Growth and Development

1. Growth and Development Intrauterine growth and nutrient accretion Body Composition Growth Assessment Growth Charts Patterns Alterations in Growth Development Metabolic Physiologic neurologic

2. Growth

3. Growth A normal, healthy child grows at a genetically predetermined rate that can be compromised by imbalanced nutrient intake

4. Growth Growth is a dynamic process defined as an increase in the physical size of the body as a whole or any of its parts associated with increase in cell number and/or cell size Reflects changes in absolute size, mass, body composition

5. Undernutrition ⇩⇩ weight⇒⇒⇩length or height Underweight ⇒⇒ proportionate

6. Fetal Growth from 25-40 weeks GA • Weight increases 4-fold • Length and OFC increase 2-fold

7. Body Composition • Fat accounts for 0.5% of body weight at the fifth month of fetal growth and 16% at term. • 3rd trimester: increase from 1-3% of body weight to 10-16% of body weight at term

8. Minerals • Two-thirds of mineral content of full-term newborn is accummulated in the last trimester of pregnancy.

10. Energy Reserves

11. Determinants of fetal growth • Genetics • Maternal/paternal genes, race, sex estimated to account for 20% of variance in birth weight • Environmental factors

12. Maternal health Nutrition Glucose, fatty acids, amino acids for tissue deposition and fuel for oxidative purposes Ability of maternal-placental system to transfer nutrients to fetus Endocrine environment E.g. LGA infant: glucose-insulin-growth factors Environmental factors

13. Individual Growth Patterns • Weight and length at term appear to be primarily determined by nongenetic maternal factors • Birth weigh and birth length weakly correlate with subsequent weight and length values

14. Individual Growth Patterns, cont. • African American males and females are smaller than whites at birth, but they grow more rapidly during the first 2 years • Patterns of growth in breastfed infants are different from formula fed infants

15. GROWTH IN FIRST 12 MONTHS • From birth to 1 year of age, normal human infants triple their weight and increase their length by 50%. • Growth in the first 4 months of life is the fastest of the whole lifespan - birthweight usually doubles by 4 months • 4-8 months is a time of transition to slower growth • By 8 months growth patterns more like those of 2 year old than those of newborn.

16. Body Composition • BMI and percentage of body weight made up of fat increase rapidly during the first months of life • After birth, fat accumulates rapidly until approximately 9 months of age

17. Weight Gain in Grams per Day in One Month Increments - Girls Guo et al., J Peds. 1991

18. Weight Gain in Grams per Day in One Month Increments - Boys Guo et al., J Peds. 1991

19. Weight gain of Breast fed vs bottle fedinfants: 8-112 days of age (g/d) Nelson et al Early Human Development 19:223 1989

20. Rates of gain for breastfed and formula fed infants during early months of life generally have been found to be similar although some reports have demonstrated greater gains by breastfed infants and others have shown greater gains by formula fed infants

21. Assessment • Screening identifies nutritional risk and/or need for further assessment. • Underweight • Overweight • Failure to grow • “over fat”

22. Reference vs Standard • Reference: a set of data used for normalizing measurements so that they can be manipulated statistically, grouped and compared with other sets of measurements. In principle, implies no value judgement and tells us nothing about optimal or satisfactory growth • Standard: Implies a value judgement. In theory, standards are selected based on representing “optimal”, “normal” or “goal”

23. Fetal/Neonatal Growth Charts • Intrauterine charts • Classification of newborn • AGA • LGA • SGA • Postnatal Charts

24. Intrauterine/Fetal Growth Standards • Lubchenco • Gairdner • Babson Benda • Fenton • Olsen

25. Fetal Growth Data

26. Fenton Chart Data Sets: Kramer et al: 676,605 infants 22-43 weeks Nicholson et al : 376,000 Swedish infants 28-40 weeks Breeby et al: OFC (N=29090) and Length (N=26,973) 22-40 weeks CDC Data Time period 1963-2001

27. Postnatal Growth Charts Accounts for initial weight loss Dancis: Data 1948, very small sample size in lowest weight group Ehrenkranz: Pediatrics 1999:104:280 N=1660 14-16 g/kg/d weight gain 0.9 cm/week increase length 0.35 cm/week increase OFC

28. Infant Growth References A variety of growth references were developed and and used in the U.S. since the early 1900’s

29. Stuart/Meredith Growth Charts (1946-76) Caucasian, Boston/Iowa city, small sample size NCHS growth charts (1976-1978) Cross sectional Data from NHES, NHANES, and FELs CDC produced normalized version 1978 WHO recommended international use CDC (2000) 5 cross sectional nationally representative surveys between 1963-1995 Included more breast fed infants WHO (2006) Data from Brazil, Ghana, India, Norway, Oman and USA Multiethnic, affluent Exclusive breastfeeding to 4 months Solids according to recommendations 6 months Continued breastfeeding to 12 months Growth references: timeline

30. Growth Charts • CDC/NCHS • http://www.cdc.gov/growthcharts/ • World Health Organization • http://www.who.int/childgrowth/en

31. NCHS growth charts: Concerns • Infant data: Fels study • Primarily formula fed • Underrepresented groups: largely caucasian, middle class • Intervals of measurements (q3 months from 3-36 months) may not define dynamic patterns during rapid growth phases • Statistical smoothing proceedures

32. CDC Growth Charts (compared to older NCHS • Standardized data collection methods • Expanded sample • More breastfed infants • Exclusions • VLBW infants • NHANES III weight data for >6 year olds

33. CDC/NCHS Growth Charts • Clinical charts for infancy for girls and boys: • weight • length • weight for length • OFC • Choice between outer limits at 3rd and 97th or 5th and 95th percentiles

35. WHO Child Growth Standards • Released new growth standards April 2006 • Assumed that infants and children between birth and 5 years grow similarly when needs are met. • Concerns for CDC charts included: • Frequency of growth measures during dynamic periods of infant growth • Statistical methods

36. Standard vs Reference • Released new growth standards April 2006 • Assumed infants and children grow similarly when needs are met. • Concerns for CDC charts included: • Frequency of growth measures during dynamic periods of infant growth

37. WHO growth charts • Full term low birthweight infants not excluded • Birth to 2 years • N 1743 ----- 882 • 2-5 years • N 6669

42. WHO v.s. CDC • Infancy • WHO mean > CDC mean birth-6 months • “healthy breastfed infants track weight/age along WHO but falter on CDC” • Cross at 6 months and WHO mean < 6months

43. WHO v.s. CDC • CDC • Heavier, shorter • WHO • taller • WHO • Higher estimates of overweight • Lower estimates of underweight, undernutrition

46. CDC Recommends use of WHO growth standard • 2006 convened expert panel of NIH and AAP to review scientific evidence and use of WHO growth charts in clinical US settting • September 2010 recommended use of WHO charts for infants birth to 2 years

47. CDC Recommendations for infant growth charts • http://www.cdc.gov/growthcharts • Use WHO charts from birth-24 months • CDC charts for > 24 months • As a screen, 3rd and 97th percentile on WHO corresponds to 5th-95th on CDC • Clinicians should be aware that fewer individuals will be screened as “underweight” and more as “overweight” using WHO

48. Controversies/Issues • Screen vs assessment • Standard vs reference • Typical vs ideal growth • Environmental influence • Variety of diets may result in acceptable growth and nutrition status • Normal population divesity • Plot individuals on both CDC and WHO. Does your assement change? Absolute size vs pattern

49. Alterations in Growth • SGA • LGA • Preterm birth • Failure to grow (FTG)

50. SGA Infant • < 10th percentile • Symmetric vs asymmetric • Not a part of natural diversity or genetically determined • Placental insufficiency limiting nutrient supply to fetus