urinalysis and salivary analyses will be performed to identify biomarkers related to the pathophysiology of early vascular aging. Discussion: In line with the growing prevalence of obesity and hypertension responsible for the development of early vascular aging from childhood to adulthood, this study will address the critical areas in which we observe unfavorable arterial modulation related to dietary behaviors, physical inactivity, and early life stress. Implementation of novel biological markers may further contribute to our understanding of early cardiovascular adaptations in childhood, and aid in the development of primary prevention programs. Trial registration: The study was retrospectively registered on ClinicalTrials.gov on 15 August 2019 (NCT04056377).

Context: Extracellular matrix (ECM) remodeling and oxidative stress is present in hypertension and associated arterial stiffness, but little is known on the physiological link among lactate dehydrogenase (LDH), fibulin-1, and reactive oxygen species (ROS). Objective: The objective of this study is to explore the link among a marker of tissue damage (LDH), fibulin-1 (as ECM biomarker), and ROS. Methods: We included 316 black and 305 white South Africans and determined the above-mentioned biomarkers along with additional cardiometabolic risk factors. Results: LDH associated positively with fibulin-1 (β = 0.23; p < 0.001) and ROS (β = 0.11; p = 0.30) in blacks only. Conclusion: Our finding suggests that increased circulating levels of LDH may be due to early ECM remodeling and oxidative stress in blacks that are subjected to detrimental and uncontrolled lifestyle risk factors.