ORCID Profile
0000-0001-7680-2032
Current Organisations
North-West University
,
Southern African Hypertension Society (SAHS)
,
Childhood Hypertension Consortium of South Africa (CHCSA)
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Publisher: Oxford University Press (OUP)
Date: 08-2020
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.NUMECD.2014.02.005
Abstract: Simple, low-cost central obesity measures may help identify in iduals with increased cardiometabolic disease risk, although it is unclear which measures perform best in African adults. We aimed to: 1) cross-sectionally compare the accuracy of existing waist-to-height ratio (WHtR) and waist circumference (WC) thresholds to identify in iduals with hypertension, pre-diabetes, or dyslipidaemia 2) identify optimal WC and WHtR thresholds to detect CVD risk in this African population and 3) assess which measure best predicts 5-year CVD risk. Black South Africans (577 men, 942 women, aged >30years) were recruited by random household selection from four North West Province communities. Demographic and anthropometric measures were taken. Recommended diagnostic thresholds (WC > 80 cm for women, >94 cm for men WHtR > 0.5) were evaluated to predict blood pressure, fasting blood glucose, lipids, and glycated haemoglobin measured at baseline and 5 year follow up. Women were significantly more overweight than men at baseline (mean body mass index (BMI) women 27.3 ± 7.4 kg/m(2), men 20.9 ± 4.3 kg/m(2)) median WC women 81.9 cm (interquartile range 61-103), men 74.7 cm (63-87 cm), all P 0.5 appears to be more consistently supported and may provide a better predictor of future cardiometabolic risk in sub-Saharan Africa.
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.ATHEROSCLEROSIS.2013.12.025
Abstract: Insulin-like growth factor-1 (IGF-1) has potent endothelial-protective, anti-platelet and anti-thrombotic activities, and also exerts mitogenic and proliferatory actions on vascular smooth muscle cells. Conflicting reports exist regarding the role of IGF-1 in vascular protection and atherogenesis. We therefore investigated the relationships of ambulatory blood pressure (BP) and carotid intima-media thickness (cIMT) with a range of components of the IGF-1 axis in a bi-ethnic population. We included black (N = 86) and white (N = 101) men and measured growth hormone, total IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3), and pregnancy-associated plasma protein-A (PAPP-A) levels. Ambulatory BP was almost 10 mmHg higher in black men (137/88 mmHg versus 128/80 mmHg both p < 0.001), accompanied by an adverse profile of the IGF-axis for all measured components (all p < 0.01), including reduced bioavailable IGF-1 (IGF-1/IGFBP-3 p = 0.006) and tissue IGF-1 accessibility index as represented by IGF-1.PAPP-A/IGFBP-3 (p < 0.001). Single, partial and multiple regression analyses confirmed an independent inverse association between ambulatory systolic BP and bioavailable IGF-1 in black men (R(2) = 0.24 β = -0.22 p = 0.035). cIMT was similar in the ethnic groups (p = 0.34), and was negatively associated with bioavailable IGF-1 in white men (R(2) = 0.42 β = -0.17 p = 0.039) prior to adjustment for γ-glutamyl transferase (R(2) = 0.45 β = -0.10 p = 0.25). Ambulatory systolic BP is inversely related to bioavailable IGF-1 in black men who displayed low IGF-1 concentrations. An inverse relation was found between cIMT and IGF-1 in white men, which disappeared after correction for γ-glutamyl transferase - opposing reports of a detrimental role of IGF-1 in the early stages of atherogenesis.
Publisher: MDPI AG
Date: 25-04-2022
DOI: 10.3390/JCDD9050130
Abstract: This study aims to compare soluble (pro)renin receptor [s(P)RR] levels between black and white adults and to explore the associations of left ventricular (LV) structure and function with s(P)RR in the total and ethnicity-stratified groups. The study s le included 1172 apparently healthy black (n = 587) and white (n = 585) participants of the African-PREDICT study aged 20–30 years. Echocardiography was performed to determine relative wall thickness (RWT), LV mass index, LV ejection fraction and stroke volume index (SVi). s(P)RR was analyzed from serum s les, while plasma renin activity-surrogate (PRA-S) and eq angiotensin II were determined using the RAS™ Fingerprint. s(P)RR was higher in the white participants compared to the black participants (p 0.001). In multivariable-adjusted linear regression analyses, we observed a positive association between RWT and s(P)RR (β = 0.141 p = 0.005) and negative associations of LV ejection fraction (β = −0.123 p = 0.016) and SVi (β = −0.144 p = 0.004) with s(P)RR only in white adults. Higher s(P)RR observed in white vs. black participants was associated with higher RWT and poorer LV function only in young white adults but not in their black counterparts. These results suggest that s(P)RR may contribute to LV remodeling and dysfunction in white populations due to its role in volume–pressure regulation and its proinflammatory as well as profibrotic effects.
Publisher: Springer Science and Business Media LLC
Date: 29-03-2023
DOI: 10.1007/S11306-023-01987-Y
Abstract: Increased exposure to risk factors in the young and healthy contributes to arterial changes, which may be accompanied by an altered metabolism. To increase our understanding of early metabolic alterations and how they associate with markers of arterial stiffness, we profiled urinary metabolites in young adults with cardiovascular disease (CVD) risk factor(s) and in a control group without CVD risk factors. We included healthy black and white women and men ( N = 1202), aged 20–30 years with a detailed CVD risk factor profile, reflecting obesity, physical inactivity, smoking, excessive alcohol intake, masked hypertension, hyperglycemia, dyslipidemia and low socio-economic status, forming the CVD risk group ( N = 1036) and the control group ( N = 166). Markers of arterial stiffness, central systolic blood pressure (BP) and pulse wave velocity were measured. A targeted metabolomics approach was followed by measuring amino acids and acylcarnitines using a liquid chromatography-tandem mass spectrometry method. In the CVD risk group, central systolic BP (adjusted for age, sex, ethnicity) was negatively associated with histidine, arginine, asparagine, serine, glutamine, dimethylglycine, threonine, GABA, proline, methionine, pyroglutamic acid, aspartic acid, glutamic acid, branched chain amino acids (BCAAs) and butyrylcarnitine (all P ≤ 0.048). In the same group, pulse wave velocity (adjusted for age, sex, ethnicity, mean arterial pressure) was negatively associated with histidine, lysine, threonine, 2-aminoadipic acid, BCAAs and aromatic amino acids (AAAs) (all P ≤ 0.044). In the control group, central systolic BP was negatively associated with pyroglutamic acid, glutamic acid and dodecanoylcarnitine (all P ≤ 0.033). In a group with increased CVD risk, markers of arterial stiffness were negatively associated with metabolites related to AAA and BCAA as well as energy metabolism and oxidative stress. Our findings may suggest that metabolic adaptations may be at play in response to increased CVD risk to maintain cardiovascular integrity.
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.IJCARD.2018.11.116
Abstract: Due to the known contribution of excess sodium intake on elevations in blood pressure, salt reduction regulations are being introduced in countries all over the world. To study the contribution of sodium intake on cardiovascular disease development, we determined whether left ventricular mass associates with sodium excretion in young adults free from overt cardiovascular disease and those with masked hypertension. We included 681 participants (41% men and 50% black) in a cross-sectional analysis from the African-PREDICT study with complete 24-hour urine collections and successful ambulatory blood pressure monitoring (>70% valid readings). The participants were categorized as normotensive (n = 534) or masked hypertensive (n = 147). In addition, we determined left ventricular mass index (LVMI) along with traditional risk factors. Masked hypertensive in iduals had higher sodium excretion (149 vs. 128 mmol/L/day) and LVMI (78.1 vs. 69.6 g/m Our results indicated that higher sodium excretion (reflecting a higher salt intake) may contribute to increased left ventricular mass, potentially driven by the early development of masked or undetected hypertension.
Publisher: Oxford University Press (OUP)
Date: 28-07-2016
Abstract: Inconsistent findings are reported on whether insulin-like growth factor-1 (IGF-1) is protective or harmful in predicting hypertension, carotid wall thickness and mortality. We determined the five-year prognostic value of IGF-1 for these outcomes in a large Black population prone to hypertension and cardiovascular disease. A longitudinal study as part of the PURE (Prospective Urban and Rural Epidemiology) study, North West Province, South Africa. We measured IGF-1 and IGF binding protein-3 (IGFBP-3) in 1038 HIV-uninfected participants (age range 32-94 years) and assessed blood pressure, carotid intima-media thickness and mortality. Over five years 116 deaths occurred. Baseline IGF-1 was similar in survivors and non-survivors (p = 0.50), but tended to be higher in survivors upon adjustment for IGFBP-3 and covariates (p = 0.061). Normotensives and hypertensives (p = 0.072), and those with carotid intima-media thickness < 0.9 mm and ≥ 0.9 mm also displayed similar baseline IGF-1 (p = 0.55). Multivariable-adjusted Cox-regression indicated high IGF-1 predicting lower risk for all-cause mortality (hazard ratio 0.45 0.23-0.88) and cardiovascular mortality (hazard ratio 0.26 0.08-0.83) when also adjusting for IGFBP-3. When including normo- and hypertensives at baseline, high IGF-1 was related to normotension at follow-up (hazard ratio 0.68 0.49-0.95). We found no association with carotid intima-media thickness (hazard ratio 0.59 0.31-1.14). In a Black South African population with low socio-economic status and harmful health behaviours, we found a protective independent association between IGF-1 and hypertension, cardiovascular and all-cause mortality, with no association with carotid wall thickness.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2021
DOI: 10.1161/HYPERTENSIONAHA.120.16879
Abstract: 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 .001) in Black than White adults, despite similar clinic SBP. However, central systolic BP and total peripheral resistance were higher in Black adults ( P .001). Plasma renin activity and angiotensin II were comparable between Black and White groups ( P .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 .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. URL: www.clinicaltrials.gov Unique identifier: NCT03292094.
Publisher: Elsevier BV
Date: 04-2021
DOI: 10.1016/J.NUMECD.2020.12.021
Abstract: Heart rate variability (HRV) is a main determinant of autonomic function and related to the development of hypertension and cardiovascular (CV) disease. Hypertension develops in black populations at an earlier age, which could be due to differences in the autonomic nervous system activity and sodium otassium handling in black and white populations. We investigated whether HRV is associated with 24 h urinary sodium and potassium excretion and blood pressure (BP) in a young bi-ethnic cohort. We examined 423 black and 483 white healthy adults (aged 24.5 ± 3.1 years) for 24 h HRV, including standard deviation of normal RR intervals (SDNN) reflecting autonomic variations over time, and root mean square of successive differences (RMSSD) reflecting parasympathetic activity. We measured 24 h urinary sodium and potassium concentration and BP. The black group had lower SDNN and potassium excretion as well as higher RMSSD, sodium and Na/k ratio compared to the white group (all p < 0.05). Only in black in iduals, urinary potassium excretion was independently and negatively associated with SDNN (β[95% CI] -0.26[-0.50 -0.02]ms) and RMSSD (-0.14[-0.27 -0.01]ms, p < 0.05). One unit increase in sodium otassium (Na/K) ratio was associated with higher SDNN (β[95% CI] 3.04[0.89 5.19]ms) and RMSSD (1.60[0.41 2.78]ms) in the black cohort only (both p < 0.001). In both groups elevated 24 h diastolic BP was associated with lower RMSSD (p < 0.05). Lower potassium excretion and higher Na/K ratio related independently to higher HRV in young and healthy black adults. A better ethnic-specific understanding of sodium and potassium handling is required as part of preventive cardiology, especially in black in iduals. ClinicalTrials.gov Identifier: NCT03292094 URL: t2/show/NCT03292094.
Publisher: Springer Science and Business Media LLC
Date: 17-11-2022
DOI: 10.1038/S41440-022-01097-7
Abstract: Cardiovascular disease (CVD) affects in iduals across the lifespan, with multiple cardiovascular (CV) risk factors increasingly present in young populations. The underlying mechanisms in early cardiovascular disease development are complex and still poorly understood. We therefore employed urinary proteomics as a novel approach to gain better insight into early CVD-related molecular pathways based on a CVD risk stratification approach. This study included 964 apparently healthy (no self-reported chronic illnesses, free from clinical symptoms of CVD) black and white men and women (aged 20-30 years old) from the African Prospective study on the Early Detection and Identification of Cardiovascular disease and Hypertension (African-PREDICT) study. Cardiovascular risk factors used for stratification included obesity, physical inactivity, tobacco use, high alcohol intake, hyperglycemia, dyslipidemia and hypertension. Participants were ided into low (0 risk factors), medium (1-2 risk factors) and high (≥3 risk factors) CV risk groups. We analyzed urinary peptidomics by capillary electrophoresis time-of-flight mass spectrometry. After adjusting for ethnicity, sex and age, 65 sequenced urinary peptides were differentially expressed between the CV risk groups (all q-values ≤ 0.01). These peptides included a lower abundance of collagen type I- and III-derived peptides in the high compared to the low CV risk group. With regard to noncollagen peptides, we found a lower abundance of alpha-1-antitrypsin fragments in the high compared to the low CV risk group (all q-values ≤ 0.01). Our findings indicate lower abundances of collagen types I and III in the high compared to the low CV risk group, suggesting potential early alterations in the CV extracellular matrix.
Publisher: Springer Science and Business Media LLC
Date: 22-08-2017
DOI: 10.1007/S00726-017-2483-5
Abstract: The relationship of both asymmetric (ADMA) and symmetric (SDMA) dimethylarginine with carotid wall thickness is inconclusive especially among black populations. We aimed to compare carotid intima media thickness (cIMT) and dimethylarginine levels in 75 black and 91 white men at baseline and after a 3-year follow-up, and to investigate associations of percentage change in cIMT with percentage change in dimethylarginine levels (ADMA and SDMA). Plasma levels of ADMA and SDMA were determined with a liquid chromatography mass spectrometry method and B-mode ultrasonography was used to determine the cIMT at baseline and follow-up. In black men, mean cIMT (p = 0.79) and ADMA levels (p = 0.67) remained the same, but SDMA levels were lower (p < 0.001) when comparing baseline and follow-up. In white men, cIMT increased (p < 0.001), but both mean ADMA and SDMA levels decreased (p < 0.001) over time. In black men, percentage change in cIMT was positively associated with percentage change in ADMA (R
Publisher: Springer Science and Business Media LLC
Date: 19-11-2019
DOI: 10.1038/S41371-018-0121-7
Abstract: In the article "Morning blood pressure surge in young black and white adults: The African-PREDICT Study" by Gontse Gratitude Mokwatsi, Aletta Elisabeth Schutte, Catharina Martha Cornelia Mels and Ruan Kruger which appeared in 'Journal of Human Hypertension' (2018) volume 32, DOI 10.1038/s41371-018-0089-3, the authors regret that they mentioned erroneously that none of their study participants had an exaggerated morning blood pressure surge. They would like to point out that 40 participants in their study population had an exaggerated sleep-trough surge whereas 128 had an exaggerated dynamic surge.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
Publisher: Springer Science and Business Media LLC
Date: 22-03-2021
DOI: 10.1038/S41366-021-00803-8
Abstract: Circulating growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine that increases in older in iduals with established cardiovascular disease (CVD) and obesity. To address potential targets in primary prevention, we aimed to determine whether body weight, waist circumference, waist/height ratio, body mass index (BMI), body surface area (BSA) and leptin associate with GDF-15 in young underweight, lean and overweight/obese (ow/ob) adults. We included 1189 adults aged 20-30 years. We grouped participants as underweight (BMI ≤ 18 kg/m Our findings may suggest that in young adults with either underweight or excess adiposity, increased GDF-15 levels may contribute to the development of future cardiovascular health risks associated with pro-inflammation.
Publisher: Springer Science and Business Media LLC
Date: 17-07-2020
DOI: 10.1038/S41440-020-0514-1
Abstract: Hypertension is common in black populations and is known to be associated with low nitric oxide (NO) bioavailability. We compared plasma and urinary NO-related markers and plasma creatine kinase (CK) levels between young healthy black and white adults along with the associations of these markers with the urinary albumin-to-creatinine ratio (uACR), which is a surrogate marker of endothelial and kidney function. We included 1105 participants (20-30 years). We measured the uACR, plasma CK, plasma and urinary arginine, homoarginine, asymmetric (ADMA) and symmetric dimethylarginine (SDMA), urinary ornithine/citrulline, nitrate and nitrite, and malondialdehyde (MDA). In addition, the urinary nitrate-to-nitrite ratio (U
Publisher: Springer Science and Business Media LLC
Date: 27-01-2011
DOI: 10.1038/JHH.2010.134
Abstract: Many mechanisms, including oxidative stress, contribute to hypertension. This study investigated the possible associations between oxidative stress, blood pressure and arterial stiffness in black South Africans. Ambulatory blood pressure measurements were taken for 101 black South African men and 99 women. The stiffness indices included ambulatory arterial stiffness index (AASI) and pulse pressure (PP). Reactive oxygen species (ROS) levels (P<0.0001) were higher in the African women compared with men. ROS levels were also higher in hypertensive compared with normotensive men. The 24 h systolic blood pressure (SBP P<0.01), 24 h diastolic blood pressure (DBP P<0.0001) and pulse wave velocity (PWV P<0.01) were significantly higher in African men compared with women. There were unadjusted positive associations of 24 h SBP (r=0.33 P=0.001), 24 h DBP (r=0.26 P=0.008) and 24 h PP (r=0.29 P=0.003) with ROS in African men only. A positive association between AASI and ROS existed only in hypertensive men (r=0.27 P=0.035), but became nonsignificant (B=0.0014 P=0.14) after adjustments. Adjusted, positive associations of 24 h SBP (B=0.181 P=0.018) and 24 h PP (B=0.086 P=0.050) with ROS were again only evident in African men. ROS is positively associated with SBP and PP in African men, suggesting that increased ROS levels may contribute to hypertension in this population group.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2016
Publisher: Informa UK Limited
Date: 03-12-2015
Publisher: Elsevier BV
Date: 02-2019
Publisher: Oxford University Press (OUP)
Date: 10-02-2014
DOI: 10.1093/AJH/HPT288
Abstract: Increased urinary albumin excretion reflects general vascular damage and predicts adverse cardiovascular and renal outcomes. Albuminuria can be determined from easily collected spot urine s les, especially in low-resource settings. However, no prognostic evidence exists for Africans. We followed clinical outcomes in 1,061 randomly selected non diabetic, human immunodeficiency virus (HIV)-negative Africans (mean age: 51.5 years 62.0% women). Baseline urinary albumin-to-creatinine ratio was assessed from spot urine s les. Over a median follow-up of 4.52 years, 132 deaths occurred, of which 47 were cardiovascular related. The urinary albumin-to-creatinine ratio averaged 6.1 μg/mg (5th to 95th percentile interval 1.2-70.0). In multivariable-adjusted analyses, urinary albumin excretion predicted all-cause mortality (hazard ratio (HR), 1.26 95% confidence interval (CI), 1.07-1.48 P = 0.006), and a tendency existed for cardiovascular mortality (HR, 1.26 95% CI, 0.97-1.63 P = 0.087), which seemed to be driven by fatal stroke (HR, 1.72 95% CI, 1.17-2.54 P = 0.006) rather than cardiac mortality (HR, 0.67 95% CI, 0.41-1.07 P = 0.094). The predictive value remained in 528 hypertensives for both all-cause (HR, 1.38 95% CI, 1.13-1.69 P = 0.001) and cardiovascular (HR, 1.45 95% CI, 1.07-1.96 P = 0.017) mortality, again driven by stroke. Our findings also remained significant after we excluded participants with macroalbuminuria, those on antihypertensive treatment, as well as participants who died within 1 year after enrollment. In nondiabetic HIV-negative Africans, albuminuria predicts all-cause and stroke mortality.
Publisher: Wiley
Date: 13-07-2020
DOI: 10.1111/ECI.13330
Publisher: Springer Science and Business Media LLC
Date: 04-08-2018
DOI: 10.1007/S00394-018-1800-4
Abstract: In the Original publication of the article Fig. 1 was published incorrectly. The correct figure is given below. The original article has been corrected.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.HLC.2016.11.010
Abstract: Hypertensive heart disease is a rising concern, especially among black South African women. As high sensitivity cardiac troponin T (cTnT) is a marker of cardiomyocyte damage, we determined the potential link of (i) systemic endothelial dysfunction (reflected by urinary albumin-to-creatinine ratio), (ii) large artery stiffness, (iii) cardiac volume load (estimated by the N-terminal prohormone B-type natriuretic peptide (Nt-proBNP)), and (iv) ECG left ventricular hypertrophy in post-menopausal black women. In 121 (50 normotensive and 71 hypertensive) black women (mean age: 60.6 years), basic cardiovascular assessments including blood pressure and ECG were performed, along with plasma and urinary biomarkers including cTnT. The cTnT levels (p=0.049) along with Nt-proBNP (p=0.003), pulse pressure (p<0.0001) and the Cornell product (p=0.030) were higher in hypertensive than normotensive women. Only in hypertensive women, was cTnT independently associated with urinary albumin-to-creatinine ratio (β=0.25 p=0.019), pulse pressure (β=0.31 p=0.019), Nt-proBNP (β=0.47 p<0.0001) and Cornell product (β=0.31 p=0.018). An independent association between albumin-to-creatinine ratio and cTnT was also evident in normotensive women (β=0.34 p=0.037). We found cTnT to be a useful marker in an elderly black population relating to several measures of cardiovascular deterioration - from subclinical endothelial dysfunction to left ventricular hypertrophy.
Publisher: Georg Thieme Verlag KG
Date: 08-10-2014
Abstract: Severe underweight may be a risk factor for hypertension in developing countries, although the manner whereby this occurs is unknown. Leptin is known to exert both beneficial and detrimental vascular effects, and is predictive of poor cardiovascular outcome at high levels, but also at low levels. We explored the relationship between blood pressure and leptin in black men from South Africa with a body mass index (BMI) in the underweight to normal range. We included 113 African men (BMI≤25 kg/m(2)) and took anthropometric, biochemical and cardiovascular measures. The blood pressure-leptin relationship was then investigated along quintiles of leptin and within BMI stratified median split (20 kg/m(2)) groups. Blood pressure increased across leptin quintiles 1-3 (p for trend≤0.040), whereas no relationship was observed along quintiles 3 to 5 (p for trend≥0.14) (adjusted for age and waist circumference). Blood pressure was similar in the two BMI median split groups (p≥0.083). In the low BMI group only, blood pressure associated positively with leptin following unadjusted, partial, and full adjustment (systolic blood pressure and diastolic blood pressure: R(2)=0.20-0.27, β=0.32-0.34, p≤0.009). Decreasing leptin levels are not likely to contribute to hypertension prevalence in the underweight. Rather, in African men with a BMI≤20 kg/m(2), low leptin levels are positively and independently associated with elevated blood pressure, which is not seen at higher BMI (20-25 kg/m(2)). Our findings suggest a differential concentration dependent vascular effect of leptin in underweight and normal weight African men.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.HLC.2018.07.003
Abstract: It is well established that an exaggerated morning blood pressure surge (MBPS) is associated with an increased risk for cardiovascular disease development in hypertensive in iduals. However, in non-dipping in iduals, a lower surge was reportedly associated with increased cardiovascular risk. Sympathetic nervous system activity is involved in 24-hour blood pressure fluctuations, including night-time dipping and the MBPS. To better understand this interaction, we investigated associations of MBPS with heart-rate variability and baroreceptor sensitivity in young healthy dippers and non-dippers. We included black and white men and women (n=827), aged 20-30 years and determined the MBPS using two formulas: the sleep-trough and dynamic morning surge. For autonomic function we determined baroreceptor sensitivity and heart-rate variability. The majority of non-dippers in this population were black (70.4%), presenting lower sleep-trough and dynamic morning surge (all p<0.001). Heart-rate variability was comparable between dippers and non-dippers, whereas baroreceptor sensitivity was higher in non-dippers (p=0.021). Despite a suppressed MBPS profile in non-dippers, we found both sleep-trough (β=-0.25 p=0.039) and dynamic morning surge (β=-0.14 p=0.047) to be inversely and independently associated with 24-hour heart-rate variability (total power). These results were absent in dippers. In conclusion, we found a higher night-time blood pressure coupled with lower MBPS in young healthy non-dippers. Furthermore, this lower MBPS was independently and negatively associated with autonomic neural activity, suggesting increased autonomic function involvement in MBPS suppression of non-dippers. The predictive value of suppressed nocturnal dipping pattern should be investigated while taking autonomic neural activity into account.
Publisher: MDPI AG
Date: 18-10-2020
DOI: 10.3390/NU12103185
Abstract: The endogenous Na+/K+-ATPase inhibitor, marinobufagenin (MBG), strongly associates with salt intake and a greater left ventricular mass index (LVMi) in humans and was shown to promote cardiac fibrosis and hypertrophy in animals. The adverse effects of MBG on cardiac remodeling may be exacerbated with obesity, due to an increased sensitivity of Na+/K+-ATPase to MBG. This study determined whether MBG is related to the change in LVMi over time in adults with a body mass index (BMI) ≥30 kg/m2 (obese) and kg/m2 (non-obese). The study followed 275 healthy participants (aged 20–30 years) from the African-Prospective study on the Early Detection and Identification of Cardiovascular disease and Hypertension (African-PREDICT) study over 4.5 years. At baseline, we measured 24 h urine MBG excretion. MBG levels were positively associated with salt intake. LVMi was determined by two-dimensional echocardiography at baseline and after .5 years. With multivariate adjusted analyses in obese adults (N = 56), we found a positive association of follow-up LVMi (Adjusted (Adj.) R2 = 0.35 Std. β = 0.311 p = 0.007) and percentage change in LVMi (Adj. R2 = 0.40 Std. β = 0.336 p = 0.003) with baseline MBG excretion. No association of LVMi (Adj. R2 = 0.37 p = 0.85) or percentage change in LVMi (Adj. R2 = 0.19 p = 0.68) with MBG excretion was evident in normal weight adults (N = 123). These findings suggest that obese adults may be more sensitive to the adverse cardiac effects of MBG and provide new insight into the potential role of dietary salt, by way of MBG, in the pathogenesis of cardiac remodeling in obese in iduals.
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.JASH.2014.12.003
Abstract: Evidence of the relationship between left ventricular hypertrophy and urinary albumin excretion is contradictory and limited in black adults in whom hypertensive heart disease is common. We aimed to investigate the relationship between subclinical left ventricular hypertrophy and albuminuria in non-diabetic hypertensive blacks. Urinary albumin-to-creatinine ratio (UACR) was determined from 8-hour overnight urine collection. We recorded ambulatory blood pressure and 12-lead electrocardiogram during a typical working day. Cornell product (P = .002), UACR (P = .042), 24-hour systolic pressure (P < .0001), and 24-hour pulse pressure (P < .0001) were higher in the hypertensive group. Cornell product was associated with UACR in single (r = 0.25 P = .012), partial (P trend = .002), and multiple regression (β = 0.326 P = .0005) analyses in the hypertensive group only, even below the threshold for microalbuminuria and independent of 24-hour systolic pressure. Urinary albumin excretion is associated with subclinical left ventricular hypertrophy in non-diabetic hypertensive blacks and may be a useful marker of early cardiovascular disease in blacks.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2018
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2017
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.IJCARD.2017.08.070
Abstract: Pulse pressure lification (PPA), i.e. the lification from central arteries to the periphery, is inversely related to arterial stiffness, organ damage and mortality. It is known that arterial stiffness is higher in black than white populations, but it is unclear if this is due to early vascular aging. We therefore investigated whether PPA declines earlier in young normotensive black South Africans, when compared to their white counterparts. We included 875 black and white men and women from the African-PREDICT study (55% black, 41% men), aged 20-30years, with no prior diagnosis of chronic disease, screened for normotensive clinic blood pressure (BP). We determined supine central PP (cPP), and supine brachial systolic- and diastolic BP, from which brachial PP (bPP) was calculated. PPA was defined as the ratio of the litude of the PP between these distal and proximal locations (bPP/cPP). We found the mean PPA to be lower in black compared to white participants (1.43 vs. 1.46 P=0.013). In black adults PPA declined earlier with increasing age (P-trend<0.001), with a weak trend in whites (P=0.069) after adjustment for sex, socio-economic status, height, heart rate and mean arterial pressure. In multivariable-adjusted regression, we found an independent inverse association between PPA and age only in the black group (β=-0.18, P=0.002). PPA declines earlier with age in normotensive black adults younger than 30years, exemplifying early vascular aging which may predispose black in iduals to future cardiovascular outcomes.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Wiley
Date: 03-04-2023
Abstract: Hypertension is one of the most important and complex risk factors for cardiovascular diseases (CVDs). By using urinary peptidomics analyses, we aimed to identify peptides associated with hypertension, building a framework for future research towards improved prediction and prevention of premature development of CVD. We included 78 hypertensive and 79 normotensive participants from the African‐PREDICT study (aged 20–30 years), matched for sex (51% male) and ethnicity (49% black and 51% white). Urinary peptidomics data were acquired using capillary‐electrophoresis‐time‐of‐flight‐mass‐spectrometry. Hypertension‐associated peptides were identified and combined into a support vector machine‐based multidimensional classifier. When comparing the peptide data between the normotensive and hypertensive groups, 129 peptides were nominally differentially abundant (Wilcoxon p 0.05). Nonetheless, only three peptides, all derived from collagen alpha‐1(III), remained significantly different after rigorous adjustments for multiple comparisons. The 37 most significant peptides (all p ≤ 0.001) served as basis for the development of a classifier, with 20 peptides being combined into a unifying score, resulting in an AUC of 0.85 in the ROC analysis ( p 0.001), with 83% sensitivity at 80% specificity. Our study suggests potential value of urinary peptides in the classification of hypertension, which could enable earlier diagnosis and better understanding of the pathophysiology of hypertension and premature cardiovascular disease development.
Publisher: Public Library of Science (PLoS)
Date: 13-03-2013
Publisher: Informa UK Limited
Date: 02-09-2014
DOI: 10.3109/10715762.2014.951840
Abstract: Various studies indicate a relationship between increased oxidative stress and hypertension, resulting in increased DNA damage and consequent excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG). The aim of this study was to compare urinary 8-oxodG levels in African and Caucasian men and to investigate the association between ambulatory blood pressure (BP) and pulse pressure (PP) with 8-oxodG in these groups. We included 98 African and 92 Caucasian men in the study and determined their ambulatory BP and PP. Biochemical analyses included, urinary 8-oxodG, reactive oxygen species (ROS) (measured as serum peroxides), ferric reducing antioxidant power (FRAP), total glutathione (GSH), glutathione peroxidase (GPx) and glutathione reductase (GR) activity. The African men had significantly higher systolic (SBP) and diastolic blood pressure (DBP) (both p < 0.001). Assessment of the oxidative stress markers indicated significantly lower 8-oxodG levels (p < 0.001) in the African group. The African men also had significantly higher ROS (p = 0.002) with concomitant lower FRAP (p < 0.001), while their GSH levels (p = 0.013) and GR activity (p < 0.001) were significantly higher. Single and partial regression analyses indicated a negative association between urinary 8-oxodG levels with SBP, DBP and PP only in African men. These associations were confirmed in multiple regression analyses (SBP: R(2) = 0.41 β = -0.25 p = 0.002, DBP: R(2) = 0.30 β = -0.21 p = 0.022, PP: R(2) = 0.30 β = -0.19 p = 0.03). Our results revealed significantly lower urinary 8-oxodG in African men, accompanied by a negative association with BP and PP. We propose that this may indicate a dose-response relationship in which increased oxidative stress may play a central role in the up-regulation of antioxidant defence and DNA repair mechanisms.
Publisher: Elsevier BV
Date: 08-2023
Publisher: Oxford University Press (OUP)
Date: 05-2019
Abstract: Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global c aign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 c aign was expanded, aiming to include more participants and countries. Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic s ling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 in iduals (mean age 45.3 years 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) in iduals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 in iduals with untreated hypertension and 111 214 in iduals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension. May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The c aign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these in iduals at risk.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2020
DOI: 10.1161/HYPERTENSIONAHA.120.14874
Abstract: Elevated blood pressure remains the single biggest risk factor contributing to the global burden of disease and mortality. May Measurement Month is an annual global screening c aign aiming to improve awareness of blood pressure at the in idual and population level. Adults (≥18 years) recruited through opportunistic s ling were screened at sites in 92 countries during May 2019. Ideally, 3 blood pressure readings were measured for each participant, and data on lifestyle factors and comorbidities were collected. Hypertension was defined as a systolic blood pressure ≥140 mm Hg, or a diastolic blood pressure ≥90 mm Hg (mean of the second and third readings) or taking antihypertensive medication. When necessary, multiple imputation was used to estimate participants’ mean blood pressure. Mixed-effects models were used to evaluate associations between blood pressure and participant characteristics. Of 1 508 130 screenees 482 273 (32.0%) had never had a blood pressure measurement before and 513 337 (34.0%) had hypertension, of whom 58.7% were aware, and 54.7% were on antihypertensive medication. Of those on medication, 57.8% were controlled to /90 mm Hg, and 28.9% to /80 mm Hg. Of all those with hypertension, 31.7% were controlled to /90 mm Hg, and 350 825 (23.3%) participants had untreated or inadequately treated hypertension. Of those taking antihypertensive medication, half were taking only a single drug, and 25% reported using aspirin inappropriately. This survey is the largest ever synchronized and standardized contemporary compilation of global blood pressure data. This c aign is needed as a temporary substitute for systematic blood pressure screening in many countries worldwide.
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.HLC.2011.10.009
Abstract: This study compared NT-proBNP levels and the association with cardiovascular markers between Africans and Caucasians from South Africa. This cross-sectional study involved 201 Africans and 255 Caucasians from the North West province, South Africa. Serum NT-proBNP concentrations, blood pressure, pulse wave velocity and arterial compliance were measured. NT-proBNP levels were significantly higher (P<0.001) in Africans than Caucasians, also after adjusting for gender, body mass index (BMI) and pulse wave velocity (P=0.008). This significant difference became borderline significant after adjusting for systolic blood pressure (SBP) (P=0.060), and non-significant after adjusting for arterial compliance (P=0.35). In single regression, a significant positive correlation of NT-proBNP with SBP (r=0.26 P<0.001) and pulse pressure (PP) (r=0.28 P<0.001) were shown for Africans only. After multiple adjustments, the associations of NT-proBNP with SBP and PP remained significant in Africans (SBP: β=0.187, P<0.01 PP: β=0.234, P<0.001), with no significant associations in Caucasians. NT-proBNP levels were higher in Africans than Caucasians, independently of BMI and gender. This difference was partly driven by higher SBP and lower arterial compliance in Africans. NT-proBNP was persistently associated with SBP and PP in Africans, but not in Caucasians. These associations may suggest early vascular changes contributing to cardiac alterations in Africans.
Publisher: MDPI AG
Date: 20-03-2020
DOI: 10.3390/JCM9030844
Abstract: Proteinic arginine dimethylation (PADiMe) is a major post-translational modification. Proteolysis of asymmetric and symmetric PADiMe products releases asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), respectively, two endogenous atherogenic substances. SDMA, ADMA, and its major metabolite dimethylamine (DMA) are eliminated by the kidney. The urinary concentrations of DMA+ADMA, SDMA, and DMA+ADMA+SDMA are useful measures of the whole-body asymmetric and symmetric PADiMe, respectively. Urinary (DMA+ADMA)/SDMA is an index of the asymmetric to symmetric PADiMe balance. In two bi-ethnic studies, the ASOS (39 black boys, 41 white boys) and the African-PREDICT (292 black young men, 281 white young men) studies, we investigated whether ethnicity is a major determinant of PADiMe, and whether PADiMe is associated with blood pressure and ethnicity-dependent growth and inflammatory factors, including HDL. DMA, ADMA, and SDMA were measured in spot urine s les by gas chromatography–mass spectrometry, and their excretion was corrected for creatinine excretion. In black boys, creatinine-corrected DMA, DMA+ADMA, and DMA+ADMA+SDMA concentrations were lower by 11.7%, 9.5%, and 7.6% (all p 0.05), respectively, compared to the white boys, and 3.4%, 2.0%, and 1.8% lower (all p 0.05), respectively, in black compared to white men. (DMA+ADMA)/SDMA did not differ between black boys and black men, but was higher in white boys compared to white men. ADMA did not differ between black and white boys, or between black and white men. Creatinine-corrected SDMA excretion was lower in black boys compared to white boys (by 8%) and to white men (by 3.1%). None of the PADiMe indices were associated with blood pressure in either study. IGF-binding protein 3 correlated inversely with all PADiMe indices in the black men only. Our study showed that asymmetric proteinic arginine dimethylation is higher in white boys than in black boys, and that this difference disappears in adulthood. ADMA metabolism and SDMA excretion were lower in the black subjects compared to the white subjects, suggesting ethnicity-dependent hepatic and renal elimination of ADMA and SDMA in the childhood. The results of our study may have clinical relevance beyond atherosclerosis, such as in growth and inflammation, which have not been sufficiently addressed thus far.
Publisher: Springer Science and Business Media LLC
Date: 21-07-2018
DOI: 10.1007/S00394-018-1791-1
Abstract: There is global consensus on the benefits of reducing excessive salt intake. Indeed, lower salt intake associates with reduced arterial stiffness, a well-established predictor of cardiovascular risk, in older populations. Whether high habitual salt intake in healthy normotensive youth may already contribute to increased arterial stiffness is unknown. We, therefore, determined whether estimated salt intake is associated with large artery stiffness in young healthy black and white adults. We included 693 black and white adults (51% black 42% men), aged 20-30 years. Participants were normotensive based on clinic blood pressure, and no previous diagnosed chronic illnesses. We measured carotid femoral pulse wave velocity (cfPWV) and determined estimated salt intake based on 24 h urinary sodium excretion. We found estimated salt consumption of > 5 g/day in 47% of our population, whereas 21% consumed > 10 g/day. In multivariable-adjusted regression analyses a positive association existed between estimated salt intake and cfPWV in the total group (Adj. R Excessive salt intake is positively associated with large artery stiffness-independent of blood pressure-in young adults, especially in black in iduals. Our results suggest a potential contributory role of salt consumption towards early vascular aging.
Publisher: Wiley
Date: 08-06-2021
DOI: 10.1111/MICC.12714
Abstract: Lifestyle risk factors vary between socioeconomic status (SES) groups and may influence cardiovascular function differently. The retinal microvasculature allows for monitoring early changes in cardiovascular health, and therefore, we investigated whether retinal vessel calibers associate differently with modifiable risk factors in different SES groups. We included 1064 young adults (aged 20–30 years) grouped by low and high SES. The central retinal artery and vein equivalents (CRAE, CRVE) were determined from fundus images captured using the Dynamic Retinal Vessel Analyzer (Imedos Systems GmbH, Jena, Germany). We collected anthropometry, self‐reported alcohol consumption, and biochemical data. Retinal vessel calibers did not differ between SES groups ( p ≥ .80) after adjusting for sex and ethnicity. Unique independent associations were observed in the low SES group, where CRAE ( β = 0.08, p = .042) and CRVE ( β = .14, p = .001) associated positively with cotinine and body mass index, respectively. In the high SES group, CRAE ( β = –0.09, p = .027) associated negatively with alcohol consumption. At young ages, retinal vessel calibers associated differently with modifiable lifestyle risk factors within each SES group. Our data highlight the importance of detecting adverse lifestyle risk factors among young adults from erse socioeconomic settings to improve prevention of cardiovascular disease.
Publisher: Springer Science and Business Media LLC
Date: 23-07-2019
DOI: 10.1038/S41371-018-0089-3
Abstract: An exaggerated morning blood pressure surge (MBPS) has independent predictive value for cardiovascular mortality and is suggested to be prevalent in elderly hypertensive patients: men and white populations. To better understand the MBPS profile in a young and normotensive population, we evaluated the MBPS in young adults and explored associations with demographic, cardiovascular and health behaviour measurements. We included 845 black (n = 439) and white (n = 406) men and women aged between 20 and 30 years. We calculated the sleep-trough and dynamic morning surge, and compared demographic data, health behaviours and ambulatory blood pressure according to MBPS quartiles. In the total group, higher waist circumference, socioeconomic score, lean mass, ambulatory blood pressure (24-h, daytime blood pressure) and increased night-time dipping (all p < 0.05) were found in the highest sleep-trough and dynamic morning surge quartiles. In the total white group, particularly men, both sleep-trough and dynamic morning surge were higher than the black group (all p < 0.013). More black participants were non-dippers than whites (44% vs 34% p = 0.004). In multivariable adjusted regression in the total group, we found no consistent associations of MBPS with demographic and health behaviour measurements. MBPS related independently and positively with night-time percentage dipping in all ethnic groups (all p < 0.01). Ethnic differences in MBPS is evident in young adults, with a higher, but normal MBPS in white men. A non-dipping night-time pattern in young black adults (with reduced MBPS) and a higher MBPS (observed in dippers) may serve as potential risk factors for cardiovascular disease.
Publisher: Springer Science and Business Media LLC
Date: 03-12-2020
DOI: 10.1038/S41371-020-00453-9
Abstract: Lower nitric oxide (NO) bioavailabilty associates with hypertension in patients and elderly populations. With hypertension known to develop earlier in black populations, we compared both plasma and urinary NO-related markers and their associations with central systolic blood pressure (cSBP) and arterial stiffness in healthy young black and white adults. We included healthy black and white men and women (n = 1110 20-30 years) and measured cSBP and pulse wave velocity (PWV), along with both plasma and urinary arginine, homoarginine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), as well as urinary ornithine/citrulline, nitrite and nitrate. In addition, the urinary nitrate-to-nitrite ratio (U
Publisher: Springer Science and Business Media LLC
Date: 23-03-2017
DOI: 10.1038/JHH.2017.18
Abstract: Consistent reports indicate that hypertension is a particularly common finding in black populations. Hypertension occurs at younger ages and is often more severe in terms of blood pressure levels and organ damage than in whites, resulting in a higher incidence of cardiovascular disease and mortality. This review provides an outline of recent advances in the pathophysiological understanding of blood pressure elevation and the consequences thereof in black populations in Africa. This is set against the backdrop of populations undergoing demanding and rapid demographic transition, where infection with the human immunodeficiency virus predominates, and where under and over-nutrition coexist. Collectively, recent findings from Africa illustrate an increased lifetime risk to hypertension from foetal life onwards. From young ages black populations display early endothelial dysfunction, increased vascular tone and reactivity, microvascular structural adaptions as well as increased aortic stiffness resulting in elevated central and brachial blood pressures during the day and night, when compared to whites. Together with knowledge on the contributions of sympathetic activation and abnormal renal sodium handling, these pathophysiological adaptations result in subclinical and clinical organ damage at younger ages. This overall enhanced understanding on the determinants of blood pressure elevation in blacks encourages (a) novel approaches to assess and manage hypertension in Africa better, (b) further scientific discovery to develop more effective prevention and treatment strategies and
Publisher: Oxford University Press (OUP)
Date: 08-2020
DOI: 10.1093/EURHEARTJ/SUAA043
Abstract: Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. May Measurement Month (MMM) is a global initiative of the International Society of Hypertension (ISH) aimed at raising awareness of high BP and acting as a temporary solution to the lack of screening programmes worldwide. As part of MMM, screening in South Africa in 2017 revealed that 24.5% of adults (mean age = 31 years) have hypertension and only half of those with hypertension had controlled BP. These data highlight the need for continued screening and awareness c aigns. An opportunistic cross-sectional survey of volunteers aged ≥18 years was carried out in May 2018. Blood pressure measurements, the definition of hypertension and statistical analyses followed the MMM protocol. The sites screened were general populations and university c uses in preference to hospitals and clinics, aiming to raise awareness and allow access to screening to those less likely to be aware of their BP. In total, 2965 in iduals (age 40.5 ± 18.2 years) were screened. After multiple imputation for missing BP readings, 34.6% had hypertension, only 56.7% of those with hypertension were aware, 21.2% of those not receiving treatment for hypertension were hypertensive, and a large proportion (42.5%) of in iduals receiving antihypertensive medication had uncontrolled BP. These results suggest that opportunistic screening c aigns can identify significant numbers with undiagnosed and uncontrolled hypertension. The high proportions of in iduals with undiagnosed and treated uncontrolled hypertension highlight the need for hypertension awareness c aigns and more rigorous management of hypertension.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2015
Publisher: Springer Science and Business Media LLC
Date: 14-10-2022
DOI: 10.1038/S41440-022-01071-3
Abstract: In Black populations excessive salt intake may exacerbate the genetic predisposition to hypertension and promote the early onset of cardiovascular disease. Ethnic differences in the interaction between sodium intake and the metabolome may play a part in hypertension and cardiovascular disease development. We determined (1) urinary amino acid and acylcarnitine profiles of young Black and White adults according to low, moderate, and high dietary salt intake, and (2) investigated the triad of salt intake, systolic blood pressure (SBP), and the associated metabolomics profile. This study included 447 White and 380 Black adults aged 20-30 years from the African-PREDICT study. Estimated salt intake was determined from 24-hour urinary sodium levels. Urinary amino acids and acylcarnitines were measured using liquid chromatography-tandem mass spectrometry. Black adults exhibited no significant differences in SBP, amino acids, or acylcarnitines across low ( 10g/day) salt intake. White adults with a high salt intake had elevated SBP compared to those with low or moderate intakes (p < 0.001). Furthermore, gamma-aminobutyric acid (GABA) (q = 0.020), citrulline (q = 0.020), glutamic acid (q = 0.046), serine (q = 0.054) and proline (q = 0.054) were lowest in those with higher salt intake. Only in White and not Black adults did we observe inverse associations of clinic SBP with GABA (Adj. R
Publisher: Oxford University Press (OUP)
Date: 11-07-2018
Abstract: The endogenous steroidal inhibitor of sodium–potassium-dependent adenosine triphosphate and natriuretic hormone, marinobufagenin, plays a physiological role in ionic homeostasis. Animal models suggest that elevated marinobufagenin adversely associates with cardiac and renal, structural and functional alterations. It remains uncertain whether marinobufagenin relates to the early stages of target organ damage development, especially in young adults without cardiovascular disease. We therefore explored whether elevated 24-hour urinary marinobufagenin excretion was related to indices of subclinical target organ damage in young healthy adults. This cross-sectional study included 711 participants from the African-PREDICT study (black 51%, men 42%, 24.8 ± 3.02 years). We assessed cardiac geometry and function by two-dimensional echocardiography and pulse wave Doppler imaging. 24-Hour urinary marinobufagenin and sodium excretion were measured, and the estimated glomerular filtration rate determined. Across marinobufagenin excretion quartiles, left ventricular mass ( P 0.001), end diastolic volume ( P 0.001), stroke volume ( P = 0.004) and sodium excretion ( P 0.001) were higher within the fourth compared with the first quartile. Partial regression analyses indicated that left ventricular mass ( r = 0.08, P = 0.043), end diastolic volume ( r = 0.10, P = 0.010) and stroke volume ( r = 0.09, P = 0.022) were positively related to marinobufagenin excretion. In multivariate-adjusted regression analysis, left ventricular mass associated positively with marinobufagenin excretion only in the highest marinobufagenin excretion quartile (adjusted R 2 = 0.20 β = 0.15 P = 0.043). This relationship between left ventricular mass and marinobufagenin excretion was evident in women (adjusted R 2 = 0.06 β = 0.127 P = 0.015) but not in men (adjusted R 2 = 0.06 β = 0.007 P = 0.92). Left ventricular mass positively and independently associates with marinobufagenin excretion in young healthy adults with excessively high marinobufagenin excretion. Women may be more sensitive to the effects of marinobufagenin on early structural cardiac changes.
Publisher: Elsevier BV
Date: 07-2018
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
DOI: 10.1161/ATVBAHA.120.313133
Abstract: Early vascular aging reflects increased arterial stiffness of central blood vessels at young chronological ages and powerfully predicts cardiovascular events and mortality, independent of routine brachial blood pressure and other risk factors. Since ethnic disparities exist in routine blood pressure, in hypertension and cardiovascular outcomes, this review evaluates major studies comparing arterial stiffness through the life course between different ethnic groups or races (which have no biological definition)—in children, adolescents, young, and middle-aged adults and the very elderly. Most report that compared with white European-origin s les, populations of black African descent have increased central arterial stiffness throughout different life stages, as well as a more rapid increase in arterial stiffness at young ages. Exceptions may include African Caribbean origin people in Europe. Differences in vascular structure and function are clearest, where obesity, socioeconomic, and psychosocial factors are most marked. Few studies evaluate a wider spectrum of ethnic groups or factors contributing to these ethnic disparities. Genetic effects are not obvious maternal risk and intergenerational studies are scarce. Nevertheless, across all ethnic groups, for given levels of blood pressure and age, some people have stiffer central arteries than others. These in iduals are most at risk of vascular events and mortality and, therefore, may benefit from early, as yet untested, preventive action and treatment.
Publisher: Hindawi Limited
Date: 10-2016
Abstract: The objective of this study was to make use of a quantitative and qualitative approach comparing the systemic renin-angiotensin system (RAS) of hypertensive black and white African men by using RAS equilibrium analysis. This sub-study involved 23 black ( n = 15) and white ( n = 8) hypertensive men aged 39.5–41 years, living in the North West Province of South Africa. The RAS-Fingerprinting was determined with LC-MS/MS quantification of angiotensin peptides. Blood pressure and other variables were determined with known methods. The main finding of this study was the significant lower Ang I ( .0 and 45.1 pg/ml p = 0.005) and Ang II (15.6 and 123.9 pg/ml p ⩽ 0.001) encountered in the hypertensive black African men compared to their white counterparts. Levels of Ang 1-5 (downstream metabolite of Ang 1-7) (1.8 and 3.0 pg/ml), were detected in black and white hypertensive men, respectively. The observed differences between circulating RAS components, which are reflected via equilibrium angiotensin levels, point to a distinctive molecular regulation of the RAAS in the two study cohorts. The increased peripheral resistance observed in hypertensive black in iduals might take over a dominant role in control of blood pressure in this study population. A novel highly sensitive LC-MS/MS method resolved the issue of peptide recovery variations during s le preparation by using internal standards for each in idual angiotensin metabolite.
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 11-2021
Publisher: Springer Science and Business Media LLC
Date: 04-2020
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.IJCARD.2013.07.191
Abstract: Low testosterone, acute and chronic stress and hypercoagulation are all associated with hypertension and hypertension-related diseases. The interaction between these factors and future risk for coronary artery disease in Africans has not been fully elucidated. In this study, associations of testosterone, acute cardiovascular and coagulation stress responses with fibrinogen and von Willebrand factor in African and Caucasian men in a South African cohort were investigated. Cardiovascular variables were studied by means of beat-to-beat and ambulatory blood pressure monitoring. Fasting serum-, salivary testosterone and citrate coagulation markers were obtained from venous blood s les. Acute mental stress responses were evoked with the Stroop test. The African group demonstrated a higher cardiovascular risk compared to Caucasian men with elevated blood pressure, low-grade inflammation, chronic hyperglycemia (HbA1c), lower testosterone levels, and elevated von Willebrand factor (VWF) and fibrinogen levels. Blunted testosterone acute mental stress responses were demonstrated in African males. In multiple regression analyses, higher circulating levels of fibrinogen and VWF in Africans were associated with a low T environment (R(2) 0.24-0.28 p≤0.01), but only circulating fibrinogen in Caucasians. Regarding endothelial function, a low testosterone environment and a profile of augmented α-adrenergic acute mental stress responses (diastolic BP, D-dimer and testosterone) were associated with circulating VWF levels in Africans (Adj R(2) 0.24 p<0.05). An interdependence between acute mental stress, salivary testosterone, D-dimer and vascular responses existed in African males in their association with circulating VWF but no interdependence of the independent variables occurred with fibrinogen levels.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2012
Publisher: Informa UK Limited
Date: 30-08-2021
Publisher: Springer Science and Business Media LLC
Date: 10-05-2022
Publisher: Wiley
Date: 26-10-2012
DOI: 10.1007/S11745-012-3732-8
Abstract: The prevalence of hypertension in sub-Saharan Africa is increasing rapidly, and treatment remains challenging. Although the use of L-carnitine in treatment has received much attention, studies reporting on physiological L-carnitine levels in hypertensives are limited. Our aim was to determine physiological levels of L-carnitine and acylcarnitines in African and Caucasian men, and to investigate associations between ambulatory blood pressure (BP) and carnitine levels. Participants included 101 African and 101 Caucasian teachers. Ambulatory BP measurements were conducted, and L-carnitine and acylcarnitine levels determined. African men showed significantly higher systolic BP (p < 0.001), diastolic BP (p < 0.001) and L-carnitine levels (p = 0.01). In both ethnic groups, partial regression analyses revealed a positive association between BP and L-carnitine, although in Caucasians it was with systolic (r = 0.20, p = 0.045), and in Africans with diastolic BP (r = 0.23, p = 0.023). After adjusting for confounders, an independent positive association between systolic (R(2) = 0.37, β = 0.12, p = 0.041) and diastolic BP (R(2) = 0.39, β = 0.14, p = 0.018) and L-carnitine and long-chain acylcarnitines (R(2) = 0.38, β = 0.17, p = 0.005 and R(2) = 0.39, β = 0.15, p = 0.011) were found, independent of ethnicity. Physiological L-carnitine levels were not only higher in Africans than in Caucasians but also above the expected reference range. Despite promising results on L-carnitine (and its short-chain derivatives) in hypertension treatment regimens, our findings paradoxically show that elevated BP is significantly associated with higher physiological L-carnitine and long-chain acylcarnitine levels.
Publisher: Springer Science and Business Media LLC
Date: 29-03-2023
DOI: 10.1038/S41586-023-05772-8
Abstract: Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being 1–6 . Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was .1 kg m –2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have lified.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-07-2022
Publisher: Frontiers Media SA
Date: 29-04-2020
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.HLC.2014.09.019
Abstract: Fibulin-1 and soluble urokinase-type plasminogen activator receptor (suPAR) emerged as mediators in the development of sclerotic disease. SuPAR along with C-reactive protein (CRP) and albumin delineate inflammatory processes associated with extracellular matrix turnover in atherosclerosis. We explored the independent relationship of fibulin-1 with these inflammatory markers in a bi-ethnic South African population. This study included 290 Africans (men: n=130 and women: n=160) and 343 sex- and age-matched Caucasians (men: n=160 and women: n=183). Serum fibulin-1, suPAR, CRP and albumin levels were measured along with conventional cardiovascular and metabolic variables. In both single and age-adjusted regression analyses, fibulin-1 correlated with both suPAR and albumin in African men and with suPAR in Caucasian men. These findings were absent in women. In multivariate regression analysis, these associations were confirmed in African men (R(2)=0.22 β=0.329 p<0.001) and Caucasian men (R(2)=0.14 β=0.234 p=0.008). Fibulin-1 independently associated positively with suPAR in all men, but inversely with albumin in African men only. These results are indicating the presence of potential subclinical inflammation (suPAR) within the extracellular matrix of endothelial tissue, contributing to the potential onset of cardiac fibrosis or vascular sclerosis among these South African men with lower albumin levels.
Publisher: Informa UK Limited
Date: 21-10-2020
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.ATHEROSCLEROSIS.2012.01.045
Abstract: The N-terminal prohormone B-type natriuretic peptide (NT-proBNP) is involved in the regulation of volume load and secreted when systemic cardiac overload occurs. Fibulin-1 on the other hand is a component of many extracellular matrix proteins including those present in atherosclerotic lesions, expressed in elastin-containing fibres of blood vessels, and also in the heart. Due to an alarming prevalence of hypertensive heart disease in black South Africans, we investigated the associations of NT-proBNP with fibulin-1 and markers of arterial stiffness in Africans and Caucasians. We included 231 Africans and 238 Caucasians from South Africa aged 22-77 years. Serum NT-proBNP and fibulin-1 levels were determined, and arterial compliance and pulse wave velocity were measured. Africans had significantly higher blood pressure and NT-proBNP levels than Caucasians and African men had higher fibulin-1 levels than Caucasian men. In single regression analysis, NT-proBNP was significantly associated with fibulin-1 in African men and Caucasian women. NT-proBNP correlated negatively with arterial compliance in all groups except Caucasian women. After partial adjustments, the association between NT-proBNP and fibulin-1 strengthened in African men only. After full adjustment in multiple regression analysis, the association of NT-proBNP with fibulin-1 was confirmed in African men (R(2)=0.41 β=0.26 p<0.01) and also in younger women (R(2)=0.34 β=0.251 p=0.012). Only Africans indicated a significant independent association between NT-proBNP and fibulin-1, suggesting that cardiovascular alterations are already present in this relatively young African population as opposed to Caucasians.
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.CLNU.2018.05.008
Abstract: The relationship between total body iron and cardiovascular disease remains controversial and information absent in black sub-Saharan Africans in whom alcohol consumption tends to be high. The level of total body iron is tightly regulated, however this regulation is compromised by high alcohol intake causing iron loading. The aim of this study is to investigate total body iron, as represented by serum ferritin, and its interaction with measures of alcohol intake in predicting all-cause and cardiovascular mortality. We followed health outcomes for a median of 9.22 years in 877 randomly selected HIV negative African women (mean age: 50.4 years). One hundred and five deaths occurred of which 40 were cardiovascular related. Ferritin averaged 84.0 (5th to 95th percentile interval, 7.5-533.3) ng/ml and due to the augmenting effect of inflammation, lowered to 75.3 (6.9-523.2) ng/ml after excluding 271 participants with high-sensitivity C-reactive protein (CRP) levels (above 8 mg/l). CRP increased by quartiles of ferritin in the total group (P trend = 0.002), but this relationship was absent after excluding the 271 participants with high CRP values (P trend = 0.10). Ferritin, gamma-glutamyl transferase and carbohydrate deficient transferrin (all P < 0.0001) were higher in drinkers compared to non-drinkers, but CRP was similar (P = 0.77). In multivariable-adjusted analyses, ferritin predicted both all-cause (hazard ratio, 2.08 95% confidence interval, 1.62-2.68 P < 0.0001) and cardiovascular (1.94 1.29-2.92 P = 0.002) mortality. In participants with CRP levels below or equal to 8 mg/l, the significant relationship remained between ferritin and all-cause (2.51 1.81-3.49 P < 0.0001) and cardiovascular mortality (2.34 1.45-3.76 P = 0.0005). In fully adjusted models, interactions existed between ferritin and gamma-glutamyl transferase, self-reported alcohol use and carbohydrate deficient transferrin in predicting all-cause (P ≤ 0.012) and cardiovascular mortality (P ≤ 0.003). Iron loading in African women predicted all-cause and cardiovascular mortality and the intake of alcohol seems mechanistically implicated.
Publisher: BMJ
Date: 08-2021
DOI: 10.1136/BMJGH-2021-006454
Abstract: Chronic kidney disease (CKD) is a global public health problem, seemingly affecting in iduals from low-income and-middle-income countries (LMICs) disproportionately, especially in sub-Saharan Africa. Despite the growing evidence pointing to an increasing prevalence of CKD across Africa, there has not been an Africa-wide concerted effort to provide reliable estimates that could adequately inform health services planning and policy development to address the consequences of CKD. Therefore, we established the CKD in Africa (CKD-Africa) Collaboration. To date, the network has curated data from 39 studies conducted in 12 African countries, totalling 35 747 participants, of which most are from sub-Saharan Africa. We are, however, continuously seeking further collaborations with other groups who have suitable data to grow the network. Although many successful research consortia exist, few papers have been published (with none from Africa) detailing the challenges faced and lessons learnt in setting up and managing a research consortium. Drawing on our experience, we describe the steps taken and the key factors required to establish a functional collaborative consortium among researchers in Africa. In addition, we present the challenges we encountered in building our network, how we managed those challenges and the benefit of such a collaboration for Africa. Although the CKD-Africa Collaboration is focused primarily on CKD research, many of the lessons learnt can be applied more widely in public health research in LMICs.
Publisher: Oxford University Press (OUP)
Date: 06-01-2019
Abstract: 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 in idual-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 s ling 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 in iduals. The prospective African-PREDICT study in young black and white adults will contribute to a clear understanding of early cardiovascular disease development.
Publisher: Springer Science and Business Media LLC
Date: 11-2013
DOI: 10.1007/S00726-013-1611-0
Abstract: Globally the prevalence of non-communicable diseases, such as hypertension and type 2 diabetes, are escalating. Metabolomic studies indicated that circulating branched chain amino acids (BCAAs) are associated with insulin resistance, coronary artery disease and increased risk for cardiovascular events. We aimed to extend the current understanding of the cardiovascular risk associated with BCAAs. We explored whether BCAAs are related to markers of cardiovascular disease in a bi-ethnic population and whether this relationship was influenced by chronic hyperglycaemia. We included 200 African and 209 Caucasian participants, and determined their ambulatory blood pressure and carotid intima-media thickness (cIMT). We analysed blood s les for glycated haemoglobin (HbA1c) and BCAAs. Participants were stratified into two groups according to their HbA1c value using the median cut-off value of 5.6%. Ambulatory BP, cIMT and BCAAs were significantly higher (all p < 0.001) in the high HbA1c group. Single regression analyses indicated significant positive associations of ambulatory blood pressure and cIMT with BCAAs (all p < 0.05) in both the groups. These associations between ambulatory systolic blood pressure (SBP) (r = 0.16, p = 0.035) and cIMT (r = 0.22, p = 0.004) with BCAAs remained in the high HbA1c group after adjusting for age, gender, ethnicity and body mass index (BMI) and were confirmed in multiple regression analyses (ambulatory SBP: R (2) = 0.17, β = 0.21, p = 0.005 and cIMT: R (2) = 0.30, β = 0.19, p = 0.003). Our results demonstrate that BCAAs are independently related to ambulatory BP and cIMT in in iduals with high HbA1c levels and suggest that potential cardiovascular deterioration accompany the rise in BCAAs in conditions of hyperglycaemia.
Location: South Africa
Location: South Africa
Location: South Africa
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Ruan Kruger.