Edelweiss Wentzel-Viljoen

Are behavioural risk factors to be blamed for the conversion from optimal blood pressure to hypertensive status in Black South Africans? A 5-year prospective study

BACKGROUND Longitudinal cohort studies in sub-Saharan Africa are urgently needed to understand cardiovascular disease development. We, therefore, explored health behaviours and conventional risk factors of African individuals with optimal blood pressure (BP) (≤ 120/80 mm Hg), and their 5-year prediction for the development of hypertension. METHODS The Prospective Urban Rural Epidemiology study in the North West Province, South Africa, started in 2005 and included African volunteers (n = 1994; aged > 30 years) from a sample of 6000 randomly selected households in rural and urban areas. RESULTS At baseline, 48% of the participants were hypertensive (≥ 140/90 mmHg). Those with optimal BP (n = 478) were followed at a success rate of 70% for 5 years (213 normotensive, 68 hypertensive, 57 deceased). Africans that became hypertensive smoked more than the normotensive individuals (68.2% vs 49.8%), and they also had a greater waist circumference [ratio of geometric means of 0.94 cm (95% CI: 0.86-0.99)] and greater amount of γ-glutamyltransferase [0.74 U/l (95% CI: 0.62-0.88)] at baseline. The 5-year change in BP was independently explained by baseline γ-glutamyltransferase [R(2) = 0.23, β = 0.13 U/l (95% CI: 0.01-0.19)]. Alcohol intake also predicted central systolic BP and carotid cross-sectional wall area (CSWA) at follow-up. Waist circumference was another predictor of BP changes [β = 0.18 cm (95% CI: 0.05-0.24)] and CSWA. HIV infection was inversely associated with increased BP. CONCLUSIONS During the 5 years, 24% of Africans with optimal BP developed hypertension. The surge in hypertension in Africa is largely explained by modifiable risk factors. Public health strategies should focus aggressively on lifestyle to prevent a catastrophic burden on the national health system.

Added sugar intake in South Africa: findings from the Adult Prospective Urban and Rural Epidemiology cohort study

BACKGROUND Obesity and other noncommunicable disease (NCD) risk factors are increasing in low- and middle-income countries. There are few data on the association between increased added sugar intake and NCD risk in these countries. OBJECTIVE We assessed the relation between added sugar intake and NCD risk factors in an African cohort study. Added sugars were defined as all monosaccharides and disaccharides added to foods and beverages during processing, cooking, and at the table. DESIGN We conducted a 5-y follow-up of a cohort of 2010 urban and rural men and women aged 30-70 y of age at recruitment in 2005 from the North West Province in South Africa. RESULTS Added sugar intake, particularly in rural areas, has increased rapidly in the past 5 y. In rural areas, the proportion of adults who consumed sucrose-sweetened beverages approximately doubled (for men, from 25% to 56%; for women, from 33% to 63%) in the past 5 y. After adjustment, subjects who consumed more added sugars (≥10% energy from added sugars) compared with those who consumed less added sugars had a higher waist circumference [mean difference (95% CI): 1.07 cm (0.35, 1.79 cm)] and body mass index (in kg/m²) [0.43 (0.12, 0.74)] and lower HDL cholesterol [-0.08 mmol/L (-0.14, 0.002 mmol/L)]. CONCLUSIONS This cohort showed dramatic increases in added sugars and sucrose-sweetened beverage consumption in both urban and rural areas. Increased consumption was associated with increased NCD risk factors. In addition, the study showed that the nutrition transition has reached a remote rural area in South Africa. Urgent action is needed to address these trends.

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.

Using different approaches to assess the reproducibility of a culturally sensitive quantified food frequency questionnaire

Abstract Objective: To report on the use of different approaches to assess the reproducibility of a culturally sensitive quantified food frequency questionnaire (QFFQ) used for assessment of the habitual dietary intake of Setswana-speaking adults in the North West Province of South Africa. Method: A previously developed and validated QFFQ was completed by trained fieldworkers. Portion sizes were estimated using different methods. Food intake was coded and analysed for nutrient intake per day for each subject. The first interview (n = 1 888) took place during the baseline data collection period. For the second interview (n = 175), a convenient sample from the subjects who had completed the first interview was collected and the interview was conducted within four to six weeks of the first interview. Results: There were good correlations between the first and second QFFQ for all the nutrients (p < 0.0001). The Wilcoxon signed-rank test showed that there were no significant differences in the median intake between the two administrations, except for energy and total fat. The Bland-Altman plots showed good agreement. Between 41% and 58% of the subjects were correctly classified into the same quartile, with less than 3% grossly misclassified. The weighted κ statistics showed moderate agreement between the two applications. Conclusion: Our results show that more than one statistical approach is needed to assess the reproducibility of a QFFQ. The reproducibility of this culturally sensitive QFFQ was good.AbstractObjective: To report on the use of different approaches to assess the reproducibility of a culturally sensitive quantified food frequency questionnaire (QFFQ) used for assessment of the habitual dietary intake of Setswana-speaking adults in the North West Province of South Africa.Method: A previously developed and validated QFFQ was completed by trained fieldworkers. Portion sizes were estimated using different methods. Food intake was coded and analysed for nutrient intake per day for each subject. The first interview (n = 1 888) took place during the baseline data collection period. For the second interview (n = 175), a convenient sample from the subjects who had completed the first interview was collected and the interview was conducted within four to six weeks of the first interview.Results: There were good correlations between the first and second QFFQ for all the nutrients (p < 0.0001). The Wilcoxon signed-rank test showed that there were no significant differences in the median intake betwe...

A Review of Dietary Surveys in the Adult South African Population from 2000 to 2015

One serious concern of health policymakers in South Africa is the fact that there is no national data on the dietary intake of adult South Africans. The only national dietary study was done in children in 1999. Hence, it becomes difficult to plan intervention and strategies to combat malnutrition without national data on adults. The current review consequently assessed all dietary studies in adults from 2000 to June 2015 in an attempt to portray typical adult dietary intakes and to assess possible dietary deficiencies. Notable findings were that, in South Africa micronutrient deficiencies are still highly prevalent and energy intakes varied between very low intakes in informal settlements to very high intakes in urban centers. The most commonly deficient food groups observed are fruit and vegetables, and dairy. This has been attributed to high prices and lack of availability of these food groups in poorer urban areas and townships. In rural areas, access to healthy foods also remains a problem. A national nutrition monitoring system is recommended in order to identify dietary deficiencies in specific population groups.

Self-reported alcohol intake is a better estimate of 5-year change in blood pressure than biochemical markers in low resource settings: the PURE study

Background: Despite criticism of self-reported alcohol intake, it is a valuable tool to screen for alcohol abuse as a risk factor for cardiovascular disease. We aimed to compare various self-reported estimates of alcohol use with &ggr;-glutamyltransferase (GGT) and percentage carbohydrate deficient transferrin (%CDT) considering their relationship with blood pressure changes (%BP) over a 5-year period in black South Africans. Method: We recruited 1994 participants and collected 5-year followed up data (N = 1246). Participants completed questionnaires on alcohol intake indicating their former and current alcohol use (‘yes’ response and ‘no’ if alcohol was never used). We assessed alcohol intake (in g) using a quantified food frequency questionnaire. We collected blood samples and measured GGT and %CDT. Brachial BP (bBP) was measured at baseline and follow-up and central BP (cBP) at follow-up only. Results: Self-reported alcohol intake was significantly associated with the 5-year change in bBP before and after adjusting for confounders (%bSBP: R2 = 0.263, &bgr; = 0.06, P = 0.023; %bDBP: R2 = 0.326, &bgr; = 0.08 P = 0.005), as well as cSBP (R2 = 0.286, &bgr; = 0.09, P = 0.010) and central pulse pressure (R2 = 0.254, &bgr; = 0.06, P = 0.020). GGT and %CDT correlated well with self-reported alcohol intake (r = 0.44; P = 0.001; r = 0.34 P = 0.001), but did not associate significantly with %bBP or cBP at follow-up. Conclusion: Self-reported alcohol use was strongly associated with a 5-year increase in BP in Africans with a low socio-economic status. This was not found for biochemical measures, GGT and %CDT. Self-reported alcohol intake could be an important measure to implement in primary healthcare settings in middle to low income countries, where honest reporting is expected.

Presentation and interpretation of food intake data: Factors affecting comparability across studies

Non-uniform, unclear, or incomplete presentation of food intake data limits interpretation, usefulness, and comparisons across studies. In this contribution, we discuss factors affecting uniform reporting of food intake across studies. The amount of food eaten can be reported as mean portion size, number of servings or total amount of food consumed per day; the absolute intake value for the specific study depends on the denominator used because food intake data can be presented as per capita intake or for consumers only. To identify the foods mostly consumed, foods are reported and ranked according to total number of times consumed, number of consumers, total intake, or nutrient contribution by individual foods or food groups. Presentation of food intake data primarily depends on a studys aim; reported data thus often are not comparable across studies. Food intake data further depend on the dietary assessment methodology used and foods in the database consulted; and are influenced by the inherent limitations of all dietary assessments. Intake data can be presented as either single foods or as clearly defined food groups. Mixed dishes, reported as such or in terms of ingredients and items added during food preparation remain challenging. Comparable presentation of food consumption data is not always possible; presenting sufficient information will assist valid interpretation and optimal use of the presented data. A checklist was developed to strengthen the reporting of food intake data in science communication.

The use of predefined diet quality scores in the context of CVD risk during urbanization in the South African Prospective Urban and Rural Epidemiological (PURE) study

OBJECTIVE Urbanization is generally associated with increased CVD risk and accompanying dietary changes. Little is known regarding the association between increased CVD risk and dietary changes using approaches such as diet quality. The relevance of predefined diet quality scores (DQS) in non-Western developing countries has not yet been established. DESIGN The association between dietary intakes and CVD risk factors was investigated using two DQS, adapted to the black South African diet. Dietary intake data were collected using a quantitative FFQ. CVD risk was determined by analysing known CVD risk factors. SETTING Urban and rural areas in North West Province, South Africa. SUBJECTS Apparently healthy volunteers from the South African Prospective Urban and Rural Epidemiological (PURE) study population (n 1710). RESULTS CVD risk factors were significantly increased in the urban participants, especially women. Urban men and women had significantly higher intakes of both macro- and micronutrients with macronutrient intakes well within the recommended CVD guidelines. While micronutrient intakes were generally higher in the urban groups than in the rural groups, intakes of selected micronutrients were low in both groups. Both DQS indicated improved diet quality in the urban groups and good agreement was shown between the scores, although they seemed to measure different aspects of diet quality. CONCLUSIONS The apparent paradox between improved diet quality and increased CVD risk in the urban groups can be explained when interpreting the cut-offs used in the scores against the absolute intakes of individual nutrients. Predefined DQS as well as current guidelines for CVD prevention should be interpreted with caution in non-Western developing countries.

Rural and urban older African caregivers coping with HIV/AIDS are nutritionally compromised.

This article describes the nutritional status of a group of rural and urban free living African older surrogate parents caring for HIV/AIDS orphans and grandchildren. Multiple sources of data collection were used, including anthropometry, biochemical analyses, and quantitative questionnaires. The diets of these older participants were marginal. The rural to urban geographical transition in these older persons is characterized by a better micronutrient and trace element intake; however, urban dwellers also had higher fat intakes, increasing the risk for cardiovascular disease. These results suggest that to be a surrogate grandparent provides a special meaning to the life of men that needs to be better understood. However, the diets of these older people caring for HIV/AIDS-affected children were more compromised than those of non-caregivers.

Plasma polyunsaturated fatty acids and liver enzymes in HIV-infected subjects: the Prospective Urban and Rural Epidemiology (PURE) Study

BACKGROUND Omega-6 (n-6) polyunsaturated fatty acid (PUFA) intake was previously reported to be adversely related to liver function in HIV-infected subjects, when compared with HIV-uninfected subjects, in a black population in South Africa. It was speculated that the use of heavily oxidized vegetable fats (abused fats) could have been responsible. OBJECTIVES The objectives were to investigate the relation between plasma total PUFA concentrations (a marker of PUFA intake) and liver enzymes in HIV-infected asymptomatic compared with HIV-uninfected black South Africans and to investigate the reuse of oil and the use of abused oils. DESIGN This was a case-control study nested in an epidemiologic study in 305 HIV-infected cases and 301 HIV-uninfected matched controls (matched according to location, sex, and age), as part of the PURE (Prospective Urban and Rural Epidemiology) Study, a prospective cohort study that includes a representative sample of 2000 apparently healthy black volunteers, aged between 36 and 60 y, from the North West Province of South Africa. RESULTS Plasma total omega-6 PUFA concentrations were negatively (P < 0.05) associated with liver enzymes (gamma-glutamyl transpeptidase, alanine aminotransferase, aspartate aminotranferase, and alkaline phosphatase) in both HIV-infected and HIV-uninfected subjects (r values ranged from -0.22 to -0.56). Almost all subjects (99%) reported that they did not buy oil that had been used before. Oil was only used a mean (+/-SD) of 2.23 +/- 0.85 times for deep frying before being discarded. CONCLUSIONS The adverse relations between omega-6 PUFA intake and liver enzymes that were previously shown could not be confirmed in this study. In contrast, plasma omega-6 PUFA concentration was inversely related to liver enzymes in both HIV-infected and HIV-uninfected subjects. Subjects in this study did not use abused fats, which could partly explain these findings.