Urban Black South African Women Research Articles

Magnesium Intake Predicts Bone Turnover in Postmenopausal Black South African Women.

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.

The Influence of Objectively Measured Physical Activity During Pregnancy on Maternal and Birth Outcomes in Urban Black South African Women

Objectives Research indicates the beneficial effects of physical activity during pregnancy on maternal health, although controversy still exists regarding its influence on birth outcomes. Little research has been done to objectively measure physical activity during pregnancy in black African women from low-to-middle income countries. The purpose of this study was to examine the association between physical activity and maternal and birth outcomes in this unique population. Methods This observational, longitudinal study assessed total physical activity using a hip-mounted triaxial accelerometer at 14–18 weeks (second trimester, n = 120) and 29–33 weeks (third trimester, n = 90) gestation. Physical activity is expressed as gravity-based acceleration units (mg). Maternal outcomes included both weight and weight gain at 29–33 weeks gestation. Birth outcomes included gestational age, birth weight, ponderal index and Apgar score, measured within 48 h of delivery. Results There was a significant decline in physical activity from the second to the third trimester (12.8 ± 4.1 mg vs. 9.7 ± 3.6 mg, p ≤ 0.01). Physical activity at 29–33 weeks as well as a change in PA was inversely associated with weight change at 29–33 weeks (β = − 0.24; 95% CI − 0.49; − 0.00; p = 0.05 and β = − 0.36; 95% CI − 0.62; − 0.10; p = 0.01, respectively). No significant associations were found between physical activity and birth outcomes. Conclusions for Practice Physical activity during pregnancy may be an effective method to control gestational weight gain, whilst presenting no adverse risk for fetal development, in women from a low-income urban setting.

The Influence of Maternal Dietary Patterns on Body Mass Index and Gestational Weight Gain in Urban Black South African Women

Maternal pre-pregnancy body mass index (BMI) and subsequent gestational weight gain (GWG) are strong predictors of maternal and infant outcomes; however the influence of dietary patterns on BMI-specific GWG is unclear. This study identifies patterns of habitual dietary intake in urban South African women and explores their associations with first trimester BMI and GWG. Habitual dietary intake of 538 pregnant women was assessed using a quantitative food-frequency questionnaire and dietary patterns were depicted via principle component analysis. Associations between dietary patterns and BMI-specific GWG were analyzed using linear and logistic regression. Three dietary patterns were identified: Western, Traditional and Mixed. Western and Mixed diet patterns were associated with 35 g/week (p = 0.021) and 24 g/week (p = 0.041) higher GWG in normal weight and obese women respectively. Additionally, high intakes of a Traditional diet pattern were associated with a reduced odds of excessive weight gain in the total sample (OR: 0.81; p = 0.006) and in normal weight women (OR: 0.68; p = 0.003). Increased intake of a traditional diet pattern—high in whole grains, legumes, vegetables and traditional meats—and decreased intake of refined, high sugar and fat driven diets may reduce GWG (including risk of excessive weight gain) in urban South African women.

The Role of Body Fat and Fat Distribution in Hypertension Risk in Urban Black South African Women.

Developing countries are disproportionately affected by hypertension, with Black women being at greater risk, possibly due to differences in body fat distribution. The objectives of this study were: (1) To examine how different measures of body composition are associated with blood pressure (BP) and incident hypertension; (2) to determine the association between baseline or change in body composition, and hypertension; and (3) to determine which body composition measure best predicts hypertension in Black South African women. The sample comprised 478 non-hypertensive women, aged 29–53 years. Body fat and BP were assessed at baseline and 8.3 years later. Body composition was assessed using dual-energy X-ray absorptiometry (DXA) (n = 273) and anthropometry. Hypertension was diagnosed based on a systolic/diastolic BP ≥140/90 mmHg, or medication use at follow-up. All body composition measures increased (p<0.0001) between baseline and follow-up. SBP and DBP increased by ≥20%, resulting in a 57.1% cumulative incidence of hypertension. Both DXA- and anthropometric-derived measures of body composition were significantly associated with BP, explaining 3–5% of the variance. Baseline BP was the most important predictor of hypertension (adjusted OR: 98–123%). Measures of central adiposity were associated with greater odds (50–65%) of hypertension than total adiposity (44–45%). Only change in anthropometric-derived central fat mass predicted hypertension (adjusted OR: 32–40%). This study highlights that body composition is not a major determinant of hypertension in the sample of black African women. DXA measures of body composition do not add to hypertension prediction beyond anthropometry, which is especially relevant for African populations globally, taking into account the severely resource limited setting found in these communities.

Older urban Black South African women are increasingly at risk of low bone mass and high bone turnover

Searchable abstracts of presentations at key conferences on calcified tissues ISSN 2052-1219 (online)

Cardiorespiratory Fitness and Light-Intensity Physical Activity Are Independently Associated with Reduced Cardiovascular Disease Risk in Urban Black South African Women: A Cross-Sectional Study.

Low levels of physical activity, poor cardiorespiratory fitness, and a sedentary lifestyle have been associated with increased risk for cardiovascular disease (CVD) and type 2 diabetes (T2D). Few studies have examined their independent associations in an urban black sub-Saharan African population. To examine the independent associations of physical activity, cardiorespiratory fitness, and sedentary time on body composition and cardiometabolic risk factors for CVD and T2D in black South African women. A subsample (n = 76; 18-45 years) was recruited, as part of a cross-sectional study. Accelerometry, cardiorespiratory fitness, body composition, insulin sensitivity, serum lipids, and blood pressure were measured. Light- but not moderate- to vigorous intensity physical activity was inversely associated with trunk fat mass (r = -0.25, P = 0.03). Sedentary time was associated with triglyceride (TG) (r = 0.36, P = 0.01) and TG/HDL-C (r = 0.34, P = 0.04), and these relationships were independent of body fat. Cardiorespiratory fitness was inversely associated with body fat % (r = -0.34, P = 0.02), central fat mass (r = -0.31, P = 0.03), visceral adipose tissue (VAT, r = -0.47, P < 0.01), and insulin resistance (HOMA-IR; r = -0.41, P = 0.01). The association between cardiorespiratory fitness and HOMA-IR was independent of body fat and physical activity, but not VAT. Cardiorespiratory fitness was inversely associated with sedentary time (r = -0.31, P = 0.03), but not with any of the physical activity variables (P > 0.05). Both physical activity and cardiorespiratory fitness were associated with reduced total and central fat mass, VAT, and reduced cardiometabolic risk for CVD and T2D. Longitudinal studies are required to confirm whether the promotion of increasing light physical activity, while reducing sedentary time and increasing cardiorespiratory fitness, reduces the risk for obesity, CVD and T2D.

Lean Mass Appears to Be More Strongly Associated with Bone Health than Fat Mass in Urban Black South African Women.

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.

Influence of Cut-Points on Patterns of Accelerometry-Measured Free-Living Physical Activity in Rural and Urban Black South African Women

We describe the effect of 2 different accelerometer cut-points on physical activity (PA) patterns in rural and urban black South African women. Hip-mounted uni-axial accelerometers were worn for 6 to 7 days by rural (n = 272) and urban (n = 16) participants. Twenty-hour (4 AM to 12 AM) PA counts (cts) and volumes (min·day⁻¹) were extracted: sedentary (SED, <100 cts·min⁻¹), light (100-759 cts·min⁻¹), moderate-1 (MOD1, 760-1951 cts·min⁻¹), moderate-2 to vigorous (MOD2VG, ≥1952 cts·min⁻¹), and bouts ≥10 min for ≥760 cts·min⁻¹ (MOD1VGbt) and ≥1952 cts·min⁻¹ (MOD2VGbt). Valid data were obtained from 263 rural women and 16 urban women. Total counts and average counts were higher (+80,399 cts·day⁻¹, +98 cts·min⁻¹.day⁻¹) (P < .01), SED lower (-61 min·day⁻¹, P = .0042), MOD1 higher (+65 min·day⁻¹, P < .0001), and MOD1VGbt higher (+19 min·day⁻¹, P = .0179) in rural women compared with urban women. Estimated adherence (≥30 min·day⁻¹ for 5 days·wk⁻¹) was 1.4-fold higher in rural women than urban women for MOD-1VGbt, but 3.3-fold higher in urban women than rural women for MOD2VGbt. Rural women accumulate greater amounts of PA than urban women within a particular count band. Depending on which moderate PA cut-point was used to estimate PA public health adherence, rural women could be classified as less physically active than urban women.

Perceptions of body size and its association with HIV/AIDS

Objective: To explore the perception among black South African women that people who are thin are infected with HIV or have AIDS.Setting: Khayelitsha, an urban township in Cape Town.Subjects: 513 women aged 18–65 years.Methods: This was an exploratory study employing both quantitative and qualitative research methodology. Data were collected in two phases. The first phase involved collecting quantitative data among 513 participants. During the second phase, qualitative data were collected in a purposely selected sub-sample of 20 women. For the qualitative data collection, participants were shown eight body figures, ranging from thin to obese, and asked to choose a figure representing the ideal figure, a preferred figure and a figure thought to symbolise health. They were also invited to choose a figure that they thought represented a person infected with HIV or who had AIDS. They had the option of saying that they did not associate any of the figures with people infected with HIV or who had AIDS. Weight and height measurements were also taken. After the quantitative analysis was completed, focus group discussions explored perceptions about body image and the relation to HIV among purposely selected participants. Data were summarised by content based on questions discussed.Results: Sixty-nine per cent of the participants associated a thin figure with a person infected with HIV, or who had AIDS. Only 10.2% thought the thin figure symbolised health. Fifty per cent preferred a normal-weight figure, while 34.2% thought that normal weight symbolised health. Only 2% thought that people in the normal-weight category were infected with HIV or had AIDS.Thirty-four per cent preferred to be overweight and 31% thought that being overweight symbolised health. None of the participants thought the overweight figure represented people infected with HIV or who had AIDS. Only 8% preferred the obese figure. The results of the qualitative data analysis suggested that participants preferred to be overweight and at risk of acquiring cardiovascular diseases, rather than being thin and stigmatised as a person infected with HIV or who had AIDS.Conclusion: This study revealed that the stigma associated with HIV and AIDS may undermine strategies for prevention of chronic non-communicable diseases among urban black South African women.

Sources and credibility of nutrition information among black urban South African women, with a focus on messages related to obesity.

(1) To identify the major sources of nutrition information, and the perceived credibility thereof, among urban black South African women; and (2) to determine the level of knowledge regarding nutrition, particularly regarding the topic of obesity. A cross-sectional descriptive study that was both qualitative (focus groups) and quantitative (individual questionnaires). Three hundred and ninety-four black women aged 17-49 years were conveniently sampled from the Western Cape and Gauteng provinces in South Africa. Four focus groups were held with 39 women to identify common themes relating to nutrition knowledge. Based on these data, a questionnaire instrument was developed and administered to 394 women by trained fieldworkers. The most frequently encountered source of nutrition information was the media, particularly the radio and TV (73.4% and 72.1% of subjects, respectively, obtained information from this source in the past year), followed by family/friends (64.6%). Despite only 48.5% of subjects having received nutrition information from a health professional, this was the most highly credible information source. Factors being most influential in choice of foods were taste, preferences of the rest of the family, and price. A lack of knowledge on certain aspects of nutrition was identified, as well as misconceptions regarding diet and obesity. To improve nutrition knowledge and the effectiveness of nutrition education activities in South Africa, it is recommended that health and nutrition educators become more actively involved with the training of health professionals, particularly those engaged in delivery of services at primary care level, and in turn encourage health professionals to engage more with media sources. Nutrition messages delivered from health professionals via the media will enable public exposure to nutrition information which is not only easily accessible but also perceived to be highly credible.

Pregnancy outcomes in urban black South African women aged 35 years and older

We measured maternal and fetal outcomes for black South African women of age 35 years and above, compared with younger controls. The study was carried out at the Chris Hani Baragwanath Maternity Hospital and the Soweto Community Health Centres, that provide maternity services for urban black pregnant women. This was a retrospective pregnancy cohort, comparing pregnant women aged 35 and above with a control group aged 20-29 years. Early pregnancy losses (<20 weeks) were excluded. There were 1047 women in each arm of the study. Frequencies of hypertension (22.8%), gestational diabetes (0.9%), and prelabour rupture of the membranes (6.9%) were significantly higher for older women. Perinatal mortality rates (42/1000 vs. 33/1000) did not differ significantly. Antepartum admission, induction of labour, caesarean section and neonatal admission were required more frequently in older women. We conclude that pregnancy at age 35 years and above is often difficult and expensive, requiring hospital based interventions to maintain a low perinatal mortality rate.

Diet and follicular development

In Caucasian women, the length of the menstrual cycle is 28 days with a SD of 3.9 days. Many factors including diet modify menstrual periodicity. We have determined the effect of a meatless vegetarian diet in Caucasian women on the length of the menstrual cycle and the episodic and luteinizing releasing hormone-stimulated release of luteinizing hormone. The effect of a Western diet on the menstrual cycle in urban Black South African women was also studied. In Caucasian women, the vegetarian diet decreased (p ≤ 0.01) the pituitary response to luteinizing releasing hormone and decreased (p ≤ 0.05) the episodic release of luteinizing hormone. A Western diet increased (p ≤ 0.01) the duration of the follicular phase in Black South African women. Thus diet is a factor modifying the episodic release of gonadotropins and follicular maturation.