Nutritional and Health-Related Environmental Studies (NAHRES)

Doctoral CRP on longitudinal measures of body composition of healthy infants and young children up to 2 years of age using stable isotope techniques.

Brief summary

It is now recognised that adequate growth during the period from conception to two years of age is crucial to decreasing the risk of ill-health in later life; the concept of developmental origins of disease. Despite this recognition there is a paucity of data of what constitutes normal growth beyond simple anthropometric measurements of weight and height. These measures do not capture the “quality” of growth in terms of body composition, the relative amounts of fat and lean tissue. Two individuals can have the same weight and height but differ markedly in the proportions of fat and lean and hence risk of non-communicable diseases in later life. Unfortunately information on changes in body composition during the first two years of life is lacking. Although measurement of body composition in the infant can be challenging, it can be accomplished by using isotopic procedures. The IAEA has been a leader in this area, developing and promoting the use of standardised protocols for body composition assessment using such techniques. The overall aim of this CRP is to use this knowledge to assess longitudinal changes in body composition that occur in healthy infants and children up to age two years. This will contribute new information on growth of healthy infants and young children. This CRP has a strong focus on training and education and will contribute to capacity building in nuclear techniques in nutrition by training of PhD students in developing countries.

Background

The developing world is confronted by the double burden of malnutrition, i.e., the coexistence of under- and over-nutrition (1). The most vulnerable population groups include mothers and their infants and young children. Despite the widespread recognition that poor nutrition is a major risk factor for ill health in adults (2), this has recently been identified as one of the most neglected aspects of maternal, newborn, and child health (3). Early in life, the structure and function of the body underpins both short- and longer-term health outcomes, yet, surprisingly, there are little data on the body composition of healthy infants and young children. The crucial time during which the biology of physical growth and development can be most influenced by nutrition (either positively or negatively), encompasses pregnancy and the first two years of life (4, 5). This period has recently been referred to as the “1000 day window of opportunity” (http://www.thousanddays.org/) to stress the importance of investments in maternal and child nutrition and to emphasise that nutrition interventions during this window provide the best opportunity for prevention of longer-term consequences of early under-nutrition. This CRP addresses the question ‘What are the changes in body composition that occur in healthy children aged 0 to 24 months?’

Body composition to monitor the quality of growth of infants and young children

There is now strong evidence that growth from conception to 2 years of age represents a critical “window of opportunity” in terms of later risk of ill-health and is central to the concept of the developmental origins of adult disease (6). However, the assessment of growth during this crucial period of early vulnerability is largely based on anthropometric measurements such as body weight, with insufficient attention to the relative partitioning of nutrients to fat-free mass (FFM) or fat mass (FM). At attended delivery, birth weight, length and head circumference might be measured as major indicators of pregnancy outcome and growth during infancy and childhood, comparing measurements against the new WHO Child Growth Standards (7, 8). However, infants of similar weight, height or even weight for height, can vary substantially in body composition. For example, Indian babies have been characterised as having the thin-fat phenotype because although small and thin at birth they have proportionally more body fat and centrally deposited fat than European newborns (9). This difference in body composition phenotype appears to be related to birth size and marks a fundamental metabolic difference and greater risk of later non-communicable diseases during adult life (10). These observations emphasise the importance of more detailed characterisation of body structure and composition to identify high risk of poor health at an early age (11).

Body weight is a simple and informative measurement with which to mark adequate nutrition and short term risk, for example as used as the basis for the first Millennium Development Goal of halving the proportion of underweight children by 2015 (http://www.un.org/millenniumgoals/). However, weight alone does not adequately reflect risks in the longer term of poor child growth and its consequences on health and development. For many countries in transition, improvements in child weight have taken place without improvements in linear growth with the result that if height is measured, normal weight children are increasingly identified as short and relatively fat (12, 13). This raises concern about the “quality of growth” and the implications for poor metabolic regulation and risk of later ill-health. These observations highlight the importance of reliable measurements of length/height at the same time as body weight, to better define healthy growth (14).

However, it is clear that even though accurate and reliable measurements of height and weight provide useful information, there is an overriding need to better capture the dynamic nature of growth during early life by assessment of body composition i.e., the partitioning of FM and FFM. The assessment of body composition is important in the short term in relation to the quality of diets used in the prevention and treatment of moderate and severely malnourished children, and to optimise intervention strategies (15). The reliable measurement of body composition during early life represents a technically challenging area to be addressed within this CRP by stable isotope dilution technique for total body water (TBW) assessment. Other methodologies, such as air-displacement plethysmography and/or dual-energy X-ray absorptiometry (DXA) may be used when available (16). Standardisation of TBW and DXA protocols has been initiated by the IAEA for adults and older children (17-20) and extended to applications in newborns and children up to 2 years of age in a forthcoming document (21).

In summary, the use of stable isotope techniques to assess body composition in infants and young children represents a unique opportunity to collect much needed information on healthy growth and to contribute to capacity building in this priority area.

Analytical techniques to be used

Stable isotope techniques will be used to measure total body water for the assessment of body composition in infants and young children following procedures described in references 17 and 18. Analysis of stable isotope enrichment in saliva samples will be made by Fourier Transform Infrared spectrometry (FTIR, 17), or where available, Isotope Ratio Mass Spectrometry (IRMS, 18).

Overall objective

The overall objective is to assess longitudinal changes in body composition (fat mass and fat free mass) of healthy infants and young children during the first 2 years of life.

Specific research objective (purpose)

The proposed Doctoral CRP intends to:

  • To assess longitudinally body composition of healthy young children by stable isotope techniques at 3, 6, 9, 12, 18 and 24 months of age;
  • To contribute to capacity building in nutrition by supporting PhD students.
Expected research outputs
  • New data on the longitudinal changes in body composition in children during the first two years of life.
  • PhD theses.
  • Publications in the form of scientific reports and peer-reviewed papers.
Expected research outcomes
  • To contribute to improved understanding of growth during the first 2 years of life;
  • To contribute to capacity building in nutrition by training of PhD students.
Proposal submission forms

Research institutions in Member States interested in participating in this CRP are invited to submit proposals directly to the Research Contracts Administration Section (NACA) of the International Atomic Energy Agency: Official.Mail@iaea.org or to Ms Najat Mokhtar: N.Mokhtar@iaea.org

The forms can be downloaded from http://www-crp.iaea.org/html/forms.html. For more information about research contracts and research agreements, please visit our web-site: http://www-crp.iaea.org/html/faqs.html.


Deadline for submission of proposal

Proposals must be received no later than 15 March 2013. Transmission via Email is acceptable if all required signatures are scanned.

For additional information, please contact:
Najat Mokhtar
Section Head
Nutritional and Health-related Environmental Studies Section
Division of Human Health
International Atomic Energy Agency (IAEA)
A-1400 Vienna, Austria
Phone: + 43 1 2600 21657 or 21674
Fax: + 43 1 2600-7
N.Mokhtar@iaea.org

References
  1. CABALLERO, B., A nutrition paradox – underweight and obesity in developing countries, N. Engl. J. Med. 352 (2005) 1514–6.
  2. LOPEZ, A.D., MATHERS, C.D., EZZATI, M., JAMISON, D.T., MURRAY, C.J.L., Global and regional burden of disease and risk factors, 2001: systematic analysis of population health data, Lancet 367 (2006) 1747-57.
  3. HORTON, R., Maternal and child undernutrition: an urgent opportunity, Lancet 371 (2008) 179.
  4. WORLD BANK, Repositioning nutrition as central to development. The International Bank for Reconstruction and Development/The World Bank, Washington DC (2006).
  5. The Lancet Series on Maternal and Child Undernutrition, Executive Summary, The Lancet (2008).
  6. BARKER, D.J., The developmental origins of adult disease, J. Am. Coll. Nutr. 3 Suppl. 6 (2004) 588S–95S.
  7. WORLD HEALTH ORGANIZATION. Child growth standards: Methods and development: Length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age, WHO, Geneva, (2007). http://www.who.int/childgrowth/publications/technical_report_pub/en/index.html
  8. VICTORA, C.G., DE ONIS, M., HALLAL, P.C., BLOSSNER, M., SHRIMPTON, R., Worldwide timing of growth faltering: revisiting implications for interventions, Pediatrics. 125 3 (2010) e473-80.
  9. YAYNIK, C.S., FALL, C.H., COYAJI, K.J., HIRVE, S.S., RAO, S., BARKER, D.J., JOGLEKAR, C,, KELLINGRAY, S., Neonatal anthropometry: the thin-fat Indian baby. The Pune maternal nutrition study, Int. J. Obes. Relat. Metab. Disord. 27 2 (2003) 173-80.
  10. KENSARA, O.A., WOOTON, S.A., PHILLIPS, D.I., PATEL, M., HOFFMAN, D.J., JACKSON, A.A., ELIA, M., Hertfordshire Study Group. Substrate-energy metabolism and metabolic risk factors for cardiovascular disease in relation to fetal growth and adult body composition, Am. J. Physiol. Endocrinol. Metab. 291 2 (2006) E365-71.
  11. CORVALAN C, KAIN J, WEISSTAUB G, UAUY R. Impact of growth patterns and early diet on obesity and cardiovascular risk factors in young children from developing countries. Proc Nutr Soc. 2009; 68(3), 327-37.
  12. KAIN J, CORVALAN C, LERA L, GALVAN M, UAUY R. Accelerated growth in early life and obesity in preschool Chilean children. Obesity (Silver Spring). 2009; 17(8), 1603-1608.
  13. IANNOTTI LL, ZAVALETA N, LEON Z, CAUFIELD LE. Growth and body composition of Peruvian infants in a periurban setting. Food Nutr Bull. 2009; 30(3), 245-53.
  14. UAUY, R., ROJAS, J., CORVALAN, C., LERA, L.,KAIN, J., Prevention and control of obesity in preschool children: importance of normative standards. J. Pediatr. Gastroentrol. Nutr. 43 suppl. 3 (2006) S26-37.
  15. LARTEY A. Maternal and child nutrition in Sub-Saharan Africa: challenges and interventions. Proc Nutr Soc. 2008; 67, 105–108.
  16. ELLIS KJ. Evaluation of body composition in neonates and infants. Semin Fetal Neonatal Med. 2007; 12, 87-91.
  17. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA), Human Health Series No 3. Assessment of body composition and total energy expenditure in humans Using Stable Isotope Techniques.
  18. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA), Human Health Series No 12. Introduction to body composition assessment using the deuterium dilution technique with analysis of saliva samples by Fourier Transform Infrared Spectrometry (FTIR).
  19. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA), Human Health Series No 13. Introduction to body composition assessment using the deuterium dilution technique with analysis of urine samples by Isotope Ratio Mass Spectrometry.
  20. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA), Human Health Series No 15. Dual energy X ray absorptiometry for bone mineral density and body composition assessment.
  21. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA), Human Health Series. Body Composition Assessment from Birth to 2 Years of Age (in press).