Understanding the underlying drivers of obesity in Africa: a scoping review protocol.

INTRODUCTION: The worldwide prevalence of obesity and overweight has doubled since 1980, such that approximately a third of the world's population is reported as obese or overweight. Obesity rates have increased in all ages and both sexes irrespective of geographical area, ethnicity or socioeconomic status. Due to the high prevalence, related health consequences and costs of childhood and adult obesity, there is a need to comprehensively identify and assess the major underlying drivers of obesity and overweight in the African context. METHODS AND ANALYSIS: This scoping review will be carried out as per the methodological outline by Arksey and O'Malley. The search strategy will be developed and search performed in the Scopus and PubMed electronic databases. In the first search, we will identify concepts that are used as an equivalent to obesity and overweight. Subsequently, we will search for studies comprising of search terms on the underlying factors that drive the development of obesity and overweight. Lastly, we will check reference lists for additional publications. Abstracts and full-text studies will independently be screened by two authors. ETHICS AND DISSEMINATION: The proposed study will generate evidence from published data and hence does not require ethics approval. Evidence generated from this review will be disseminated through journal publications and conference presentations.

Regional Overview on the Double Burden of Malnutrition and Examples of Program and Policy Responses: African Region.

Sub-Saharan Africa is experiencing the double burden of malnutrition (DBM) with high levels of undernutrition and a growing burden of overweight/obesity and diet-related noncommunicable diseases (NCDs). Undernourishment in sub-Saharan Africa increased between 2010 and 2016. Although the prevalence of chronic undernutrition is decreasing, the number of stunted children under 5 years of age is increasing due to population growth. Meanwhile, overweight/obesity is increasing in all age groups, with girls and women being more affected than boys and men. It is increasingly recognized that the drivers of the DBM originate outside the health sector and operate across national and regional boundaries. Largely unregulated marketing of cheap processed foods and nonalcoholic beverages as well as lifestyle changes are driving consumption of unhealthy diets in the African region. Progress toward the goal of ending hunger and malnutrition by 2030 requires intensified efforts to reduce undernutrition and focused action on the reduction of obesity and diet-related NCDs. The World Health Organization is developing a strategic plan to guide governments and development partners in tackling all forms of malnutrition through strengthened policies, improved service delivery, and better use of data. It is only through coordinated and complementary efforts that strides can be made to reduce the DBM.

Assessment of the WHO Stunting Framework using Ethiopia as a case study.

Poor linear growth in children <5 years old, or stunting, is a serious public health problem particularly in Sub-Saharan Africa. In 2013, the World Health Organization (WHO) released a conceptual framework on the Context, Causes and Consequences of Childhood Stunting (the 'WHO framework') that identifies specific and general factors associated with stunting. The framework is based upon a global review of data, and we have applied it to a country-level analysis where health and nutrition policies are made and public health and nutrition data are collected. We reviewed the literature related to sub-optimal linear growth, stunting and birth outcomes in Ethiopia as a case study. We found consistent associations between poor linear growth and indicators of birth size, recent illness (e.g. diarrhoea and fever), maternal height and education. Other factors listed as causes in the framework such as inflammation, exposure to mycotoxins and inadequate feeding during and after illness have not been examined in Ethiopia, and the existing literature suggests that these are clear data gaps. Some factors associated with poor linear growth in Ethiopia are missing in the framework, such as household characteristics (e.g. exposure to indoor smoke). Examination of the factors included in the WHO framework in a country setting helps identifying data gaps helping to target further data collection and research efforts. © 2016 John Wiley & Sons Ltd.

Successive 1-Month Weight Increments in Infancy Can Be Used to Screen for Faltering Linear Growth.

BACKGROUND: Linear growth faltering in the first 2 y contributes greatly to a high stunting burden, and prevention is hampered by the limited capacity in primary health care for timely screening and intervention. OBJECTIVE: This study aimed to determine an approach to predicting long-term stunting from consecutive 1-mo weight increments in the first year of life. METHODS: By using the reference sample of the WHO velocity standards, the analysis explored patterns of consecutive monthly weight increments among healthy infants. Four candidate screening thresholds of successive increments that could predict stunting were considered, and one was selected for further testing. The selected threshold was applied in a cohort of Bangladeshi infants to assess its predictive value for stunting at ages 12 and 24 mo. RESULTS: Between birth and age 12 mo, 72.6% of infants in the WHO sample tracked within 1 SD of their weight and length. The selected screening criterion ("event") was 2 consecutive monthly increments below the 15th percentile. Bangladeshi infants were born relatively small and, on average, tracked downward from approximately age 6 to <24 mo (51% stunted). The population-attributable risk of stunting associated with the event was 14% at 12 mo and 9% at 24 mo. Assuming the screening strategy is effective, the estimated preventable proportion in the group who experienced the event would be 34% at 12 mo and 24% at 24 mo. CONCLUSIONS: This analysis offers an approach for frontline workers to identify children at risk of stunting, allowing for timely initiation of preventive measures. It opens avenues for further investigation into evidence-informed application of the WHO growth velocity standards.

Complementary feeding and attained linear growth among 6-23-month-old children.

OBJECTIVE: To examine the association between complementary feeding indicators and attained linear growth at 6-23 months. DESIGN: Secondary analysis of Phase V Demographic and Health Surveys data (2003-2008). Country-specific ANOVA models were used to estimate effects of three complementary feeding indicators (minimum meal frequency, minimum dietary diversity and minimum adequate diet) on length-for-age, adjusted for covariates and interactions of interest. SETTING: Twenty-one countries (four Asian, twelve African, four from the Americas and one European). SUBJECTS: Sample sizes ranging from 608 to 13 676. RESULTS: Less than half the countries met minimum meal frequency and minimum dietary diversity, and only Peru had a majority of the sample receiving a minimum adequate diet. Minimum dietary diversity was the indicator most consistently associated with attained length, having significant positive effect estimates (ranging from 0·16 to 1·40 for length-for-age Z-score) in twelve out of twenty-one countries. Length-for-age declined with age in all countries, and the greatest declines in its Z-score were seen in countries (Niger, -1·9; Mali, -1·6; Democratic Republic of Congo, -1·4; Ethiopia, -1·3) where dietary diversity was persistently low or increased very little with age. CONCLUSIONS: There is growing recognition that poor complementary feeding contributes to the characteristic negative growth trends observed in developing countries and therefore needs focused attention and its own tailored interventions. Dietary diversity has the potential to improve linear growth. Using four food groups to define minimum dietary diversity appears to capture enough information in a simplified, standard format for multi-country comparisons of the quality of complementary diets.

The World Health Organization's global target for reducing childhood stunting by 2025: rationale and proposed actions.

In 2012, the World Health Organization adopted a resolution on maternal, infant and young child nutrition that included a global target to reduce by 40% the number of stunted under-five children by 2025. The target was based on analyses of time series data from 148 countries and national success stories in tackling undernutrition. The global target translates to a 3.9% reduction per year and implies decreasing the number of stunted children from 171 million in 2010 to about 100 million in 2025. However, at current rates of progress, there will be 127 million stunted children by 2025, that is, 27 million more than the target or a reduction of only 26%. The translation of the global target into national targets needs to consider nutrition profiles, risk factor trends, demographic changes, experience with developing and implementing nutrition policies, and health system development. This paper presents a methodology to set individual country targets, without precluding the use of others. Any method applied will be influenced by country-specific population growth rates. A key question is what countries should do to meet the target. Nutrition interventions alone are almost certainly insufficient, hence the importance of ongoing efforts to foster nutrition-sensitive development and encourage development of evidence-based, multisectoral plans to address stunting at national scale, combining direct nutrition interventions with strategies concerning health, family planning, water and sanitation, and other factors that affect the risk of stunting. In addition, an accountability framework needs to be developed and surveillance systems strengthened to monitor the achievement of commitments and targets.

Contextualising complementary feeding in a broader framework for stunting prevention.

An estimated 165 million children are stunted due to the combined effects of poor nutrition, repeated infection and inadequate psychosocial stimulation. The complementary feeding period, generally corresponding to age 6-24 months, represents an important period of sensitivity to stunting with lifelong, possibly irrevocable consequences. Interventions to improve complementary feeding practices or the nutritional quality of complementary foods must take into consideration the contextual as well as proximal determinants of stunting. This review presents a conceptual framework that highlights the role of complementary feeding within the layers of contextual and causal factors that lead to stunted growth and development and the resulting short- and long-term consequences. Contextual factors are organized into the following groups: political economy; health and health care systems; education; society and culture; agriculture and food systems; and water, sanitation and environment. We argue that these community and societal conditions underlie infant and young child feeding practices, which are a central pillar to healthy growth and development, and can serve to either impede or enable progress. Effectiveness studies with a strong process evaluation component are needed to identify transdisciplinary solutions. Programme and policy interventions aimed at preventing stunting should be informed by careful assessment of these factors at all levels.

Multi-sectoral interventions for healthy growth.

The risk of stunted growth and development is affected by the context in which a child is born and grows. This includes such interdependent influences as the political economy, health and health care, education, society and culture, agriculture and food systems, water and sanitation, and the environment. Here, we briefly review how factors linked with the key sectors can contribute to healthy growth and reduced childhood stunting. Emphasis is placed on the role of agriculture/food security, especially family farming; education, particularly of girls and women; water, sanitation, and hygiene and their integration in stunting reduction strategies; social protection including cash transfers, bearing in mind that success in this regard is linked to reducing the gap between rich and poor; economic investment in stunting reduction including the work with the for-profit commercial sector balancing risks linked to marketing foods that can displace affordable and more sustainable alternatives; health with emphasis on implementing comprehensive and effective health care interventions and building the capacity of health care providers. We complete the review with examples of national and subnational multi-sectoral interventions that illustrate how critical it is for sectors to work together to reduce stunting.

Parental height and child growth from birth to 2 years in the WHO Multicentre Growth Reference Study.

Linear growth from birth to 2 years of children enrolled in the World Health Organization Multicentre Growth Reference Study was similar despite substantial parental height differences among the six study sites. Within-site variability in child length attributable to parental height was estimated by repeated measures analysis of variance using generalized linear models. This approach was also used to examine relationships among selected traits (e.g. breastfeeding duration and child morbidity) and linear growth between 6 and 24 months of age. Differences in intergenerational adult heights were evaluated within sites by comparing mid-parental heights (average of the mother's and father's heights) to the children's predicted adult height. Mid-parental height consistently accounted for greater proportions of observed variability in attained child length than did either paternal or maternal height alone. The proportion of variability explained by mid-parental height ranged from 11% in Ghana to 21% in India. The average proportion of between-child variability accounted for by mid-parental height was 16% and the analogous within-child estimate was 6%. In the Norwegian and US samples, no significant differences were observed between mid-parental and children's predicted adult heights. For the other sites, predicted adult heights exceeded mid-parental heights by 6.2-7.8 cm. To the extent that adult height is predicted by height at age 2 years, these results support the expectation that significant community-wide advances in stature are attainable within one generation when care and nutrition approximate international recommendations, notwithstanding adverse conditions likely experienced by the previous generation.

Comparison of the World Health Organization growth velocity standards with existing US reference data.

OBJECTIVE: The goal of this study was to compare World Health Organization (WHO) growth velocity standards with reference data based on US children. METHODS: Comparisons were made between reference values for weight and length gains based on serial data from US children and the WHO child growth standards. We compared weight velocities for boys and girls for selected percentiles (5th, 25th, 50th, 75th, and 95th) for 1-month intervals from birth to 6 months, 2-month intervals up to 12 months, and 3-month intervals up to 24 months. For length, we compared 2-month intervals from birth to 6 months and 3-month intervals up to 24 months. RESULTS: WHO and US monthly weight increments were similar at the 5th percentile up to 3 months of age; values for other US percentiles were below the WHO percentiles ∼150 g on average. From 3 months onward, the US values converged to a narrow range of <100 g between estimated percentiles. Two- and 3-month weight gains showed similar variations. Differences between the WHO and US values were more pronounced at the lower end of the distribution. For length, medians were in closer agreement, but as occurred with weight, values at the outer US percentiles converged to a narrower range with increasing age compared with those of the WHO standards. CONCLUSIONS: There are important differences between the WHO standards and the reference values for growth velocity based on US data. The WHO values are a better tool for assessing growth velocity and making clinical decisions.

Post-partum weight change patterns in the WHO Multicentre Growth Reference Study.

The interplay of factors that affect post-partum loss or retention of weight gained during pregnancy is not fully understood. The objective of this paper is to describe patterns of weight change in the six sites of the World Health Organization (WHO) Multicentre Growth Reference Study (MGRS) and explore variables that explain variation in weight change within and between sites. Mothers of 1743 breastfed children enrolled in the MGRS had weights measured at days 7, 14, 28 and 42 post-partum, monthly from 2 to 12 months and bimonthly thereafter until 24 months post-partum. Height, maternal age, parity and employment status were recorded and breastfeeding was monitored throughout the follow-up. Weight change patterns varied significantly among sites. Ghanaian and Omani mothers lost little or gained weight post-partum. In Brazil, India, Norway and USA, mothers on average lost weight during the first year followed by stabilization in the second year. Lactation intensity and duration explained little of the variation in weight change patterns. In most sites, obese mothers tended to lose less weight than normal-weight mothers. In Brazil and Oman, primiparous mothers lost about 1 kg more than multiparous mothers in the first 6 months. In India and Ghana, multiparous mothers lost about 0.6 kg more than primiparas in the second 6 months. Culturally defined mother-care practices probably play a role in weight change patterns among lactating women. This hypothesis should stimulate investigation into gestational weight gain and post-partum losses in different ethnocultural contexts.

Development of a WHO growth reference for school-aged children and adolescents.

OBJECTIVE: To construct growth curves for school-aged children and adolescents that accord with the WHO Child Growth Standards for preschool children and the body mass index (BMI) cut-offs for adults. METHODS: Data from the 1977 National Center for Health Statistics (NCHS)/WHO growth reference (1-24 years) were merged with data from the under-fives growth standards' cross-sectional sample (18-71 months) to smooth the transition between the two samples. State-of-the-art statistical methods used to construct the WHO Child Growth Standards (0-5 years), i.e. the Box-Cox power exponential (BCPE) method with appropriate diagnostic tools for the selection of best models, were applied to this combined sample. FINDINGS: The merged data sets resulted in a smooth transition at 5 years for height-for-age, weight-for-age and BMI-for-age. For BMI-for-age across all centiles the magnitude of the difference between the two curves at age 5 years is mostly 0.0 kg/m(2) to 0.1 kg/m(2). At 19 years, the new BMI values at +1 standard deviation (SD) are 25.4 kg/m(2) for boys and 25.0 kg/m(2) for girls. These values are equivalent to the overweight cut-off for adults (> or = 25.0 kg/m(2)). Similarly, the +2 SD value (29.7 kg/m(2) for both sexes) compares closely with the cut-off for obesity (> or = 30.0 kg/m(2)). CONCLUSION: The new curves are closely aligned with the WHO Child Growth Standards at 5 years, and the recommended adult cut-offs for overweight and obesity at 19 years. They fill the gap in growth curves and provide an appropriate reference for the 5 to 19 years age group.

Comparison of the WHO child growth standards and the CDC 2000 growth charts.

The evaluation of child growth trajectories and the interventions designed to improve child health are highly dependent on the growth charts used. The U.S. CDC and the WHO, in May 2000 and April 2006, respectively, released new growth charts to replace the 1977 NCHS reference. The WHO charts are based for the first time on a prescriptive, prospective, international sample of infants selected to represent optimum growth. This article compares the WHO and CDC curves and evaluates the growth performance of healthy breast-fed infants according to both. As expected, there are important differences between the WHO and CDC charts that vary by age group, growth indicator, and specific Z-score curve. Differences are particularly important during infancy, which is likely due to differences in study design and characteristics of the sample, such as type of feeding. Overall, the CDC charts reflect a heavier, and somewhat shorter, sample than the WHO sample. This results in lower rates of undernutrition (except during the first 6 mo of life) and higher rates of overweight and obesity when based on the WHO standards. Healthy breast-fed infants track along the WHO standard's weight-for-age mean Z-score while appearing to falter on the CDC chart from 2 mo onwards. Shorter measurement intervals in the WHO standards result in a better tool for monitoring the rapid and changing rate of growth in early infancy. Their adoption would have important implications for the assessment of lactation performance and the adequacy of infant feeding and would bring coherence between the tools used to assess growth and U.S. national guidelines that recommend breast-feeding as the optimal source of nutrition during infancy.

Field-testing the WHO child growth standards in four countries.

In April 2006 the WHO released a set of growth standards for children from birth to the age of 5 y. Prior to their release, the standards were field-tested in 4 countries. The main objective was to compare children's length/height-for-age and weight-for-length/height based on the new standards with clinician assessments of the same children. The study sampled children <5-y-old attending well-child clinics in 2 affluent populations (Argentina and Italy) and 2 less-affluent ones (Maldives and Pakistan). Length/height and weight were measured by doctors and epidemiologists who also recorded a clinical assessment of each child's length/height in relation to age and weight relative to length/height. Anthropometric indicators of nutritional status were generated based on the WHO standards. As expected, Pakistan and the Maldives had higher rates of stunting, wasting, and underweight than Italy and Argentina, and the reverse was true for overweight and obesity. Where stunting was prevalent, the children classified as short were a mean <-2 SD for height-for-age. In all sites, the children classified as thin were indeed wasted (<-2 SD for weight-for-height) and a positive association in trend was evident between weight-for-height and the line-up of groups from thin to obese. The overall concordance between clinical assessments and the WHO standards-based indicators attested to the clinical soundness of the standards.

Comparison of the World Health Organization (WHO) Child Growth Standards and the National Center for Health Statistics/WHO international growth reference: implications for child health programmes.

OBJECTIVES: To compare growth patterns and estimates of malnutrition based on the World Health Organization (WHO) Child Growth Standards ('the WHO standards') and the National Center for Health Statistics (NCHS)/WHO international growth reference ('the NCHS reference'), and discuss implications for child health programmes. DESIGN: Secondary analysis of longitudinal data to compare growth patterns (birth to 12 months) and data from two cross-sectional surveys to compare estimates of malnutrition among under-fives. SETTINGS: Bangladesh, Dominican Republic and a pooled sample of infants from North America and Northern Europe. SUBJECTS: Respectively 4787, 10 381 and 226 infants and children. RESULTS: Healthy breast-fed infants tracked along the WHO standard's weight-for-age mean Z-score while appearing to falter on the NCHS reference from 2 months onwards. Underweight rates increased during the first six months and thereafter decreased when based on the WHO standards. For all age groups stunting rates were higher according to the WHO standards. Wasting and severe wasting were substantially higher during the first half of infancy. Thereafter, the prevalence of severe wasting continued to be 1.5 to 2.5 times that of the NCHS reference. The increase in overweight rates based on the WHO standards varied by age group, with an overall relative increase of 34%. CONCLUSIONS: The WHO standards provide a better tool to monitor the rapid and changing rate of growth in early infancy. Their adoption will have important implications for child health with respect to the assessment of lactation performance and the adequacy of infant feeding. Population estimates of malnutrition will vary by age, growth indicator and the nutritional status of index populations.

The WHO Multicentre Growth Reference Study: planning, study design, and methodology.

The World Health Organization (WHO) Multicentre Growth Reference Study (MGRS) is a community-based, multicountry project to develop new growth references for infants and young children. The design combines a longitudinal study from birth to 24 months with a cross-sectional study of children aged 18 to 71 months. The pooled sample from the six participating countries (Brazil, Ghana, India, Norway, Oman, and the United States) consists of about 8,500 children. The study subpopulations had socioeconomic conditions favorable to growth, and low mobility, with at least 20% of mothers following feeding recommendations and having access to breastfeeding support. The individual inclusion criteria were absence of health or environmental constraints on growth, adherence to MGRS feeding recommendations, absence of maternal smoking, single term birth, and absence of significant morbidity. In the longitudinal study, mothers and newborns were screened and enrolled at birth and visited at home 21 times: at weeks 1, 2, 4, and 6; monthly from 2 to 12 months; and every 2 months in their second year. In addition to the data collected on anthropometry and motor development, information was gathered on socioeconomic, demographic, and environmental characteristics, perinatal factors, morbidity, and feeding practices. The prescriptive approach taken is expected to provide a single international reference that represents the best description of physiological growth for all children under five years of age and to establish the breastfed infant as the normative model for growth and development.