ORCID Profile
0000-0002-8636-7174
Current Organisations
North-West University
,
North-West University , South Africa
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 14-08-2015
DOI: 10.1038/JHH.2014.71
Abstract: Vascular calcification and cardiovascular diseases have been associated with altered bone metabolism. We explored the relationships of arterial pressures and carotid intima-media thickness (CIMT) with parathyroid hormone, 25-hydroxycholecalciferol and their ratio (PTH:25(OH)D3) as well as a marker of bone resorption (CTX) in lean and overweight/obese African women. A population of 434 African women older than 46 years was ided into lean and overweight/obese groups. We assessed brachial blood pressure, central pulse pressure (cPP) and CIMT, and determined PTH, 25(OH)D3 and CTX concentrations. Overweight/obese women had elevated PTH and PTH:25(OH)D3 compared with lean women (both P<0.001), whereas lean women had higher CTX (P<0.001). Single, partial and multiple regression analyses indicated that, in lean women CIMT was independently associated with PTH:25(OH)D3 (R(2)=0.22 β=0.26 P=0.003), whereas in obese women cPP was associated with both PTH:25(OH)D3 (R2=0.20 β=0.17 P=0.017) and CTX (R2=0.20 β=0.17 P=0.025). In conclusion, we found that in African women with increased adiposity, cPP (as a surrogate measure of arterial stiffness), was positively associated with alterations in bone metabolism and calciotropic hormones, whereas CIMT of lean women was positively associated with PTH:25(OH)D3. Our results suggest that alterations in bone and calcium metabolism may contribute to arterial calcification in older African women.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.DIABRES.2009.04.014
Abstract: Ageing is associated with increased insulin and C-peptide levels. Due to a lack of data, our first aim was to establish whether this also holds true for Africans from South Africa. Our second aim was to determine whether an association between insulin/C-peptide levels and blood pressure exist within an African and Caucasian population with increasing age, as well as to establish gender differences. African men and women (N=260) and Caucasian men and women (N=369) were recruited and stratified into age groups (18-35 years, 36-45 years and >45 years). ANCOVAs and partial correlations were performed. Results showed opposing changes in insulin/C-peptide levels of African and Caucasian men with increasing age. Insulin/C-peptide tended to decrease in African men, whereas insulin tended to increase and C-peptide increased significantly (p=0.03) in Caucasian men. Despite similar obesity levels, the oldest African women had significantly lower insulin (p<0.01) and C-peptide (p<0.01) levels compared to their Caucasian counterparts. In conclusion, insulin/C-peptide levels tended to decrease in the African population with increasing age. Despite significantly lower levels of insulin, blood pressure levels of African men seems to be affected more detrimentally compared to their Caucasian counterparts, leaving them more vulnerable for the development of cardiovascular diseases.
Publisher: Public Library of Science (PLoS)
Date: 23-01-2013
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: American Medical Association (AMA)
Date: 10-2020
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: MDPI AG
Date: 18-10-2019
DOI: 10.3390/NU11102519
Abstract: This prospective study investigated the association between nutrient intake, dietary patterns, and changes in bone turnover and bone mineral density (BMD) in postmenopausal urban black South African women over two years. These women (n = 144) underwent BMD measurements at the distal radius, lumbar spine, femoral neck (FN), as well as a biochemical analysis which included the parathyroid hormone (PTH), 25-hydroxyvitamin D, C-Telopeptide of type I collagen (CTX-1) in 2010 and 2012. Their dietary intake was assessed in 2010 using a food frequency questionnaire, and sociodemographic and health information was collected. Four dietary patterns explained 54.4% of the variance of dietary intake, namely staple foods and processed meats, home cooking, snacking, and high sugar. Dietary magnesium negatively correlated with CTx-1 in 2012 (r = −0.21, p = 0.02), calcium correlated with distal radius BMD in 2010 (r = 0.22, p = 0.01) and 2012 (r = 0.24, p = 0.005), and the snacking dietary pattern score correlated with FN BMD in 2010 (r = 0.18, p = 0.03) and 2012 (r = 0.21, p = 0.02). The baseline CTx-1 and dietary magnesium intake predicted 22% of the variance in percentage change of CTx-1 over two years (p 0.001).The magnesium intake predicted short-term bone resorption over two years.
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: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2019
Publisher: Hindawi Limited
Date: 2018
DOI: 10.1017/GHEG.2018.7
Abstract: Anti-retroviral therapy (ART) regimes for HIV are associated with raised levels of circulating triglycerides (TGs) in western populations. However, there are limited data on the impact of ART on cardiometabolic risk in sub-Saharan African (SSA) populations. Pooled analyses of 14 studies comprising 21 023 in iduals, on whom relevant cardiometabolic risk factors (including TG), HIV and ART status were assessed between 2003 and 2014, in SSA. The association between ART and raised TG ( .3 mmol/L) was analysed using regression models. Among 10 615 in iduals, ART was associated with a two-fold higher probability of raised TG (RR 2.05, 95% CI 1.51–2.77, I2 = 45.2%). The associations between ART and raised blood pressure, glucose, HbA1c, and other lipids were inconsistent across studies. Evidence from this study confirms the association of ART with raised TG in SSA populations. Given the possible causal effect of raised TG on cardiovascular disease (CVD), the evidence highlights the need for prospective studies to clarify the impact of long term ART on CVD outcomes in SSA.
Publisher: MDPI AG
Date: 06-09-2019
DOI: 10.3390/FOODS8090394
Abstract: Nutritional transition in Africa is linked with increased blood pressure (BP). We examined 10-year fatty acid status and longitudinal associations between in idual long-chain polyunsaturated fatty acids (PUFA), BP and status of hypertension (≥140/90 mmHg and/or medication use) in black South Africans. We included 300 adults ( years) participating in the Prospective Urban Rural Epidemiology study, and analysed data from three consecutive examinations (2005, 2010 and 2015 study years). Fatty acids in plasma phospholipids were analysed by gas chromatography-mass spectrometry. We applied sequential linear mixed models for continuous outcomes and generalized mixed models for the hypertension outcome, in the complete s le and separately in urban and rural subjects. Mean baseline systolic/diastolic BP was 137/89 mmHg. Ten-year hypertension status increased among rural (48.6% to 68.6%, p = 0.001) and tended to decrease among urban subjects (67.5% to 61.9%, p = 0.253). Regardless of urbanisation, n-6 PUFA increased and eicosapentaenoic acid (EPA, C20:5 n-3) decreased over the 10-years. Subjects in the highest tertile of arachidonic acid (C20:4 n-6) had 3.81 mmHg lower systolic (95% confidence interval (CI): −7.07, −0.54) and 3.82 mmHg lower diastolic BP (DBP) (95% CI: −5.70, −1.95) compared to the reference tertile, irrespective of lifestyle and clinical confounders. Similarly, osbond acid (C22:5 n-6) was inversely associated with DBP. Over the 10-years, subjects in the highest EPA tertile presented with +2.92 and +1.94 mmHg higher SBP and DBP, respectively, and with 1.46 higher odds of being hypertensive. In black South African adults, in idual plasma n-6 PUFA were inversely associated with BP, whereas EPA was adversely associated with hypertension, supporting implementation of dietary fat quality in national cardiovascular primary prevention strategies.
Publisher: Elsevier BV
Date: 08-2011
DOI: 10.1016/J.REGPEP.2011.04.003
Abstract: Ageing is associated with elevated adiponectin levels. Our aim was to assess whether age-related increase in adiponectin is associated with a decrease in renal function. The study comprised African (N=277) and Caucasian (N=326) men and women. Adiponectin levels, estimated creatinine clearance rate and obesity indices were determined. African men revealed significantly higher adiponectin levels compared to Caucasian men (p<0.01), reflecting the lower adiposity levels of the African men. No difference in obesity measures (p=0.92) and adiponectin levels (p=0.27) was observed between African and Caucasian women. A significant increase in adiponectin levels with ageing was observed in both African men and women (p<0.01). To the contrary, progressive ageing seems not to be significantly related to elevated adiponectin levels within Caucasians. Renal impairment decreased significantly within all of the groups (p<0.01). Single regression analyses performed in all specified groups revealed significant associations between adiponectin and estimated creatinine clearance, however a multiple regression model revealed that insulin resistance had the strongest association with adiponectin within all the groups. In conclusion, age-related rise in adiponectin levels observed in Africans may not be due to renal impairment.
Publisher: Oxford University Press (OUP)
Date: 12-2008
DOI: 10.1038/AJH.2008.287
Abstract: The increasing prevalence of hypertension and vascular-related morbidity and mortality among Africans emphasizes the need to identify markers for the early detection of vascular disease. Caucasian-based studies demonstrate that the von Willebrand factor (vWf) is a useful marker of vascular dysfunction. We investigated whether associations between this marker and markers of cardiovascular function in Caucasian women are comparable with African women. The study consisted of apparently healthy African (n = 99) and Caucasian (n = 114) women (mean age, 31.0 years), in idually matched for age and body mass index. We measured blood pressure and arterial compliance noninvasively, and vWf in serum. We assessed univariate and multivariate-adjusted associations of blood pressure and arterial compliance with vWf. Although no ethnic difference existed for mean vWf levels, Caucasian and African women showed opposite associations of blood pressure and arterial compliance with vWf after single, partial, and multiple regression analyses. In Caucasians, after full adjustment, systolic (beta = +0.179 P < 0.05) and diastolic (beta = +0.190 P < 0.05) blood pressure correlated positively and arterial compliance negatively (beta = -0.197 P 99% power existed, significance disappeared after excluding these subjects (beta = -0.071 P = 0.46). Associations of vWf with blood pressure and arterial compliance were not comparable between Caucasian and African women, suggesting that the vWf may not be a useful marker of vascular alterations in African women.
Publisher: S. Karger AG
Date: 2017
DOI: 10.1159/000480486
Publisher: Wiley
Date: 05-05-2021
DOI: 10.1111/HIV.13111
Abstract: We aimed to determine whether people with human immunodeficiency virus (PWHIV) have increased measures of arterial injury [carotid intima‐media thickness (cIMT)] and large artery stiffness [carotid‐femoral pulse wave velocity (cfPWV)] when compared with their counterparts without HIV, and whether baseline markers of endothelial activation and cardiovascular risk are associated with cIMT and cfPWV after 5 years. We matched 126 PWHIV from North West Province, South Africa, to 126 without HIV according to age, sex and locality. Cardiovascular risk and endothelial function markers [soluble intracellular adhesion molecule (ICAM‐1) and soluble vascular cell adhesion molecule (VCAM‐1)] were measured at baseline and cIMT and cfPWV at follow‐up. This study included 21.4% men. The use of antiretroviral therapy (ART) increased from 44.1% at baseline to 81.4% at follow‐up. At follow‐up, cIMT ( P = 0.90) and cfPWV ( P = 0.35) were similar in the groups. Despite elevated ICAM‐1 and VCAM‐1 in the PWHIV (all P 0.001) at baseline, these markers did not associate with cIMT and cfPWV after 5 years. In multivariable‐adjusted regression analysis, cIMT associated positively with age ( β = 0.31, P = 0.002) and triglyceride: high‐density lipoprotein‐cholesterol ( β = 0.23, P = 0.016) in PWHIV. Mean arterial pressure (MAP) ( β = 0.28, P = 0.010) associated positively with cfPWV in the PWHIV. In the people without HIV, sex ( β = 0.31, P = 0.004) and glycated haemoglobin (HbA1c) ( β = 0.24, P = 0.026) associated with cIMT while age ( β = 0.17, P = 0.049), sex ( β = 0.29, P = 0.003), MAP ( β = 0.31, P = 0.001) and HbA1c ( β = 0.21, P = 0.041) associated positively with cfPWV. Measures of arterial structure and function were similar in Africans with HIV and their age, sex and locality matched controls. Traditional cardiovascular risk markers rather than elevated endothelial activation at baseline were independently associated with cIMT and cfPWV over 5 years.
Publisher: BMJ
Date: 11-2020
DOI: 10.1136/BMJGH-2020-002640
Abstract: We aimed to examine the relationship between access to medicine for cardiovascular disease (CVD) and major adverse cardiovascular events (MACEs) among people at high risk of CVD in high-income countries (HICs), upper and lower middle-income countries (UMICs, LMICs) and low-income countries (LICs) participating in the Prospective Urban Rural Epidemiology (PURE) study. We defined high CVD risk as the presence of any of the following: hypertension, coronary artery disease, stroke, smoker, diabetes or age years. Availability and affordability of blood pressure lowering drugs, antiplatelets and statins were obtained from pharmacies. Participants were categorised: group 1—all three drug types were available and affordable, group 2—all three drugs were available but not affordable and group 3—all three drugs were not available. We used multivariable Cox proportional hazard models with nested clustering at country and community levels, adjusting for comorbidities, sociodemographic and economic factors. Of 163 466 participants, there were 93 200 with high CVD risk from 21 countries (mean age 54.7, 49% female). Of these, 44.9% were from group 1, 29.4% from group 2 and 25.7% from group 3. Compared with participants from group 1, the risk of MACEs was higher among participants in group 2 (HR 1.19, 95% CI 1.07 to 1.31), and among participants from group 3 (HR 1.25, 95% CI 1.08 to 1.50). Lower availability and affordability of essential CVD medicines were associated with higher risk of MACEs and mortality. Improving access to CVD medicines should be a key part of the strategy to lower CVD globally.
Publisher: Springer Science and Business Media LLC
Date: 02-03-2015
DOI: 10.1007/S12603-015-0492-1
Abstract: To examine the association between body composition (fat mass, lean mass and body mass index, BMI) and bone health (bone mineral density, BMD and fracture risk) in urban black South African women. A cross sectional study examining associations between body composition, dietary intake (food frequency questionnaire), habitual physical activity (Activity energy expenditure (AEE) measured using an accelerometer with combined heart rate monitor and physical activity questionnaire) and bone health (BMD using dual-energy X ray absorptiometry, DXA and fracture risk). Urban community dwellers from Ikageng in the North-West Province of South Africa. One hundred and eighty nine (189) healthy postmenopausal women aged ≥43 years. Fat mass and lean mass were significantly associated with BMD and fracture risk when adjusted for potential confounders. However, lean mass and not fat mass remained significantly associated with femoral neck BMD (β = 0.49, p <0.001), spine BMD (β = 0.48, p< 0.0001) and hip BMD (β = 0.59, p< 0.0001). Lean mass was also negatively associated with fracture risk (β = -0.19 p =0.04) when both lean and fat mass were in the same model. Lean mass and fat mass were positively associated with femoral neck, spine and hip BMDs and negatively associated with fracture risk in urban black South African women. Our finding suggests that increasing lean mass rather than fat mass is beneficial to bone health. Our study emphasises the importance of positive lifestyle changes, intake of calcium from dairy and adequate weight to maintain and improve bone health of postmenopausal women.
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: Elsevier BV
Date: 03-2020
Publisher: MDPI AG
Date: 20-09-2017
Publisher: Springer Science and Business Media LLC
Date: 11-02-2010
DOI: 10.1038/JHH.2010.1
Abstract: The African population is considered a high-risk group for the development of hypertension, and identifying risk factors are therefore essential in preventive actions against cardiovascular disease (CVD). Elevated levels of uric acid (UA) are often associated with CVD. Our first aim was to establish possible ethnic differences in UA levels between African and Caucasian men. Our second aim was to determine any associations between UA levels and cardio-metabolic variables, and also how these correlates differ between the two groups. African (N=87) and Caucasian (N=121) men participated in this cross-sectional study. Our results have shown that African men had significantly lower (353±87.7 vs 401±98.2 P<0.01) UA levels compared with Caucasian men. Waist circumference and triglycerides correlated strongly with UA in both ethnic groups. This was confirmed with a forward stepwise multiple regression analysis. After adjustment for confounders, the correlation between UA and triglycerides remained significant only in the Caucasians (r=0.29 P=0.02), whereas only the African men showed an independent correlation between UA and total peripheral resistance (TPR) (r=0.23 P=0.04). TPR increased significantly across UA tertiles only in the African men (P=0.01 vs P=0.96). In conclusion, despite their lower UA levels, Africans showed an independent relationship between UA and vascular resistance, indicating a possible explanation for their high prevalence of hypertension.
No related grants have been discovered for Iolanthe M Kruger.