Iolanthé M. Kruger

Urbanization of black South African women may increase risk of low bone mass due to low vitamin D status, low calcium intake, and high bone turnover

Globally, rural to urban migration is accompanied by changes in dietary patterns and lifestyle that have serious health implications, including development of low bone mass. We hypothesized that serum 25 (OH) vitamin D3 (25[OH]D3) levels will be lower, bone turnover higher, and nutrition inadequate in urban postmenopausal black women, increasing risk for low bone mass. We aimed to assess the prevalence of risk factors for low bone mass in 1261 black women from rural and urban areas in the North West Province of South Africa (Prospective Urban and Rural Epidemiology-South Africa project). Fasting blood samples were taken; and participants were interviewed to complete questionnaires on self-reported diseases, fractures, and dietary intakes. Bone health markers were assessed in a subgroup of 658 women older than 45 years. Specific lifestyle risk factors identified were inactivity, smoking, injectable progestin contraception use, and high alcohol consumption. Dietary risk factors identified were low calcium and high animal protein, phosphorous, and sodium intakes. The 25(OH)D3 and C-terminal telopeptide (CTX) levels were significantly higher in the rural vs the urban women older than 50 years. Parathyroid hormone (PTH) levels increased with age in both groups. The 25(OH)D levels were inversely correlated with CTX and PTH in rural women. In urban women, PTH and CTX were correlated while dietary calcium was inversely correlated with CTX and PTH with 25(OH)D3. The combination of low dietary calcium (<230 mg/d), marginally insufficient 25(OH)D3 status, and raised PTH may result in increased bone resorption. Further research is required to assess bone health and fracture risk in black African women.

Evaluation of waist-to-height ratio to predict 5 year cardiometabolic risk in sub-Saharan African adults

BACKGROUND AND AIMS Simple, low-cost central obesity measures may help identify individuals 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 individuals 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. METHODS AND RESULTS 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 < 0.001). In women, both WC and WHtR significantly predicted all cardiometabolic risk factors after 5 years. In men, even after adjusting WC threshold based on ROC analysis, WHtR better predicted overall 5-year risk. Neither measure predicted hypertension in men. CONCLUSIONS The WHtR threshold of >0.5 appears to be more consistently supported and may provide a better predictor of future cardiometabolic risk in sub-Saharan Africa.

The association of 25(OH)D with blood pressure, pulse pressure and carotid-radial pulse wave velocity in African women.

High susceptibility of the African population to develop cardiovascular disease obliges us to investigate possible contributing risk factors. Our aim was to determine whether low 25(OH)D status is associated with increased blood pressure and carotid-radial pulse wave velocity in black South African women. We studied 291 urban women (mean age: 57.56±9.00 yrs.). 25(OH)D status was determined by serum 25(OH)D levels. Women were stratified into sufficient (>30 ng/ml), and insufficient/deficient (<30 ng/ml) groups. Cardiovascular variables were compared between groups. Women with low 25(OH)D levels had significantly higher SBP (150.8±27.1 vs. 137.6±21.0), DBP (94.7±14.5 vs. 89.3±12.3) and PP (53.15(50.7;55.7) vs. 46.3(29.4;84.6)) compared to women with sufficient levels. No significant difference was observed with regards to c-rPWV. ANCOVA analyses still revealed significant differences between the two groups with regards to SBP, DBP as well as PP. Partial correlations revealed significant inverse association between SBP and 25(OH)D (p = .04;r = −.12). Women with low 25(OH)D levels were ∼2 times more likely to have high SBP (95% CI: 3.23;1.05). To conclude, women with deficient/insufficient 25(OH)D had significantly higher SBP compared to women with a sufficient 25(OH) status.

The relationship between adiponectin, ageing and renal function in a bi-ethnic sample

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.

Urinary albumin excretion from spot urine samples predict all-cause and stroke mortality in Africans.

BACKGROUND Increased urinary albumin excretion reflects general vascular damage and predicts adverse cardiovascular and renal outcomes. Albuminuria can be determined from easily collected spot urine samples, especially in low-resource settings. However, no prognostic evidence exists for Africans. METHODS 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 samples. RESULTS 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. CONCLUSION In nondiabetic HIV-negative Africans, albuminuria predicts all-cause and stroke mortality.

Cut-off values of distal forearm bone density for the diagnosis of central osteoporosis in black postmenopausal South African women

Abstract Background: The objective of this study was to establish a triage cut-off point or threshold for peripheral bone mineral density (BMD), applicable to black postmenopausal women, and that could be used as a screening method to differentiate between women with normal BMD, and those with possible central osteoporosis. This was a cross-sectional study design conducted in the North West province. Central and peripheral BMD was measured in 184 black, urban postmenopausal women. Method: Receiver operating curves (ROC) analysis was used to establish cut-off points. Sensitivity, specificity, positive and negative predictive value, odds ratios and likelihood ratios were determined. Results: The results showed a prevalence rate of 41.3% for central osteoporosis. The area under the curve (AUC) for osteoporosis at the hip was 0.818, and for the spine, it was 0.771. Using the optimum cut-off point (0.371 g/cm2), our results showed a misclassification rate of ≈ 49% for spine osteoporosis, and a negative predictive value of 0.825. Women who had a forearm BMD below this threshold were ∼10 times more likely to have osteoporosis of the spine. Conclusion: We recommend using 0.371 g/cm2 as a cut-off point to differentiate between women who have normal BMD, and those with possible osteoporosis of the spine.

A health profile associated with excessive alcohol use independently predicts aortic stiffness over 10 years in black South Africans

Objective: Black populations exhibit higher arterial stiffness than whites and suffer a disproportionate burden of cardiovascular disease. It is therefore important to identify modifiable health behaviours predicting large artery stiffness in blacks. We examined whether traditional cardiovascular risk factors and health behaviours of black South Africans predict large artery stiffness 10 years later. Methods: We included 650 HIV-free participants (32.8% men) and collected data in rural and urban areas of the North West Province in 2005 and 2015. We collected questionnaire data, anthropometry, blood pressure and determined cardiometabolic and inflammatory markers from blood samples. We measured carotid–femoral pulse wave velocity (PWV) at follow-up. Results: A total of 25.3% of our population, aged 65 ± 9.57 years, had a PWV exceeding 10 m/s. In multivariable-adjusted regression analyses, the strongest predictors of PWV were mean arterial pressure, age and heart rate (all P < 0.024). Urban locality (R2 = 0.31, &bgr; = 0.12, P = 0.001), self-reported alcohol use (&bgr; = 0.11, P = 0.018) and plasma glucose (&bgr; = 0.08 P = 0.023) associated positively with PWV at follow-up. We found a negative association between PWV and BMI (&bgr; = −0.15, P = 0.001), and no associations with sex, smoking, inflammatory markers, lipids, liver enzymes or antihypertensive medication. When replacing self-reported alcohol with gamma-glutamyltransferase, the latter associated positively with PWV (&bgr; = 0.09, P = 0.023). Conclusion: A health profile associated with excessive alcohol use, including an urban setting, elevated plasma glucose and lower BMI predicts large artery stiffness independently of age and blood pressure in black South Africans over 10 years. This observation prompts urgent public health strategies to target alcohol overuse.

Does greater individual social capital improve the management of hypertension? Cross-national analysis of 61 229 individuals in 21 countries

Introduction Social capital, characterised by trust, reciprocity and cooperation, is positively associated with a number of health outcomes. We test the hypothesis that among hypertensive individuals, those with greater social capital are more likely to have their hypertension detected, treated and controlled. Methods Cross-sectional data from 21 countries in the Prospective Urban and Rural Epidemiology study were collected covering 61 229 hypertensive individuals aged 35–70 years, their households and the 656 communities in which they live. Outcomes include whether hypertensive participants have their condition detected, treated and/or controlled. Multivariate statistical models adjusting for community fixed effects were used to assess the associations of three social capital measures: (1) membership of any social organisation, (2) trust in other people and (3) trust in organisations, stratified into high-income and low-income country samples. Results In low-income countries, membership of any social organisation was associated with a 3% greater likelihood of having one’s hypertension detected and controlled, while greater trust in organisations significantly increased the likelihood of detection by 4%. These associations were not observed among participants in high-income countries. Conclusion Although the observed associations are modest, some aspects of social capital are associated with better management of hypertension in low-income countries where health systems are often weak. Given that hypertension affects millions in these countries, even modest gains at all points along the treatment pathway could improve management for many, and translate into the prevention of thousands of cardiovascular events each year.

Changes in body composition and cardiometabolic risk among black South African adults

NMR metabolomic signatures reveal predictive plasma metabolites associated with long-term risk of developing breast cancer. IUNS 21st International Congress of NutritionBackground and objectives: The University of Southampton and International Malnutrition Task Force developed Malnutrition eLearning to reduce child mortality by Severe Acute Malnutrition (SAM) through training health professionals globally. Since made available in 2010, over 14,000 from 100+ countries used the course. To investigate its effectiveness, a 2-year evaluation study was conducted from 2015, face-to-face in Ghana and Central America (CA), and online in other countries.Methods: Using a mixed method approach, the study explored if and how Malnutrition eLearning supported knowledge gain and behavioural change (application of knowledge in clinical practice), and resulting clinical outcomes in the management of SAM. Assessments, questionnaires and interviews/focus groups were conducted with individual in-service and pre-service participants pre- and post-training, and 12 months of medical records data collection, observations and hospital personnel interviews were carried out from participating healthcare institutions.Results: Total 1,261 health professionals (Ghana:915, CA:142, other countries:201), and 10 hospitals and 2 community health centres in Ghana and 2 hospitals in CA participated in the study. 3,955 (pre:01/08/2014–31/07/2015) and 3,737 (post:01/08/2015– 31/07/2016) medical records of children (0-60 months) were collected from the hospitals, and summary data on malnutrition cases (pre:76, post:67) from community health centres. Individual participants scored significantly higher in the post assessment (mean difference(SD): 14.0(12.5), 95%CI(12.7, 15.2), p<0.001). 87% of in-service health professionals (102/117) applied their knowledge and changed clinical practice in screening, assessment, diagnosis and management of SAM. This group demonstrated retained knowledge 6-month after the training (mean difference from pre-assessment(SD): 12.7(11.7), 95%CI(10.4, 15.0),p<0.001). Significant increases (p<0.001) in recording malnutrition-markers, i.e. length/height and weight-for-length/ height z-score, and diagnosed SAM cases (pre: 491(12.4%), post: 810(21.7%)) were observed. Mortality by SAM was declined from 26(5.9%) to 14(1.9%) (p<0.001). The community centres initiated the management of SAM (pre:0/32, post:7/21).Conclusions: The results suggest that Malnutrition eLearning is effective in training the WHO guideline on the management of SAM. After a 2-day self-directed training with Malnutrition eLearning, the participants not only gained knowledge but were also able to apply the knowledge in their clinical practice, leading to significant impacts on clinical outcomes.Acknowledgement: This study was supported by the UK Department for International Development Nutrition Embedding Evaluation Programme, managed by PATH.This paper was presented at IUNS 21st International Congress of Nutrition, Buenos Aires, Argentina, 15-20 October. This is the peer-reviewed but unedited manuscript version of the following article: MARKEY, O. ...et al., 2017. Postprandial lipid responses after long-term intake of dairy products varying in fatty acid composition. Annals of Nutrition and Metabolism, 71 (Suppl 2), pp. 346 (DOI: 10.1159/000480486). The final, published version is available at https://doi.org/10.1159/000480486

Cardiac troponin T as early marker of subclinical cardiovascular deterioration in black hypertensive women

BACKGROUND 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. METHODS 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. RESULTS 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). CONCLUSION 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.