Body fatness or anthropometry for assessment of unhealthy weight status? Comparison between methods in South African children and adolescents

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.

Longitudinal assessments of child growth: A six-year follow-up of a cluster-randomized maternal education trial

Background & aims

Child growth impairments are rampant in sub-Saharan Africa. To combat this important health problem, long-term follow-up studies are needed to examine possible benefits and sustainability of various interventions designed to correct inadequate child growth. Our aim was to perform a follow-up study of children aged 60−72 months whose mothers participated in a two-armed cluster-randomized education intervention trial lasting 6 months in rural Uganda when their children were 6−8 months old with data collection at 20−24 and at 36 months. The education focused on nutrition, hygiene, and child stimulation.

Methods

We measured growth using anthropometry converted to z-scores according to WHO guidelines. We also included assessments of body composition using bioimpedance. We used multilevel mixed effect linear regression models with maximum likelihood method, unstructured variance-covariance structure, and the cluster as a random effect component to compare data from the intervention (receiving the education and routine health care) with the control group (receiving only routine health care).

Results

Of the 511 children included in the original trial, data from 166/263 (63%) and 141/248 (57%) of the children in the intervention and control group, respectively, were available for the current follow-up study. We found no significant differences in any anthropometrical z-score between the two study groups at child age of 60−72 months, except that children in the intervention group had lower (P = 0.006) weight-for-height z-score than the controls. There were no significant differences in the trajectories of z-scores or height growth velocity (cm/year) from baseline (start of original trial) to child age of 60−72 months. Neither did we detect any significant difference between the intervention and control group regarding body composition (fat mass, fat free mass, and total body water) at child age 60−72 months. Separate gender analyses had no significant impact on any of the growth or body composition findings.

Conclusion

In this long-term study of children participating in a randomized maternal education trial, we found no significant impact of the intervention on anthropometrical z-scores, height growth velocity or body composition.

Trial registration

Clinical Trials (clinical trials.gov) ClinicalTrials.gov ID NCT 02098031.

Complementary feeding practices and their association with adiposity indicators at 12 months of age

Nutrition during the first 1000 days of life represents a window of opportunity to reduce the risk of metabolic dysfunctions later in life. Exclusive breastfeeding (EBF) and adequate introduction of solid foods are essential to promote metabolic and nutritional benefits. We evaluated the association of infant feeding practices from birth to 6 months (M) with adiposity indicators at 12 M. We performed a secondary analysis of 106 healthy term infants born from a cohort of healthy pregnant women. Type of breastfeeding (exclusive or nonexclusive), the start of complementary feeding (CF) (before (<4 M) or after (≥4 M)), and adiposity (body mass index - BMI, body mass index-for-age - BMI/A, waist circumference - WC, and waist circumference-length ratio - WLR) were evaluated at 12 M using descriptive statistics, mean differences, X2, and linear regression models. During the first 6 M, 28.3% (n = 30) of the infants received EBF. Early CF (<4 M) was present in 26.4% (n = 28) of the infants. Children who started CF < 4 M were less breastfed, received added sugars as the most frequently introduced food category, and showed higher BMI, BMI/A, WC, and WLR; those who consumed added sugars early (<4 M) had a higher WC. Starting CF < 4 M was the main factor associated with a higher WC at 12 M. Unhealthy infant feeding practices, such as lack of EBF, early CF, and early introduction of sugars, may be associated with higher adiposity at 12 M.

Comparison of Body Mass Index and fat percentage criteria classification of 7-13 year-old rural boys in South Africa

Background

The aim of this paper was to investigate whether BMI and fat percentage classification criteria, would classify a sample of 7–13 year old boys from a rural background in similar nutritional categories.

Methods

A cross-sectional study with a stratified random sampling included 601 rural boys (7–13 years old). Fat percentage criteria classification and BMI were calculated and compared. Maturity status, and age at peak height velocity (PHV) were indirectly determined. Statistical techniques included descriptive statistics, Pearson product correlation coefficients, the Kappa agreement test and the McNemar’s test. The level of statistical significance was set at p ≤ 0.05.

Results

All age groups presented with statistically significant high correlations between BMI and fat percentage, and low to medium correlations between fat percentage and maturity age (MA). Measurement of agreement between BMI and fat percentage classifications showed poor to fair agreements for all age groups, with the exception of the eight-year old group which presented a moderate agreement.

Conclusions

Classifications based on BMI and fat percentage, results in different classifications for the same population. Until further research has been done to determine the best classification for nutritional status, it is recommended that both classification methods be used for more accurate classification of nutritional status.

Prevalence, incidence, and trends of childhood overweight/obesity in Sub-Saharan Africa: a systematic scoping review

Background

The growing burden of non-communicable diseases (NDC), particularly in low-and middle-income countries, poses a significant threat to global health. Obesity and overweight constitute major risk factors of NCDs such as heart diseases, diabetes, and kidney disease, and as a result, contribute significantly to the development of chronic morbidities, reduced quality of life, and increased risk of premature death. This study described evidence on the prevalence, incidence, and trends of childhood overweight and obesity in sub-Sahara Africa (SSA).

Methods

We conducted a systematic scoping review employing the Arksey and O’Malley framework, Levac et al. recommendations, and the Joanna Briggs Institute guidelines. To obtain relevant published articles for this review, we performed a comprehensive keywords search in PubMed, Google Scholar, Web of Science, and CINAHL via EBSCOhost platform for studies published between 2009 and June 2019. Guided by the eligibility criteria, title and abstracts, as well as the full-text articles were independently screened in parallel by two investigators. All relevant data were independently extracted by two investigators using a piloted form designed in Microsoft and thematic analysis conducted.

Results

Of the 81 included studies obtained from 250,148 potentially eligible articles, the majority (25) conducted in South Africa followed by 18 in Nigeria. Six studies were conducted in Ethiopia (6), Tanzania (5), Kenya (4), Cameroon (4), Ghana (3), Uganda (2), Mozambique (2), and Sudan (2). One study each was conducted in Botswana, Gambia, Lesotho, Mauritius, Seychelles, Togo, and Zimbabwe. The remaining three articles were multi-country studies. Most (81.5%) of the included studies were cross-sectional surveys and the majority (79) focused on both male and female participants. The majority (80/81) of the included studies reported on the prevalence of childhood overweight/obesity, 8 on the trends of childhood overweight/obesity, and one presented evidence on the incidence of childhood overweight and obesity in SSA.

Conclusion

This review demonstrates limited studies on childhood overweight/obesity in most SSA countries although the included studies suggest an increasing burden. Considering the consequences of childhood obesity, there is a need for more primary researches to inform policies decision and implementation to halt the rise of childhood obesity/overweight in SSA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-020-00491-2.

Diagnostic Accuracy of Body Mass Index in Defining Childhood Obesity: Analysis of Cross-Sectional Data from Ghanaian Children

Background: Screening methods for childhood obesity are based largely on the published body mass index (BMI) criteria. Nonetheless, their accuracy in African children is largely unknown. The diagnostic accuracies of the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC), and the International Obesity Taskforce (IOTF) BMI-based criteria in defining obesity using deuterium dilution as a criterion method in a sample of Ghanaian children are presented. Methods: Data on anthropometric indices and percent body fat were collected from 183 children aged 8–11 years. The sensitivity, specificity, and predictive values were calculated. The overall performance of the BMI criteria was evaluated using the receiver operating characteristics area under the curve (AUC). Results: Overall sensitivity of WHO, CDC, and IOTF were 59.4% (40.6–76.3), 53.1% (34.7–70.9), and 46.9% (29.1–65.3) respectively. The overall specificity was high, ranging from 98.7% by WHO to 100.0% by IOTF. The AUC were 0.936 (0.865–1.000), 0.924 (0.852–0.995), and 0.945 (0.879–1.000) by the WHO, CDC, and IOTF criteria respectively for the overall sample. Prevalence of obesity by the WHO, CDC, IOTF, and deuterium oxide-derived percent body fat were 11.5%, 10.4%, 8.2%, and 17.5% respectively, with significant positive correlations between the BMI z-scores and percent body fat. Conclusions: The BMI-based criteria were largely specific but with moderate sensitivity in detecting excess body fat in Ghanaian children. To improve diagnostic accuracy, direct measurement of body fat and other health risk factors should be considered in addition to BMI.

Breastfeeding, HIV exposure, childhood obesity, and prehypertension: A South African cohort study

BACKGROUND

Evidence on the association between breastfeeding and later childhood obesity and blood pressure (BP) is inconsistent, especially in HIV-prevalent areas where, until recently, HIV-infected women were discouraged from breastfeeding, but obesity is increasingly prevalent.

METHODS AND FINDINGS

The Siyakhula cohort (2012-2014), a population-based prospective cohort study, collected data over 3 visits on HIV-negative children ages 7 to 11 years in rural South Africa. We used weight (body mass index [BMI]), fat, and BP as outcome variables and incorporated early life (including mother's age at delivery and HIV status) and current life factors (including maternal education and current BMI). Our primary exposure was breastfeeding duration. We dichotomized 3 outcome measures using pre-established thresholds for clinical interpretability: (1) overfat: ≥85th percentile of body fat; (2) overweight: >1 SD BMI z score; and (3) prehypertension: ≥90th percentile for systolic BP (SBP) or diastolic BP (DBP). We modelled each outcome using multivariable logistic regression, including stopping breastfeeding, then early life, and finally current life factors. Of 1,536 children (mean age = 9.3 years; 872 girls; 664 boys), 7% were overfat, 13.2% overweight, and 9.1% prehypertensive. Over half (60%) of the mothers reported continued breastfeeding for 12+ months. In multivariable analyses, continued breastfeeding between 6 and 11 months was associated with approximately halved odds of both being overfat (adjusted odds ratio [aOR] = 0.43, 95% confidence interval [CI] 0.21-0.91, P = 0.027) and overweight (aOR = 0.46, CI 0.26-0.82, P = 0.0083), but the association with prehypertension did not reach statistical significance (aOR = 0.72, CI 0.38-1.37, P = 0.32). Children with a mother who was currently obese were 5 times more likely (aOR = 5.02, CI 2.47-10.20, P < 0.001) to be overfat and over 4 times more likely to be overweight (aOR = 4.33, CI 2.65-7.09, P < 0.001) than children with normal weight mothers. Differences between HIV-exposed and unexposed children on any of the outcomes were minimal and not significant. The main study limitation was that duration of breastfeeding was based on maternal recall.

CONCLUSIONS

To our knowledge, this is the first study examining and quantifying the association between breastfeeding and childhood obesity in an African setting with high HIV prevalence. We observed that breastfeeding was independently associated with reduced childhood obesity for both HIV-exposed and unexposed children, suggesting that promoting optimal nutrition throughout the life course, starting with continued breastfeeding, may be critical to tackling the growing obesity epidemic. In the era of widespread effective antiretroviral treatment for HIV-infected women for life, these data further support the recommendation of breastfeeding for all women.

Anthropometric and clinical correlates of fat mass in healthy term infants at 6 months of age

BACKGROUND

Body composition in infancy plays a central role in the programming of metabolic diseases. Fat mass (FM) is determined by personal and environmental factors. Anthropometric measurements allow for estimations of FM in many age groups; however, correlations of these measurements with FM in early stages of life are scarcely reported. The aim of this study was to evaluate anthropometric and clinical correlates of FM in healthy term infants at 6 months of age.

METHODS

Healthy term newborns (n = 102) from a prospective cohort. Weight, length, skinfolds (biceps, triceps, subscapular and the sum -SFS-) and waist circumference (WC) were measured at 6 months. Body mass index (BMI) and WC/length ratio were computed. Type of feeding during the first 6 months of age was recorded. Air displacement plethysmography was used to asses FM (percentage -%-) and FM index (FMI) was calculated. Correlations and general linear models were performed to evaluate associations.

RESULTS

Significant correlations were observed between all anthropometric measurements and FM (% and index)(p < 0.001). Exclusive/predominant breastfed infants had higher FM and anthropometric measurements at 6 months. Models that showed the strongest associations with FM (% and index) were SFS + WC + sex + type of feeding.

CONCLUSIONS

Anthropometry showed good correlations with FM at 6 months of age. Skinfolds sum and waist circumference were the strongest anthropometric variables associated to FM. Exclusive/predominant breastfeeding was strongly associated with FM.

Risk factors for overweight and overfatness in rural South African children and adolescents

Background

To determine risk factors for overweight/overfatness in children and adolescents from rural KwaZulu-Natal, South Africa.

Methods

Anthropometric data were collected from a cross-sectional sample (n = 1519, ages 7, 11 and 15 years) and linked to demographic information (n = 1310 and n = 1317 in overweight and overfat analyses, respectively). Candidate risk factors for overweight/overfatness were identified and tested for associations with overweight (BMI-for-age >+1SD, WHO reference) and overfatness (>85th centile body fatness, McCarthy reference) as outcomes. Associations were examined using simple tests of proportions (χ²/Mann–Whitney U tests) and multivariable logistic regression.

Results

Sex was a consistent variable across both analyses; girls at significantly increased risk of overweight and overfatness (overweight: n = 180, 73.9 and 26.1% females and males, respectively (P < 0.0001); overfat: n = 187, 72.7 and 27.3% females and males, respectively (P < 0.0001)). In regression analyses, sex and age (defined by school grade) were consistent variables, with boys at lower risk of overweight (adjusted odds ratio (AOR) 0.40 (confidence interval (CI) -0.28–0.57)) and risk of overweight increasing with age (AOR 0.65 (CI- 0.44–0.96), 0.50 (CI-0.33–0.75) and 1.00 for school grades 1, 5 and 9, respectively). Results were similar for overfatness.

Conclusions

This study suggests that pre-adolescent/adolescent females may be the most appropriate targets of future interventions aimed at preventing obesity in rural South Africa.

The challenges of underweight and overweight in South African children: are we winning or losing the battle? A systematic review

Underweight and overweight are adverse effects of malnutrition and both are associated with negative health consequences in children and adolescents. In South Africa, the burden of economic and social disparity coexists with malnutrition in children. The purpose of this study was to review available South Africa studies regarding the comprehensive summary of prevalence of underweight and overweight and evaluates government policies in addressing undernutrition and overnutrition in South African children and adolescents. We searched subject-specific electronic bibliographic databases of observational studies published on malnutrition, undernutrition, overnutrition, underweight and overweight in South African boys and girls from birth to 20 years of age in studies published on or after 1990. A total of sixteen cross-sectional, three longitudinal studies and one report met the criteria for inclusion in this review. Descriptive data synthesis revealed the small number of longitudinal studies highlights the dearth of research in tracking undernutrition and overnutrition in South African children. In this review, 0.7%-66% of underweight was reported among children in rural areas compared to a 3.1%-32.4% of overweight in urban areas. All studies reported a higher rate of underweight in boys than girls who were significantly more likely to have higher body fat. The data indicated that both underweight and overweight were positively related with health-related physical activity and psychological health problems such as low activity, low fitness, low self-image and self-esteem. Numerous recommendations were made in the reviewed studies, however effective strategic programs in eradicating both underweight and overweight are minimal. It is evident from the reviewed studies that the burden of underweight and overweight are still a problem in South African children. The most highly affected by underweight are rural children, while children in urban areas in transition are faced with burden of overweight. There is little evidence to suggest that government strategic programs are effective in addressing underweight and overweight in South African children. Based on these findings, sustainable school-based feeding schemes and physical education programmes are needed for optimal benefits in children and adolescents.

The prevalence of underweight, overweight, obesity and associated risk factors among school-going adolescents in seven African countries

Background

The burden caused by the coexistence of obesity and underweight in Low and Middle Income Countries is a challenge to public health. While prevalence of underweight among youth has been well documented in these countries, overweight, obesity and their associated risk factors are not well understood unlike in high income countries.

Methods

Cross-sectional data from the Global School-based Student Health Survey (GSHS) conducted in seven African countries were used for this study. The survey used a clustered design to obtain a representative sample (n = 23496) from randomly selected schools. 53.6% of the sample was male, and participants ranged in age from 11-17 years old. Body Mass Index (BMI) was calculated using age and sex adjusted self-reported heights and weights. Classification of weight status was based on the 2007 World Health Organization growth charts (BMI-for-age and sex). Multivariable Logistic Regression reporting Odds Ratios was used to assess potential risk factors on BMI, adjusting for age, sex, and country. Statistical analyses were performed with Stata with an alpha of 0.05 and reporting 95% confidence intervals.

Results

Unadjusted rates of being underweight varied from 12.6% (Egypt) to 31.9% (Djibouti), while being overweight ranged from 8.7% (Ghana) to 31.4% (Egypt). Obesity rates ranged from 0.6% (Benin) to 9.3% (Egypt). Females had a higher overweight prevalence for every age group in five of the countries, exceptions being Egypt and Malawi. Overall, being overweight was more prevalent among younger (≤12) adolescents and decreased with age. Males had a higher prevalence of being underweight than females for every country. There was a tendency for the prevalence of being underweight to increase starting in the early teens and decrease between ages 15 and 16. Most of the potential risk factors captured by the GSHS were not significantly associated with weight status.

Conclusions

The prevalence of both overweight and underweight was relatively high, demonstrating the existence of the double burden of malnutrition among adolescents in developing countries. Several factors were not associated with weight status suggesting the need to explore other potential risk factors for overweight and underweight, including genetic factors and socioeconomic status.

Use of mid-upper arm circumference for determining overweight and overfatness in children and adolescents

OBJECTIVE

To assess the use of mid-upper arm circumference (MUAC) for identification of overweight and overfatness in rural South African children and adolescents.

METHODS

Anthropometric data (weight, height, MUAC and % body fat) from a cross-sectional sample of 978 black South African 5-14-year-olds were analysed. Receiver operating characteristic (ROC) curve analysis determined the validity of MUAC as a proxy for determining overweight and overfatness.

FINDINGS

Area under the curve (AUC) results were generally high. Boys and girls aged 10-14 years had ROC-AUC for overfatness classed as 'excellent', 0.97 and 0.98 respectively. Cut-points in the MUAC distribution which optimised the ROC-AUC for identification of overfatness and obesity were determined for boys and girls aged 5-9 and 10-14 years, and had high sensitivity and specificity.

CONCLUSIONS

MUAC may have potential for clinical and surveillance applications as an accurate yet simple and widely available indicator of overweight and overfatness in children and adolescents in resource-poor settings.

Consent and community engagement in diverse research contexts

Consent and community engagement (CE) in health research are two aspects of a single concern-that research is carried out in a respectful manner where social value is maximized. There are important overlaps and interdependencies between consent and CE; for example, CE can provide insights into how best to tailor consent to context and can be an important component of consent processes. Engaging communities can also have intrinsic and instrumental value beyond consent; for example, as a means of showing respect and identifying appropriate ways of working respectfully. In this paper we critically examine how CE and consent processes are characterized, conducted, and evaluated in diverse health research contexts, and propose a preliminary research agenda to support future learning in these critical areas.