Anthropometric nutritional status of children (0-18 years) in South Africa 1997-2022: a systematic review and meta-analysis.

OBJECTIVE: To conduct a comprehensive systematic review and meta-analysis of the available literature on the anthropometric nutritional status of South African infants and children, 0-18 years old and to report on trends of changes in nutritional status over the period 1997-2022. DESIGN: Systematic review and meta-analysis. SETTING: Review of the available literature on the anthropometric nutritional status of South African infants and children, 0-18 years old, over the period 1997-2022. PARTICIPANTS: South African infants and children, 0-18 years old. RESULTS: Only quantitative data from ninety-five publications that described the nutritional status in terms of anthropometry were included. Most recent studies applied the WHO 2006 and 2007 definitions for malnutrition among children 0-5 years old and 5-19 years old, respectively. Meta-analysis of all prevalence data shows the highest stunting prevalence of 25·1 % among infants and preschool children, compared to 11·3 % among primary school-age children and 9·6 % among adolescents. Furthermore, the overweight and obesity prevalence was similar among children younger than 6 years and adolescents (19 %), compared to 12·5 % among primary school-age children. In national surveys, adolescent overweight prevalence increased from 16·9 % in 2002 to 23·1 % in 2011. Meta-regression analysis shows a decrease in stunting among children 6-18 years old and an increase in combined overweight and obesity in the 10-19 years age group. CONCLUSION: The double burden of malnutrition remains evident in South Africa with stunting and overweight/obesity the most prevalent forms of malnutrition among children.

Differences in calculated body fat percentage estimated from published equations based on bioelectric impedance analysis in healthy young South African adults.

Background: Adult overweight and obesity, in addition to the intake of saturated fat and total serum cholesterol must be monitored as biological risk factors for non-communicable diseases (NCDs). Bioelectric impedance analysis (BIA) provides data on body fat for use in epidemiological settings. However, optimized equations should be used to calculate percentage body fat (%BF). The purpose of this study was to assess the differences between %BF calculated using different published BIA equations and %BF measured by BIA in young South African adults. Design and methods: In this observational study, differences in calculated %BF were assessed, with different BIA equations retrieved from the literature used in 1128 healthy young adults aged 20-30 years. The %BF (measured by BIA) was compared between equations, between Black and White men and women, respectively. Results: The results showed statistically significant differences in the %BF calculated from published BIA equations when used in young South African adults (χ² = 946, χ² = 2528, χ² = 2088, respectively, p < 0.0001). In Black and White men and women, respectively, %BF levels were significantly higher when calculated by equations, than when measured by BIA (p < 0.0001). Conclusion: There seem to be large discrepancies in estimating %BF by BIA equations and these values cannot be used interchangeably for young South African adults. A South African age, ethnicity and sex-specific BIA equation needs to be developed to accurately estimate %BF in young South African adults.

Birth Weight and Body Composition as Determined by Isotopic Dilution with Deuterium Oxide in 6- to 8-Year-Old South African Children.

Low and high birth weight (BW) are associated with obesity later in life; however, this association has not been extensively studied in African countries. This study determines the association between BW and body composition derived from deuterium oxide (D2O) dilution in 6- to 8-year-old South African children (n = 91; 40 boys, 51 girls). BW was recorded retrospectively from the children's Road-to-Health cards. Weight and height were measured using standard procedures, and D2O dilution was used to determine total body water and, subsequently, to determine body fat. Fatness was classified using the McCarthy centiles, set at 2nd, 85th, and 95th (underfat, overfat and obese). BW correlated with body composition measures, such as body weight (r = 0.23, p = 0.03), height (r = 0.33, p < 0.001), and fat free mass (FFM; r = 0.27, p = 0.01). When multiple regression analysis was employed, BW significantly and positively associated with FFM (ß = 0.24, p = 0.013; 95% CI: 0.032; 0.441) and fat mass (ß = 0.21, p = 0.02, 95%CI: 0.001; 0.412) in girls and boys combined. A total of 13% of the children had a low BW, with 21% being overweight and 17% obese. More girls than boys were overweight and obese. Intervention strategies that promote healthy uterine growth for optimal BW are needed in order to curb the global obesity pandemic.

The Metabolic Profiles of Metabolically Healthy Obese and Metabolically Unhealthy Obese South African Adults over 10 Years.

Obesity is associated with an increased cardiometabolic risk, but some individuals maintain metabolically healthy obesity (MHO). The aims were to follow a cohort of black South African adults over a period of 10 years to determine the proportion of the group that maintained MHO over 10 years, and to compare the metabolic profiles of the metabolically healthy and metabolically unhealthy groups after the follow-up period. The participants were South African men (n = 275) and women (n = 642) from the North West province. The prevalence of obesity and the metabolic syndrome increased significantly. About half of the metabolically healthy obese (MHO) adults maintained MHO over 10 years, while 46% of the women and 43% of men became metabolically unhealthy overweight/obese (MUO) at the end of the study. The metabolic profiles of these MHO adults were similar to those of the metabolically healthy normal weight (MHNW) group in terms of most metabolic syndrome criteria, but they were more insulin resistant; their CRP, fibrinogen, and PAI-1act were higher and HDL-cholesterol was lower than the MHNW group. Although the metabolic profiles of the MUO group were less favourable than those of their counterparts, MHO is a transient state and is associated with increased cardiometabolic risk.

A demographic approach to assess elevated blood pressure and obesity in prepubescent children: the ExAMIN Youth South Africa study.

BACKGROUND: Obesity and hypertension prevalence among children are a concern, with limited evidence available on sex and ethnic differences in childhood blood pressure. We aimed to determine the number of children with hypertension and obesity to identify unique adiposity and blood pressure characteristics by sex and ethnicity, and to estimate the odds of having elevated blood pressure with increasing adiposity. METHODS: We included 1062 healthy children (5-9 years of age) in an observational school-based study in South Africa. Pediatric validated automated devices were used to measure brachial blood pressure and performed pulse wave analysis to assess central hemodynamics. Standard anthropometry was carried out to determine body composition and demographic questionnaires were completed. RESULTS: Almost 20% of children were overweight/obese and 14.1% had elevated blood pressure or hypertension (22.8%). Ethnic differences included greater adiposity in white compared with black children (all P < 0.0001), but higher DBP and total vascular resistance in black compared with white children (both P < 0.05). DBP and total vascular resistance were also higher in girls than boys (both P < 0.01). A 51-60% increased risk of developing elevated blood pressure was observed for 1SD (standard deviation) increase of sex-specific BMI [1.60 (1.4-1.8); P < 0.0001] and waist/height ratio [1.51 (1.3-1.7); P < 0.0001]. CONCLUSION: Unique sex and ethnic differences in body composition and blood pressure exist in prepubescent children, with overweight/obesity increasing the risk of elevated blood pressure. Our findings support primary prevention strategies to combat the growing burden of hypertension and obesity-related diseases in youth. TRIAL REGISTRATION: The study is registered on ClinicalTrials.gov (NCT04056377).

Physical activity, diet and quality of life during mandatory (COVID-19) quarantine following repatriation.

The coronavirus disease 2019 crisis in South Africa has been managed through an effective evidence-based approach. The aim of this case report was to determine the value of staying physically active during the coronavirus disease 2019 pandemic, using online resources to prevent the harmful effects of sedentary behaviour under confined living conditions. A repatriated South African citizen was placed into monitored 14-day quarantine confined to a room, self-monitoring dietary intake and physical and health measures, while engaged in online exercise videos and indoor walking. This study demonstrates that structured indoor activity improves physical and mental health outcomes, despite prolonged sitting time during the day. During the current pandemic and in the presence of limited freedom of movement, sustained physical activity is made feasible by accessing online tools and resources, essentially reducing vulnerability to existing cardiovascular health concerns. However, these findings are based on a single participant and therefore further study is required.

The Exercise, Arterial Modulation and Nutrition in Youth South Africa Study (ExAMIN Youth SA).

Background: The impact of a sedentary and unhealthy lifestyle on cardiovascular health is well-documented, however the current obesity and hypertension trends among children is concerning. The ExAMIN Youth SA study aims to investigate the impact of lifestyle behaviors (physical fitness/activity, dietary intake and psychosocial factors) involved in early vascular aging among South African children. Methods: This study is an analytical, multidisciplinary, observational cohort study in a school-based setting. We aim to phenotype a cohort of ~1,000 primary school children (black and white boys and girls between ages 5-9 years) based on current clinical childhood conditions including hypertension and obesity. The primary phenotype is large artery stiffness and retinal microvascular diameters, both biomarkers of early vascular aging. The risk factors and mediators of early vascular aging and also responsible for the clinical conditions include physical inactivity, unhealthy diet, and life stress. Additionally, urinalysis and salivary analyses will be performed to identify biomarkers related to the pathophysiology of early vascular aging. Discussion: In line with the growing prevalence of obesity and hypertension responsible for the development of early vascular aging from childhood to adulthood, this study will address the critical areas in which we observe unfavorable arterial modulation related to dietary behaviors, physical inactivity, and early life stress. Implementation of novel biological markers may further contribute to our understanding of early cardiovascular adaptations in childhood, and aid in the development of primary prevention programs. Trial registration: The study was retrospectively registered on ClinicalTrials.gov on 15 August 2019 (NCT04056377).

Plasma phospholipid fatty acid patterns are associated with adiposity and the metabolic syndrome in black South Africans: a cross-sectional study.

BACKGROUND: Diets rich in n-6 polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFA) have been associated with increased risk of obesity and the metabolic syndrome (MetS), but the evidence is inconsistent, whereas diets high in n-3 long-chain (LC) -PUFAs are associated with lower risk. There is limited information about the association of plasma phospholipid fatty acids (FAs) with obesity and the MetS among black South Africans. OBJECTIVE: To investigate the association of dietary FAs and plasma phospholipid FA patterns, respectively, with measures of adiposity (body mass index, waist circumference, waist-to-height ratio) and the MetS in black South Africans. METHODS: Factor analysis was used to identify FA patterns from 11 dietary FAs and 26 individual plasma phospholipid FAs. Cross-sectional association of the identified patterns with measures of adiposity and the MetS was investigated. A random sample of 711 black South African adults aged 30 to 70 years (273 men, 438 women) from the North West Province was selected from the South African leg of the Prospective Urban and Rural Epidemiology (PURE) study. Sequential regression models adjusted for confounders were applied to investigate the association between dietary FAs and plasma phospholipid FA patterns with measures of adiposity and the MetS. RESULTS: Two patterns were derived from dietary FAs and six patterns from plasma phospholipid FAs that explained the cumulative variance of 89 and 73%, respectively. The association of FA patterns with adiposity and the MetS was weaker for dietary FA patterns than for plasma phospholipid FA patterns. The plasma phospholipid FA pattern with high loadings of saturated FAs (high-Satfat) and another with high loadings of n-3 very-long-chain PUFAs (n-3 VLC-PUFAs) were positively associated with measures of adiposity and the MetS, while patterns with positive loadings of LC monounsaturated fatty acids (n-9 LC-MUFA) and a positive loading of n-3 essential FAs (n-3 EFA) showed inverse associations with the MetS and some measures of adiposity. CONCLUSION: The n-9 LC-MUFA and n-3 EFA patterns seemed to provide possible protective associations with adiposity and the MetS, whereas the high-Satfat and n-3 VLC-PUFA patterns were associated with adiposity and the MetS in our study participants. The results are reflective of the metabolic difference between overweight and obese compared to lean individuals.

Type of dietary fat intakes in relation to all-cause and cause-specific mortality in US adults: an iso-energetic substitution analysis from the American National Health and Nutrition Examination Survey linked to the US mortality registry.

Accumulating evidence indicates that saturated fat intake is related to mortality risk increase, whereas unsaturated fat intake is associated with reduced mortality risk. The aim of the present study was to estimate the mortality risk reduction related to a dietary change from saturated fat to mono- or polyunsaturated fat intake. The American National Health and Nutrition Examination Surveys conducted between 1999 and 2010 were linked to the 2011 national US death registry resulting in an observational prospective mortality study. Proportional hazards Cox models were used to evaluate the association between saturated, monounsaturated and polyunsaturated fat with all-cause and cause-specific mortality. Substitution analysis was conducted to estimate an iso-energetic substitution of 10 % of the energy from dietary fat intake applied to the substitution of saturated fat with an equal amount of energy from monounsaturated or polyunsaturated fat. The highest tertile intakes of saturated fat resulted in an increased risk (12 %) of all-cause and specific-cause mortality, whereas the highest tertile intakes of polyunsaturated fat resulted in a reduced risk (7 %) of all-cause and specific-cause mortality when compared with the corresponding lowest tertile. Iso-energetic substitution revealed that a substitution of 10 % of energy (from total fat) from saturated fat to an equal amount of energy from monounsaturated or polyunsaturated fat resulted in a significant reduction of the mortality risk ranging from 4 to 8 %. Iso-energetic substitution of saturated fat with monounsaturated and polyunsaturated fat reduced all-cause and specific-cause mortality in US adults.

Association of 25-hydroxyvitamin D and parathyroid hormone with the metabolic syndrome in black South African women.

The relationship between 25 hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and metabolic traits appear to differ among ethnicities and may be influenced by obesity. The aim of the study was to examine the association of serum 25(OH)D or PTH with metabolic syndrome (MetS) while controlling for adiposity in black women. Using a cross-sectional study design, 209 urban black women aged ≥ 43 years from the North West Province, South Africa, were included. Multiple regression models were used to explore the relationship between 25(OH)D or PTH and body composition. To explore the association between 25(OH)D or PTH and MetS, a separate variable was created including at least 3 of the MetS criteria, but excluding elevated waist circumference as a diagnostic criterion in a logistic regression model. The majority of the women (69.9%) were overweight or obese and 65.5% of the women had excessive adiposity using the age-specific cut-off points for body fat percentage. All body composition variables were positively associated with PTH, whereas body mass index and waist circumference, but not body fat percentage, had negative associations with 25(OH)D also after adjusting for confounders. Before and after adjusting for age, body fat, habitual physical activity, tobacco use, season of data collection, and estimated glomerular filtration rate, neither 25(OH)D nor PTH showed significant associations with MetS. Although PTH was positively associated and 25(OH)D was negatively associated with adiposity in black women, there was no association between either 25(OH)D or PTH and MetS in this study population, nor did adiposity influence these relationships.

Disordered Eating Behavior, Body Image, and Energy Status of Female Student Dancers.

BACKGROUND: Modern culture has stereotyped the female body as one that is continually getting thinner. Internalization of the 'thin' ideal is partly attributable to the inner ideal to be successful combined with the external pressure imposed by media and others. Many individuals attempt to achieve these ideals by behavior modification that imposes health risks. PURPOSE: To investigate disordered eating (DE) behavior and energy status in female student dancers. METHODS: Volunteer dancers (n = 26) aged 19.0 (18.0; 21.0) years, matched by controls (n = 26) aged 20.0 (19.0; 21.0) years were recruited. Eating Disorder Inventory-3 (EDI-3) subscales, Three-factor Eating Questionnaire (TFEQ) Cognitive Dietary Restraint (CDR) subscale, and EDI-3 Referral Form behavioral questions assessed DE behavior. Energy status was assessed with a food record and Actiheart monitor. RESULTS: Dancers achieved significantly higher scores than controls in all questionnaires, namely: EDI-3 Drive for Thinness [12.0 (3.0; 19.0) vs. 4.5 (2.0; 9.0), p = .023], EDI-3 Body Dissatisfaction [16.0 (10.0; 25.0) vs. 6.5 (3.0; 14.0), p = .004], and TFEQ-CDR [9.0 (2.0; 15.0) vs. 3.0 (3.0; 7.0), p = .032]; dancers used excessive exercise to lose weight (19.2% vs. 0%, c2 = 5.53, p = .019), and had lower energy availability (24% vs. 8%, p < .05) than controls. The average energy balance (EB) was negative for both groups [dancers: EB = -3896 (-5236; -1222) vs. CONTROLS: EB = -2639 (-4744; -789) kJ/day]. CONCLUSION: Female dancers are at risk for DE behavior and many have suboptimal energy status which may be related to their quest to achieve a more desirable appearance; education on healthy weight management practices is needed.

Stunting, adiposity, and low-grade inflammation in African adolescents from a township high school.

OBJECTIVE: The objective of this study was to compare the inflammatory status of children with differences in nutritional status. METHODS: This was a cross-sectional study of 184 African children aged 13-18 y from a low socioeconomic background that compared stunted with non-stunted and lean with over-fat (percentage of body fat above normal cutoff points) children. Fasting serum tumor necrosis factor-alpha, interleukin-6, C-reactive protein, and insulin were measured using high-sensitivity methods. Body composition was assessed using anthropometry and air-displacement plethysmography. T tests for parametric data and the Mann-Whitney test for non-parametric data were used to compare groups. Regression analyses and principal components analyses were done to assess relations between body composition and biochemical variables. RESULTS: Of all participants 18% were stunted. Serum tumor necrosis factor-alpha of stunted girls was higher than in non-stunted girls. More of the stunted boys were over-fat compared with their non-stunted counterparts. Regression analyses showed that insulin resistance, diastolic blood pressure, and C-reactive protein contributed significantly to interleukin-6 in boys. Serum C-reactive protein, waist circumference, and body mass index clustered together in factor analysis in boys. Serum interleukin-6, waist-hip ratio, and tumor necrosis factor-alpha clustered together in factor analysis in girls. CONCLUSION: An association between adiposity and stunting and between adiposity low-grade inflammation was found in this study. Interventions for stunted children focus mainly on correction of undernutrition by providing feeding schemes. Attention should, however, also be paid to changes in body composition over time to prevent excessive abdominal fat accumulation and risk for cardiovascular diseases later in life.