Ten per cent of the world’s school-aged children are estimated to be carrying excess body fat (Fig. 1), with an increased risk for developing chronic disease. Of these overweight children, a quarter are obese, with a significant likelihood of some having multiple risk factors for type 2 diabetes, heart disease and a variety of other co-morbidities before or during early adulthood. The prevalence of overweight is dramatically higher in economically developed regions, but is rising significantly in most parts of the world. In many countries the problem of childhood obesity is worsening at a dramatic rate. Surveys during the 1990s show that in Brazil and the USA, an additional 0.5% of the entire child population became overweight each year. In Canada, Australia and parts of Europe the rates were higher, with an additional 1% of all children becoming overweight each year. The burden upon the health services cannot yet be estimated. Although childhood obesity brings a number of additional problems in its train – hyperinsulinaemia, poor glucose tolerance and a raised risk of type 2 diabetes, hypertension, sleep apnoea, social exclusion and depression – the greatest health problems will be seen in the next generation of adults as the present childhood obesity epidemic passes through to adulthood. Greatly increased rates of heart disease, diabetes, certain cancers, gall bladder disease, osteoarthritis, endocrine disorders and other obesityrelated conditions will be found in young adult populations, and their need for medical treatment may last for their remaining life-times. The costs to the health services, the losses to society and the burdens carried by the individuals involved will be great. The present report has been written to focus attention on the issue and to urge policy-makers to consider taking action before it is too late. Specifically, the report:

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1467-789X.2004.00133.x

Obesity in children and young people: a crisis in public health.

Although the health benefits of breastfeeding are acknowledged widely, opinions and recommendations are divided on the optimal duration of exclusive breastfeeding. We systematically reviewed available evidence concerning the effects on child health, growth, and development and on maternal health of exclusive breastfeeding for 6 months vs. exclusive breastfeeding for 3-4 months followed by mixed breastfeeding (introduction of complementary liquid or solid foods with continued breastfeeding) to 6 months. Two independent literature searches were conducted, together comprising the following databases: MEDLINE (as of 1966), Index Medicus (prior to 1966), CINAHL, HealthSTAR, BIOSIS, CAB Abstracts, EMBASE-Medicine, EMBASE-Psychology, Econlit, Index Medicus for the WHO Eastern Mediterranean Region, African Index Medicus, Lilacs (Latin American and Carribean literature), EBM Reviews-Best Evidence, the Cochrane Database of Systematic Reviews, and the Cochrane Controlled Trials Register. No language restrictions were imposed. The two searches yielded a total of 2,668 unique citations. Contacts with experts in the field yielded additional published and unpublished studies. Studies were stratified according to study design (controlled trials vs. observational studies) and provenance (developing vs. developed countries). The main outcome measures were weight and length gain, weight-for-age and length-for-age z-scores, head circumference, iron status, gastrointestinal and respiratory infectious morbidity, atopic eczema, asthma, neuromotor development, duration of lactational amenorrhea, and maternal postpartum weight loss. Twenty independent studies meeting the selection criteria were identified by the literature search: 9 from developing countries (2 of which were controlled trials in Honduras) and 11 from developed countries (all observational studies). Neither the trials nor the observational studies suggest that infants who continue to be exclusively breastfed for 6 months show deficits in weight or length gain, although larger sample sizes would be required to rule out modest increases in the risk of undernutrition. The data are conflicting with respect to iron status but suggest that, at least in developing-country settings, where iron stores of newborn infants may be suboptimal, exclusive breastfeeding without iron supplementation through 6 months of age may compromise hematologic status. Based primarily on an observational analysis of a large randomized trial in Belarus, infants who continue exclusive breastfeeding for 6 months or more appear to have a significantly reduced risk of one or more episodes of gastrointestinal tract infection. No significant reduction in risk of atopic eczema, asthma, or other atopic outcomes has been demonstrated in studies from Finland, Australia, and Belarus. Data from the two Honduran trials suggest that exclusive breastfeeding through 6 months of age is associated with delayed resumption of menses and more rapid postpartum weight loss in the mother. Infants who are breastfed exclusively for 6 months experience less morbidity from gastrointestinal tract infection than infants who were mixed breastfed as of 3 or 4 months of age. No deficits have been demonstrated in growth among infants from either developing or developed countries who are exclusively breastfed for 6 months or longer. Moreover, the mothers of such infants have more prolonged lactational amenorrhea and faster postpartum weight loss. Based on the results of this review, the World Health Assembly adopted a resolution to recommend exclusive breastfeeding for 6 months to its member countries. Large randomized trials are recommended in both developed and developing countries to ensure that exclusive breastfeeding for 6 months does not increase the risk of undernutrition (growth faltering), to confirm the health benefits reported thus far, and to investigate other potential effects on health and development, especially over the long term.

The optimal duration of exclusive breastfeeding: a systematic review.

Thorough training, continuous standardization, and close monitoring of the adherence to measurement procedures during data collection are essential for minimizing random error and bias in multicenter studies. Rigorous anthropometry and data collection protocols were used in the WHO Multicentre Growth Reference Study to ensure high data quality. After the initial training and standardization, study teams participated in standardization sessions every two months for a continuous assessment of the precision and accuracy of their measurements. Once a year the teams were restandardized against the WHO lead anthropometrist, who observed their measurement techniques and retrained any deviating observers. Robust and precise equipment was selected and adapted for field use. The anthropometrists worked in pairs, taking measurements independently, and repeating measurements that exceeded preset maximum allowable differences. Ongoing central and local monitoring identified anthropometrists deviating from standard procedures, and immediate corrective action was taken. The procedures described in this paper are a model for research settings.

Measurement and standardization protocols for anthropometry used in the construction of a new international growth reference.

Linear growth failure is the most common form of undernutrition globally. With an estimated 165 million children below 5 years of age affected, stunting has been identified as a major public health priority, and there are ambitious targets to reduce the prevalence of stunting by 40% between 2010 and 2025. We view this condition as a ‘stunting syndrome’ in which multiple pathological changes marked by linear growth retardation in early life are associated with increased morbidity and mortality, reduced physical, neurodevelopmental and economic capacity and an elevated risk of metabolic disease into adulthood. Stunting is a cyclical process because women who were themselves stunted in childhood tend to have stunted offspring, creating an intergenerational cycle of poverty and reduced human capital that is difficult to break. In this review, the mechanisms underlying linear growth failure at different ages are described, the short-, medium- and long-term consequences of stunting are discussed, and th...

https://www.tandfonline.com/doi/pdf/10.1179/2046905514Y.0000000158

The stunting syndrome in developing countries

Prevalence and trends of overweight among preschool children in developing countries

An international effort is underway to develop a new international growth reference for assessing the growth of young children, especially breastfed infants who appear to falter relative to the currently recommended National Center for Health Statistics/World Health Organization reference. While limited data from high socioeconomic status children from different parts of the world suggest that their growth patterns are similar, there is no comprehensive study of breastfed infants. The WHO Multinational Study of Breastfeeding and Lactational Amenorrhea provides bi‐weekly weights and 2‐4 weekly length measurements on breastfed babies from selected sites in Australia, Chile, China, Guatemala, India, Nigeria and Sweden. Multi‐level modelling was used to analyse between‐site differences in the growth of approximately 120 infants per site, after adjustment for maternal stature and infant feeding pattern. All mothers were literate and mean educational levels were well above national averages, but the study was not restricted to infants of high socioeconomic status. Maternal education was significantly associated with infant weight only in India. The growth curves of infants from most sites were strikingly similar, but relative to the Australians (the reference category), the Chinese babies were about 3% shorter at 12 mo of age and the Indians up to 15% lighter. The present results suggest that breastfed babies from reasonably well‐off families in different continents show very similar growth patterns. However, it is important that the growth of children from South and East Asian populations be rigorously assessed in the process of developing the new international growth reference. This paper discusses the relative importance of environmental versus genetic influences in the growth of young children and illustrates the complexities involved in the analysis of growth data.

Ea A. Frongillo

Papers

Growth patterns of breastfed infants in seven countries