Social drift of cardiovascular disease risk factors in Africans from the North West Province of South Africa: the PURE study

Economic impacts of overweight and obesity: current and future estimates for 161 countries

INTRODUCTION

The scope of the challenge of overweight and obesity (OAO) has not been fully realised globally, in part because much of what is known about the economic impacts of OAO come from high-income countries (HICs) and are not readily comparable due to methodological differences. Our objective is to estimate the current and future national economic impacts of OAO globally.

METHODS

We estimated economic impacts of OAO for 161 countries using a cost-of-illness approach. Direct and indirect costs of OAO between 2019 and 2060 were estimated from a societal perspective. We assessed the effect of two hypothetical scenarios of OAO prevalence projections. Country-specific data were sourced from published studies and global databases.

RESULTS

The economic impact of OAO in 2019 is estimated at 2.19% of global gross domestic product (GDP) ranging on average from US$20 per capita in Africa to US$872 per capita in the Americas and from US$6 in low-income countries to US$1110 in HICs.If current trends continue, by 2060, the economic impacts from OAO are projected to rise to 3.29% of GDP globally. The biggest increase will be concentrated in lower resource countries with total economic costs increasing by fourfold between 2019 and 2060 in HICs, whereas they increase 12-25 times in low and middle-income countries. Reducing projected OAO prevalence by 5% annually from current trends or keeping it at 2019 levels will translate into average annual reductions of US$429 billion or US$2201 billion in costs, respectively, between 2020 and 2060 globally.

CONCLUSION

This study provides novel evidence on the economic impact of OAO across different economic and geographic contexts. Our findings highlight the need for concerted and holistic action to address the global rise in OAO prevalence, to avert the significant risks of inaction and achieve the promise of whole-of-society gains in population well-being.

Prognostic values of modifiable risk factors for cardiovascular events in South African health promotion

Background

Cardiovascular diseases (CVDs) are increasing at an alarming rate among the South African population. This study aimed to determine the prognostic value of modifiable CVD risk factors for fatal and non-fatal events to inform cardiovascular health promotion practices in the South African public health system.

Methods

Data was collected from individuals participating in the South African leg of a multi-national prospective cohort study. Binary logistic regression was applied to estimate odds of total, non-fatal and fatal cardiovascular events.

Results

Binary logistic regression analyses identified age as a predictor of non-fatal and fatal CV events, with ORs of 1.87 to 3.21, respectively. Hypertension increased the odd of suffering a non-fatal CV event by almost two and a half (OR = 2.47; 95% CI = 1.26, 4.85). Moreover, being physically active reduced the odd of non-fatal CVD events by 38% (OR = 0.62; 95% CI = 0.46, 0.83 for 1 Standard deviation increase of the weighted physical activity index score (WPA)). On the one hand, gamma-glutamyltransferase (GGT) was associated with a higher fatal cardiovascular disease risk OR = 2.45 (95% CI = 1.36, 4.42) for a standard deviation increase.

Conclusions

Elevated blood pressure, GGT, and physical activity have significant prognostic values for fatal or non-fatal CV events. These findings emphasise the importance of highlighting hypertension and physical activity when planning cardiovascular health education and intervention programmes for this population, with attention to the monitoring of GGT.

Practice Change Needed for the Identification of Pediatric Hypertension in Marginalized Populations: An Example From South Africa

INTRODUCTION

Hypertension in children has increased globally over the past 20 years; yet, little is known about this issue among disadvantaged communities from low- and middle-income countries. Age-, sex-, and height-adjusted normative tables are the "gold" standard for the diagnosis and estimation of pediatric hypertension worldwide, but it is unclear whether the use of international standards is appropriate for all contexts. The purpose of this study was to evaluate and compare different international references to identify hypertension among South African school-aged children from disadvantaged communities.

METHODS

Blood pressure, weight, and height were measured in a cohort of 897 children aged 8-16 years from eight peri-urban schools in the Eastern Cape of South Africa. Cross-sectional prevalence of hypertension was calculated according to American, German, and global normative tables, as well as pseudo-normative data from the own study population. Isolated systolic hypertension and body mass index (BMI) were considered markers for cardiovascular disease. Multinomial logistic regression was used to compare the likelihood of blood pressure categorization with increasing BMI levels.

RESULTS

Hypertension prevalence ranged from 11.4% with the pseudo-normative study tables to 28.8% based on the German reference. Global guidelines showed the highest agreement both among international standards (92.5% with American guidelines) and with the study reference (72.5%). While the global and the American references presented higher systolic over diastolic hypertension rates (23.6 vs. 10.6% and 24.2 vs. 14.7%, respectively), the American guidelines predicted the highest increased risk for hypertension stage 2 [odds ratio, 1.72 (95% confidence interval: 1.43-2.07)] with raising levels of BMI.

CONCLUSION

Our results support the heterogeneity of blood pressure estimates found in the South African literature, and highlight the underrepresentation of African children in international guidelines. We call for caution in the use of international standards in different contexts and advocate for the development of normative tables that are representative of the South African pediatric population necessary to ensure an accurate identification of hypertension both from the clinical and epidemiological perspective.

Economic impacts of overweight and obesity: current and future estimates for eight countries

BACKGROUND

Obesity is a growing public health challenge worldwide with significant health and economic impacts. However, much of what is known about the economic impacts of obesity comes from high-income countries and studies are not readily comparable due to methodological differences. Our objective is to demonstrate a method for estimating current and future national economic impacts of obesity and apply it across a sample of heterogeneous contexts globally.

METHODS

We estimated economic impacts of overweight and obesity for eight countries using a cost-of-illness approach. Direct and indirect costs of obesity from 2019 to 2060 were estimated from a societal perspective as well as the effect of two hypothetical scenarios of obesity prevalence projections. Country-specific data were sourced from published studies and global databases.

RESULTS

In per capita terms, costs of obesity in 2019 ranged from US$17 in India to US$940 in Australia. These economic costs are comparable to 1.8% of gross domestic product (GDP) on average across the eight countries, ranging from 0.8% of GDP in India to 2.4% in Saudi Arabia. By 2060, with no significant changes to the status quo, the economic impacts from obesity are projected to grow to 3.6% of GDP on average ranging from 2.4% of GDP in Spain to 4.9% of GDP in Thailand. Reducing obesity prevalence by 5% from projected levels or keeping it at 2019 levels will translate into an average annual reduction of 5.2% and 13.2% in economic costs, respectively, between 2020 and 2060 across the eight countries.

CONCLUSION

Our findings demonstrate that the economic impacts of obesity are substantial across countries, irrespective of economic or geographical context and will increase over time if current trends continue. These findings strongly point to the need for advocacy to increase awareness of the societal impacts of obesity, and for policy actions to address the systemic roots of obesity.

Education, Smoking and CRP Genetics in Relation to C-Reactive Protein Concentrations in Black South Africans

Because elevated circulating C-reactive protein (CRP) and low socio-economic status (SES), have both been implicated in cardiovascular disease development, we investigated whether SES factors associate with and interact with CRP polymorphisms in relation to the phenotype. Included in the study were 1569 black South Africans for whom CRP concentrations, 12 CRP single nucleotide polymorphisms (SNPs), cardiovascular health markers, and SES factors were known. None of the investigated SES aspects was found to associate with CRP concentrations when measured individually; however, in adjusted analyses, attaining twelve or more years of formal education resulted in a hypothetically predicted 18.9% lower CRP concentration. We also present the first evidence that active smokers with a C-allele at rs3093068 are at an increased risk of presenting with elevated CRP concentrations. Apart from education level, most SES factors on their own are not associated with the elevated CRP phenotype observed in black South Africans. However, these factors may collectively with other environmental, genetic, and behavioral aspects such as smoking, contribute to the elevated inflammation levels observed in this population. The gene-smoking status interaction in relation to inflammation observed here is of interest and if replicated could be used in at-risk individuals to serve as an additional motivation to quit.

Determinants of Mortality from Cardiovascular Disease in the Slums of Nairobi, Kenya

Background

Cardiovascular diseases (CVD) comprise eighty percent of non-communicable disease (NCD) burden in low- and middle-income countries and are increasingly impacting the poor inequitably. Traditional and socioeconomic factors were analyzed for their association with CVD mortality over 10 years of baseline assessment in an urban slum of Nairobi, Kenya.

Methods and results

A 2008 survey on CVD risk factors was linked to cause of death data collected between 2008 and 2018. Cox proportional hazards on relative risk of dying from CVD over a 10-year period following the assessment of cardiovascular disease risk factors were computed. Population attributable fraction (PAF) of incident CVD death was estimated for key risk factors. In total, 4,290 individuals, 44.0% female, mean age 48.4 years in 2008 were included in the analysis. Diabetes and hypertension were 7.8% and 24.9% respectively in 2008. Of 385 deaths recorded between 2008 and 2018, 101 (26%) were caused by CVD. Age (hazard ratio (HR) 1.11; 95% confidence interval (CI) 1.03-1.20, p = 0.005) and hypertension (HR 2.19, 95% CI 1.44-3.33, p <0.001) were positively associated with CVD mortality. Primary school education and higher (HR 0.57, 95% CI 0.33-0.99, p = 0.044) and formal employment (HR 0.22, 95% CI 0.06-0.75, p = 0.015) were negatively associated with CVD mortality. Controlling hypertension would avert 27% (95% CI 9%-42%, p = 0.004) CVD deaths, while if every member of the community attained primary school education and unemployment was eradicated, 39% (95% CI 5% - 60%, p = 0.026), and 17% (95% CI 5%-27%, p = 0.030) of CVD deaths, would be averted respectively.

Conclusions

A holistic approach in addressing socioeconomic factors in the broader context of social determinants of health at the policy, population and individual level will enhance prevention and treatment-adherence for CVD in underserved settings.

Socioeconomic status and cardiovascular risk factors in young adults: a cross-sectional analysis of a Brazilian birth cohort

INTRODUCTION

In high-income countries, persons of high socioeconomic status (SES) have a lower cardiovascular risk. However, in middle and low-income countries, the results are controversial.

OBJECTIVE

To evaluate the association between family income and cardiovascular risk factors in young adults.

METHODS

A total of 2,063 individuals of a birth cohort initiated in 1978/79 in the city of Ribeirão Preto, Brazil, were evaluated at age of 23/25 years. Cardiovascular risk factors (hypertension, sedentary lifestyle, smoking, low high-density lipoprotein (HDL)-cholesterol, high low-density lipoprotein (LDL)-cholesterol, high fibrinogen, insulin resistance, diabetes, abdominal and total obesity, and metabolic syndrome) were evaluated according to family income. Income was assessed in multiples of the minimum wage. Simple Poisson regression models were used to estimate the prevalence ratios (PR) with robust estimation of the variance.

RESULTS

High-income women showed lower prevalences of low HDL-cholesterol (PR = 0.47), total obesity (PR = 0.22), abdominal obesity (PR = 0.28), high blood pressure (PR = 0.28), insulin resistance (PR = 0.57), sedentary lifestyle (PR = 0.47), metabolic syndrome (PR = 0.24), and high caloric intake (PR = 0.71) (p < 0.05). High-income men showed lower prevalences of low HDL-cholesterol (PR = 0.73) and sedentarism (PR = 0.81) (p < 0.05). These results may be explained by the fact that high-income women pay more attention to healthy habits and those with the lowest family income are least likely to access health services resources and treatments.

CONCLUSION

Women were in the final phase of the epidemiologic transition, whereas men were in the middle phase.

Cardiovascular disease risk and its determinants in people living with HIV across different settings in South Africa

Objectives

Socio‐economic factors and lifestyle are known to differ across geographies and populations, which may result in distinct risk profiles for cardiovascular disease (CVD). This study assessed carotid intima‐media thickness (CIMT), a proxy for CVD, and its determinants in two groups of people living with HIV (PLHIV) in two different settings in South Africa.

Methods

A cross‐sectional analysis was conducted comparing data from the Ndlovu Cohort Study in the Limpopo Province (group 1) and from three clinical trials in Johannesburg (group 2). The association between demographics, conventional CVD risk factors, HIV‐related factors and CIMT in groups 1 and 2 was analysed with two separate multivariable linear regression models.

Results

Group 1 consisted of 826 participants (mean age 42.2 years) and mean (± standard deviation) CIMT was 0.626 ± 0.128 mm. In this group, sex, age, body mass index (BMI), cholesterol, glucose and antiretroviral therapy (ART) duration (β = 0.011 mm per 5 years; P = 0.02) were associated with higher CIMT. There were positive interactions between age and ART duration and age and cholesterol. Group 2 consisted of 382 participants (mean age 39.5 years) and mean (± standard deviation) CIMT was 0.560 ± 0.092 mm. In this group, only sex, education level, BMI and cholesterol were associated with higher CIMT, albeit with weaker associations than in group 1.

Conclusions

Conventional CVD risk factors were the main drivers of CIMT. The impact of some of these risk factors appeared to increase with age. Differences in sample size, age and viral suppression might explain why an effect of ART was observed in group 1 but not in group 2.

Quality of life, physical activity and cardiorespiratory fitness in black African women: B-Healthy project

PURPOSE

To study the associations between physical activity (PA), cardiorespiratory fitness (CRF), and health-related quality of life (HRQoL) in black African women from a low socioeconomic community in South Africa.

METHODS

Black African women (n = 146) aged 35-75 years from a low socioeconomic community in South Africa participated in this study. We measured PA levels via ActiHeart® accelerometers, and CRF by measuring peak oxygen consumption (V̇O₂ peak). HRQoL was assessed once with the SF-8 Health Survey (SF-8). Participants were classified into groups based on age, moderate to vigorous PA (MVPA), and V̇O₂ peak. Logistic regressions were used to compare the odds of having total HRQoL component scores above reported norms across PA and fitness groups. Two multiple linear regression models were developed using physical component summary (PCS) and mental component summary (MCS) as response variables respectively.

RESULTS

V̇O₂ peak and MVPA varied considerably across the sample and declined with increasing age. Participants in higher quartiles of MVPA and CRF showed trends to higher PCS scores. For CRF these trends were statistically significant, and persisted after adjustment for age and other possible confounders (p = 0.036). PCS was significantly associated with age, relative V̇O₂ peak, and income (all p < 0.05), while MCS was associated with income (p = 0.028).

CONCLUSIONS

CRF is the most significant predictor, together with age and income, on the PCS of the HRQoL among black African women. We recommend that when seeking improvements in HRQoL, interventions should focus on improving CRF, particularly V̇O₂ peak.

Body composition and physical activity as mediators in the relationship between socioeconomic status and blood pressure in young South African women: a structural equation model analysis

OBJECTIVES

Varying hypertension prevalence across different socioeconomic strata within a population has been well reported. However, the causal factors and pathways across different settings are less clear, especially in sub-Saharan Africa. Therefore, this study aimed to compare blood pressure (BP) levels and investigate the extent to which socioeconomic status (SES) is associated with BP, in rural and urban South Africa women.

SETTING

Rural and urban South Africa.

DESIGN

Cross-sectional.

PARTICIPANTS

Cross-sectional data on SES, total moderate and vigorous physical activity (MVPA), anthropometric and BP were collected on rural (n=509) and urban (n=510) young black women (18-23 years age). Pregnant and mentally or physically disabled women were excluded from the study.

RESULTS

The prevalence of combined overweight and obesity (46.5% vs 38.8%) and elevated BP (27.0% vs 9.3%) was higher in urban than rural women, respectively. Results from the structural equation modelling showed significant direct positive effects of body mass index (BMI) on systolic BP (SBP) in rural, urban and pooled datasets. Negative direct effects of SES on SBP and positive total effects of SES on SBP were observed in the rural and pooled datasets, respectively. In rural young women, SES had direct positive effects on BMI and was negatively associated with MVPA in urban and pooled analyses. BMI mediated the positive total effects association between SES and SBP in pooled analyses (ß 0.46; 95% CI 0.15 to 0.76).

CONCLUSIONS

Though South Africa is undergoing nutritional and epidemiological transitions, the prevalence of elevated BP still varies between rural and urban young women. The association between SES and SBP varies considerably in economically diverse populations with BMI being the most significant mediator. There is a need to tailor prevention strategies to take into account optimising BMI when designing strategies to reduce future risk of hypertension in young women.

Factors Associated with Pre-Hypertension Among Tehranian Adults: A Novel Application of Structural Equation Models

BACKGROUND

Pre-hypertension is proposed as an independent risk factor for the incidence of cardiovascular diseases.

OBJECTIVES

This study aimed to explore the main factors associated with pre-hypertension via testing a hypothesized model in Tehranian adults.

METHODS

The study was conducted within the framework of the Tehran Lipid and Glucose Study (TLGS) between 2009 - 2011 on 4640 adults without hypertension, aged ≥ 20 years.

RESULTS

The mean age of participants was 38.61 ± 12.14 years and 56.6% of them were female. More than one third of the studied participants had pre-hypertension (35.4%) with significantly higher prevalence in males compared to females (46.5% vs. 26.9%; χ² = 190.7, P < 0.001). Age, waist circumference (WC), and serum triglyceride concentrations (TG) were directly associated with pre-hypertension in both men (β = 0.16, β = 0.25, and β = 0.11, respectively) and women (β = 0.16, β = 0.21 and β = 0.09, respectively). Physical activity, only in men (β = 0.07), and marital status only, in women (β = -0.06), were also directly associated with pre-hypertension. Both healthy and poor dietary patterns showed indirect associations with pre-hypertension in both genders via WC and TG. Higher age and lower education in both genders, being married only in men, and unemployed status only in women, were positively associated with pre-hypertension via behavioral and cardio-metabolic factors.

CONCLUSIONS

Level of TG and WC in both genders are direct modifiable associated factors of pre-hypertension. These findings could be considered in designing future health promotion programs aimed at preventing high blood pressure and its consequences among Tehranian adults.

Different adiposity indices and their association with blood pressure and hypertension in middle-aged urban black South African men and women: findings from the AWI-GEN South African Soweto Site

Background

To report associations between different adiposity indices [anthropometric and dual-energy X-ray absorptiometry (DXA) measures] and blood pressure (BP) and hypertension in urban black South African adults.

Methods

Anthropometric and DXA whole body measures were performed on 1026 men and 982 women. Participants were classified as being hypertensive if they had a systolic BP (SBP) ≥ 140 mmHg and/or diastolic (DBP) ≥ 90 mmHg. Within each gender the relationship of adiposity with BP and hypertension risk was assessed using linear and logistic regression models respectively. Bivariate models were computed for each body composition variable. Furthermore, we computed a multiple regression model to illustrates how body composition parameters are associated with the outcome variables independent of each other.

Results

The males were significantly taller and had a higher fat free soft tissue mass (FFSTM), DBP and socio-economic status, and were more likely to use tobacco and be hypertensive (48.0% vs. 38.8%). The females had higher body mass index (BMI), waist circumference (WC), fat mass (FM), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), FM/FFSTM ratio and body fat % than males. All body composition parameters were positively associated with hypertension. In both males and females, the FM/FFSTM ratio associated the strongest with hypertension illustrating the following odds ratios [males: 70.37 (18.47, 268.16) p ≤ 0.001; females 2.48 (0.86,7.21) p = 0.09]. The multiple regression model, indicated that the VAT and WC significantly associated with both SBP and DBP in the men and women respectively, whilst WC was the only significant predictor for hypertension.

Conclusions

All body composition parameters were associated with hypertension and FM/FFSTM ratio showed the strongest relationship. It was reassuring that WC remains a useful measure of central adiposity that can be used as a risk indicator for hypertension if more sophisticated measures are not available. Furthermore, our data in part, implies that reducing abdominal adiposity in aging adults could contribute to reducing the risk of elevated blood pressure and hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5443-4) contains supplementary material, which is available to authorized users.

How does the association of general and central adiposity with glycaemia and blood pressure differ by gender and area of residence in a Malawian population: a cross-sectional study

BACKGROUND

In high-income settings, body mass index (BMI) and measures of central adiposity, such as waist-to-hip ratio (WHR) are associated with cardiometabolic risk, but evidence from low-income settings, particularly sub-Saharan Africa (SSA), is limited. We assessed whether there are differences between central and general adiposity in their associations with fasting glucose, diabetes, systolic and diastolic blood pressures and hypertension, and whether these associations differ with gender or rural/urban setting in Malawi.

METHODS

We used data from a population-based study of 27 880 Malawian adults aged  ≥18 years, from both rural and urban areas. We used age-standardized z-scores of the means of BMI and WHR to directly compare their associations with glycaemic and blood pressure outcomes.

RESULTS

Mean fasting glucose and blood pressure values and odds of hypertension increased linearly across fifths of BMI and WHR, with stronger associations with BMI. For both BMI and WHR, the associations with outcomes were stronger in urban versus rural residents. The association with diabetes was stronger in women than men, whereas for blood-pressure related outcomes a stronger association was seen in men.

CONCLUSIONS

BMI is more strongly associated with cardiometabolic risk in SSA, and might be a more useful measure than WHR, in this population. The greater positive association of adiposity with cardiometabolic outcomes in urban residents (where rates of overweight/obesity are already high) highlights the particular importance of addressing obesity within urban SSA populations.

Economic growth and obesity in South African adults: an ecological analysis between 1994 and 2014

Background

To assess the trend associations between South Africa's economic growth using various economic growth indicators (EGIs) with adult obesity prevalence over a specified period of time. Data for obesity levels reported were obtained from national surveys conducted in South African adults in 1998, 2003 and 2012. EGIs incorporated in the current analysis were obtained from the World Bank and IHS Global insight databases. Obesity prevalence is presented by gender, urbanisation level and ethnicity. EGIs congruent to the time points where obesity data are available are presented. Unadjusted time trend plots were applied to assess associations between obesity prevalence and EGIs by gender, urbanisation level and ethnicity. Females present higher levels of obesity relative to males for all time points. For both males and females, an overall increase in prevalence was observed in both rural and urban settings over-time, with urban dwellers presenting higher obesity levels. An overall increase in Gross Domestic Product (GDP) per capita and Household Final Consumption Expenditure (HFCE) per capita was observed. The Gini coefficient for all ethnicities except the White population increased between 1998 and 2003 but declined by 2012. Overtime per capita GDP and HFCE increased with increasing obesity prevalence in both genders. The trend association between the Gini coefficient for all ethnicities and obesity prevalence was similar for both genders in that as the Gini coefficient increased obesity prevalence declined, and when the coefficient decreased obesity prevalence increased. Trend associations exist between South Africa's economic growth and adult obesity.

Disparities in Management of Cardiovascular Disease in Rural South Africa: Data From the HAALSI Study (Health and Aging in Africa: Longitudinal Studies of International Network for the Demographic Evaluation of Populations and Their Health Communities)

BACKGROUND

Optimal secondary prevention is critical for the reduction of repeated cardiovascular events, and the control of cardiovascular risk factors in this context is essential. Data on secondary prevention of cardiovascular disease (CVD) in sub-Saharan Africa are needed to inform intervention strategies with a particular focus on local disparities. The aim of this study was to assess CVD management in a rural community in northeast South Africa.

METHODS AND RESULTS

We recruited adults aged ≥40 years residing in the Agincourt subdistrict of Mpumalanga province. Data collection included socioeconomic and clinical data, anthropometric measures, blood pressure, human immunodeficiency virus status, and point-of-care glucose and lipid levels. CVD was defined as self-report of myocardial infarction and stroke or angina diagnosed by Rose Criteria. A linear regression model was built to identify variables independently associated with the number of cardiovascular risk factors controlled. Of 5059 subjects, 592 (11.7%) met CVD diagnostic criteria. Angina was reported in 77.0% of these subjects, stroke in 25.2%, and myocardial infarction in 3.7%. Percent controlled of the 5 individual risk factors assessed were as follows: tobacco 92.9%; blood pressure 51.2%; body mass index 33.8%; low-density lipoprotein 31.4%; and waist-to-hip ratio 29.7%. Only 4.4% had all 5 risk factors controlled and 42.4% had ≥3 risk factors controlled. Male sex (β coefficient=0.44; 95% confidence interval, 0.25-0.63; P<0.001), absence of physical disability (β coefficient=0.40; 95% confidence interval, 0.16-0.65; P=0.001), and socioeconomic status (β coefficient=0.10; 95% confidence interval, 0.01-0.19; P=0.035) were directly associated with the number of risk factors controlled.

CONCLUSIONS

Currently, CVD is not being optimally managed in this rural area of South Africa. There are significant disparities in control of CVD risk factors by sex, socioeconomic status, and level of disability. Efforts to improve secondary prevention in this population should be focused on females, subjects from lower socioeconomic status, and those with physical disabilities.

Micronutrient Status and Dietary Intake of Iron, Vitamin A, Iodine, Folate and Zinc in Women of Reproductive Age and Pregnant Women in Ethiopia, Kenya, Nigeria and South Africa: A Systematic Review of Data from 2005 to 2015

A systematic review was conducted to evaluate the status and intake of iron, vitamin A, iodine, folate and zinc in women of reproductive age (WRA) (≥15–49 years) and pregnant women (PW) in Ethiopia, Kenya, Nigeria and South Africa. National and subnational data published between 2005 and 2015 were searched via Medline, Scopus and national public health websites. Per micronutrient, relevant data were pooled into an average prevalence of deficiency, weighted by sample size (WAVG). Inadequate intakes were estimated from mean (SD) intakes. This review included 65 surveys and studies from Ethiopia (21), Kenya (11), Nigeria (21) and South Africa (12). In WRA, WAVG prevalence of anaemia ranged from 18–51%, iron deficiency 9–18%, and iron deficiency anaemia at 10%. In PW, the prevalence was higher, and ranged from 32–62%, 19–61%, and 9–47%, respectively. In WRA, prevalence of vitamin A, iodine, zinc and folate deficiencies ranged from 4–22%, 22–55%, 34% and 46%, while in PW these ranged from 21–48%, 87%, 46–76% and 3–12% respectively. Inadequate intakes of these micronutrients are high and corresponded with the prevalence figures. Our findings indicate that nationally representative data are needed to guide the development of nutrition interventions and public health programs, such as dietary diversification, micronutrient fortification and supplementation.

How dietary intake has been assessed in African countries? A systematic review

BACKGROUND

Dietary patterns are often considered as one of the main causes of non-communicable diseases worldwide. It is of utmost importance to study dietary habits in developing countries since this work is scarce.

OBJECTIVE

To summarize the most recent research conducted in this field in African countries, namely the most used methodologies and tools.

METHODS

A systematic review was conducted on MEDLINE®/PubMed, aiming to identify scientific publications focused on studies of dietary intake of different African populations, in a ten-year period. Papers not written in English/Portuguese/Spanish, studies developed among African people but not developed in African countries, studies aiming to assess a particular nutrient/specific food/food toxin and studies that assessed dietary intake among children were excluded.

FINDINGS

Out of 99 included studies, the 24-hour recall and the food-frequency questionnaire were the most used dietary intake assessment tools, used to assess diet at an individual level. It was also observed that often country-unspecific food composition databases are used, and the methodologies employed are poorly validated and standardized.

CONCLUSIONS

There is an emergent need to improve the existing food databases by updating food data and to develop suitable country-specific databases for those that do not have their own food composition table.

Inventory on the dietary assessment tools available and needed in africa: a prerequisite for setting up a common methodological research infrastructure for nutritional surveillance, research, and prevention of diet-related non-communicable diseases

OBJECTIVE

To carry out an inventory on the availability, challenges, and needs of dietary assessment (DA) methods in Africa as a pre-requisite to provide evidence, and set directions (strategies) for implementing common dietary methods and support web-research infrastructure across countries.

METHODS

The inventory was performed within the framework of the "Africa's Study on Physical Activity and Dietary Assessment Methods" (AS-PADAM) project. It involves international institutional and African networks. An inventory questionnaire was developed and disseminated through the networks. Eighteen countries responded to the dietary inventory questionnaire.

RESULTS

Various DA tools were reported in Africa; 24-Hour Dietary Recall and Food Frequency Questionnaire were the most commonly used tools. Few tools were validated and tested for reliability. Face-to-face interview was the common method of administration. No computerized software or other new (web) technologies were reported. No tools were standardized across countries.

CONCLUSIONS

The lack of comparable DA methods across represented countries is a major obstacle to implement comprehensive and joint nutrition-related programmes for surveillance, programme evaluation, research, and prevention. There is a need to develop new or adapt existing DA methods across countries by employing related research infrastructure that has been validated and standardized in other settings, with the view to standardizing methods for wider use.

Cardiovascular disease in Africa: epidemiological profile and challenges

From a global perspective, the large and diverse African population is disproportionately affected by cardiovascular disease (CVD). The historical balance between communicable and noncommunicable pathways to CVD in different African regions is dependent on external factors over the life course and at a societal level. The future risk of noncommunicable forms of CVD (predominantly driven by increased rates of hypertension, smoking, and obesity) is a growing public health concern. The incidence of previously rare forms of CVD such as coronary artery disease will increase, in concert with historically prevalent forms of disease, such as rheumatic heart disease, that are yet to be optimally prevented or treated. The success of any strategies designed to reduce the evolving and increasing burden of CVD across the heterogeneous communities living on the African continent will be dependent upon accurate and up-to-date epidemiological data on the cardiovascular profile of every major populace and region. In this Review, we provide a contemporary picture of the epidemiology of CVD in Africa, highlight key regional discrepancies among populations, and emphasize what is currently known and, more importantly, what is still unknown about the CVD burden among the >1 billion people living on the continent.

Perceptions of diet, physical activity, and obesity-related health among black daughter-mother pairs in Soweto, South Africa: a qualitative study

BACKGROUND

The prevalence of overweight and obesity is on the rise in South Africa, particularly among females living in urban environments. The purpose of this qualitative study was to explore the emic perspectives of black young adult daughter and mother pairs living in Soweto, South Africa on diet, physical activity, and obesity-related health within their social and cultural context.

METHODS

Purposeful sampling was used to recruit daughters with a normal body mass index (BMI) who have obese mothers. Individual semi-structured in-depth interviews were conducted with 17 daughters (age 24 years) and 15 of their mothers in Soweto, South Africa. Interview questions related to: a) eating and physical activity behaviors and perceptions, b) perceptions of social and community level factors, c) cultural beliefs about diet and body image, and d) intergenerational relationships. Data were analyzed using four-phases of thematic analysis and the constant comparison approach.

RESULTS

Daughters and mothers had similar ideas of the definition of healthy food and the importance of eating healthy, but mothers were more likely to report eating healthy because of their age, adverse health experiences, and a desire to live longer. Daughters and mothers engaged in physical activity for reasons related to weight maintenance and feeling better, but mothers reported being more likely to start exercising as a result of a health concern. Daughters and mothers had comparable views of what makes a person healthy. Daughters and mothers relied on each other for food purchasing and food preparation.

CONCLUSION

Daughters and mothers shared some similar perceptions of diet, physical activity, and health that were rooted in their daily life in Soweto. However, mothers generally reported being more likely to exhibit healthy eating and physical activity behaviors despite being obese. The mothers may have adopted these perceptions and behaviors later in life linked to ageing and ill-health. It is possible that through exposure, their daughters have assimilated these perceptions earlier in childhood or adolescence. It is important to focus health promotion efforts around preventing the otherwise expected increase of obesity among the young adult generation.

Dietary Intake of the Urban Black Population of Cape Town: The Cardiovascular Risk in Black South Africans (CRIBSA) Study

INTRODUCTION

To determine dietary intake of 19 to 64 years old urban Africans in Cape Town in 2009 and examine the changes between 1990 and 2009.

METHODS

A representative cross-sectional sample (n = 544), stratified by gender and age was randomly selected in 2009 from the same areas sampled in 1990. Socio-demographic data and a 24-h dietary recall were obtained by trained field workers. The associations of dietary data with an asset index and degree of urbanization were assessed.

RESULTS

Fat intakes were higher in 19-44-year-old men (32% energy (E)) and women (33.4%E) in 2009 compared with 1990 (men: 25.9%E, women: 27.0%E) while carbohydrate intakes were lower in 2009 (men 53.2%E, women: 55.5%E) than in 1990 (men: 61.3%E; women: 62%E) while sugar intake increased significantly (p < 0.01) in women. There were significant positive correlations between urbanization and total fat (p = 0.016), saturated fat (p = 0.001), monounsaturated fat (p = 0.002) and fat as a %E intake (p = 0.046). Urbanization was inversely associated with intake of carbohydrate %E (p < 0.001). Overall micronutrient intakes improved significantly compared with 1990. It should also be noted that energy and macronutrient intakes were all significant in a linear regression model using mean adequacy ratio (MAR) as a measure of dietary quality in 2009, as was duration of urbanization.

DISCUSSION

The higher fat and lower carbohydrate %E intakes in this population demonstrate a transition to a more urbanized diet over last two decades. These dietary changes reflect the nutrition transitions that typically occur as a longer time is spent in urban centers.

Nutrient patterns and their association with socio-demographic, lifestyle factors and obesity risk in rural South African adolescents

The aim of this study was to identify and describe the diversity of nutrient patterns and how they associate with socio-demographic and lifestyle factors including body mass index in rural black South African adolescents. Nutrient patterns were identified from quantified food frequency questionnaires (QFFQ) in 388 rural South African adolescents between the ages of 11-15 years from the Agincourt Health and Socio-demographic Surveillance System (AHDSS). Principle Component Analysis (PCA) was applied to 25 nutrients derived from QFFQs. Multiple linear regression and partial R2 models were fitted and computed respectively for each of the retained principal component (PC) scores on socio-demographic and lifestyle characteristics including body mass index (BMI) for age Z scores. Four nutrient patterns explaining 79% of the total variance were identified: PCI (26%) was characterized by animal derived nutrients; PC2 (21%) by vitamins, fibre and vegetable oil nutrients; PC3 (19%) by both animal and plant derived nutrients (mixed diet driven nutrients); and PC4 (13%) by starch and folate. A positive and significant association was observed with BMI for age Z scores per 1 standard deviation (SD) increase in PC1 (0.13 (0.02; 0.24); p = 0.02) and PC4 (0.10 (-0.01; 0.21); p = 0.05) scores only. We confirmed variability in nutrient patterns that were significantly associated with various lifestyle factors including obesity.

Low BMI is inversely associated with arterial stiffness in Africans

In low socio-economic status communities in South Africa, African men showed a low BMI. Data on the effect of low BMI on cardiovascular function are scant. The present study aimed to assess the associations between low BMI and markers of cardiovascular function such as pulse wave velocity (PWV) and blood pressure in Africans aged 35-65 years, with low socio-economic status. The study population (n 496) was stratified into a low-BMI group with BMI ≤ 20 kg/m² and a normal-BMI group with BMI >20 kg/m² and ≤ 25 kg/m². Blood pressure (Omron HEM-757) and PWV (Complior SP; Artech-Medical) was determined. Africans with low BMI showed an increased arterial stiffness with significantly higher PWV compared with the normal-BMI group (men: P= 0.001; women: P= 0.026), which remained after adjustment. In men with low BMI, PWV correlated negatively with BMI before (r -0.204; P= 0.012) and after (r -0.200; P= 0.020) adjustment. Forward stepwise regression analyses indicated a negative association between PWV and BMI in African men. A J-curve was evident suggesting a detrimental effect of low BMI on cardiovascular function in Africans. A low BMI may contribute to the high prevalence of cardiovascular-related morbidity and mortality within a developing country.

Model-based patterns of cardiovascular risk factors in Mozambique

BACKGROUND

Risk factors for cardiovascular diseases tend to cluster, although evidence from settings under epidemiological transition is scarce.

AIM

To identify patterns of clustering of cardiovascular risk factors and to quantify their association with sociodemographic characteristics, in Mozambique.

SUBJECTS AND METHODS

A national representative sample (n = 3323) of subjects aged 25-64 years was evaluated in 2005, using the World Health Organization Stepwise Approach to Chronic Disease Risk Factor Surveillance (STEPS). Patterns of joint exposure to high blood pressure, high fasting blood glucose, high body mass index, smoking, excessive alcohol consumption, low fruit/vegetables intake and insufficient physical activity were identified through latent class analysis.

RESULTS

Three patterns were identified among women: (1) "healthier", lower frequency of most risk factors (53.0%); (2) "hypertension-overweight" (21.1%), more frequent among older and urban subjects; and (3) "hypertension-smoking-alcohol" (25.9%), whose frequency increased with age and decreased with education. In men, two clusters were identified: (1) "hypertension-overweight" (30.1%); and (2) "smoking" (69.9%). The frequency of the latter pattern was higher in urban areas and increased with age and education.

CONCLUSION

Hypertension, overweight/obesity, smoking and excessive alcohol intake defined the main clusters of cardiovascular risk factors. This should be considered when planning prevention and control strategies for cardiovascular diseases in Mozambique.

Associations of suPAR with lifestyle and cardiometabolic risk factors

BACKGROUND

Soluble urokinase plasminogen activator receptor (suPAR), a novel indicator of low-grade inflammation, is associated with cardiovascular disease and mortality in the general population, while an unhealthy lifestyle influences inflammatory status. We aimed to explore the relationship of suPAR with lifestyle and cardiometabolic risk factors in a black South African population.

DESIGN

This cross-sectional study includes 1068 men and women (56·4 ± 10·1 years) from the North West province who took part in the South African leg of the Prospective Urban and Rural Epidemiology (PURE) study in 2010. Captured data included a detailed lifestyle profile (tobacco use, alcohol consumption, physical activity, psychological and dietary intake status), biochemical analyses (suPAR, C-reactive protein (CRP), glucose and lipids), as well as cardiovascular and anthropometric measurements.

RESULTS

In exploratory analyses, we observed positive relationships between suPAR and lifestyle factors, such as tobacco use (P-trend < 0·001), both alcohol consumption (P-trend = 0·001) and γ-glutamyl transferase (GGT) (P-trend < 0·001) and unemployment (P-trend = 0·002). suPAR and CRP correlated significantly (r = 0·23; P < 0·001). These relationships were confirmed in multiple regression analyses as suPAR independently associated with tobacco use (β = 0·13; P < 0·001), GGT (β = 0·24; P < 0·001) and unemployment (β = 0·07; P = 0·039). suPAR did not associate with the cardiometabolic factors glucose, lipids, blood pressure or measures of adiposity.

CONCLUSION

suPAR was independently associated with unhealthy lifestyle behaviours, but not with cardiometabolic risk factors suggesting that suPAR, as known predictor of cardiovascular disease and mortality, is augmented by modifiable cardiovascular risk factors. These findings emphasise the need for a healthy lifestyle to decrease the burden of cardiovascular disease in Africans.