The New WHO growth charts - Hamilton Family Health Team

The New WHO growth charts2006 WHO Child Growth Standards (0-5 years old)2007 WHO Growth Reference (5-19 years old)1

Outline•2006 WHO Child Growth Standards vs.CDC•Use of BMI in pediatric populations•2007 WHO Growth reference•Interpreting the WHO growth charts•What to expect?•Tools and resources2

WHO Child Growth Standards (0 – 5 yrsold)• The Multicentre Growth Reference Study(MGRS) – Brazil, Ghana, India, Oman, USA• Optimal conditions◦Breastfeeding◦Non-smoking mother◦Accessible healthcare◦Complementary feeding after 6 months (GlobalStrategy for Infants and Young Children FeedingGuidelines)3

WHO Child Growth Standards• Environmental vs. genetics as the principaldeterminant of growth disparity◦Difference among countries – 3%◦Individual variance – 70%• Standard vs. reference• Windows of Achievement Timeline - 6 key motordevelopment milestones• BMI charts for infants to (0-5 years)4

WHO 2006 Standards Multi-country Predominantlybreastfed Longitudinal (i.e. eachinfant measured 21x) Use of z-scores andcorrespondingpercentiles BMI charts for infantsCDC 2000 Reference Single country Formula + breastfed(50%), 33% >3mths Cross sectional (i.e.measured once) Use of percentiles BMI is notrecommended lessthan 2 years old5

The use of z-score vs. percentiles•Percentiles◦Child’s position within the reference population•Z-scores (Standard deviation scores)6

Comparing z-scores and percentilesZ-scoreRounded percentile3 99th2 97th1 85%0 50%-1 15%-2 3rd-3 1st8

Comparing z-scores and percentiles•Percentiles are less useful in describingextremes of a distribution•Z-score values correspond to similarchanges regardless of which part of of thedistribution•14 y.o, weight increased from 95 -110-125 kg◦Percentile: 99.3 th ….99.7 th …99.9 th◦Z-score: 2.47…2.82…3.089

Comparing z-scores and percentiles•WHO recommends use of z-scores overpercentiles•Canadian-WHO charts include 0.1 to99.9 th percentiles◦Better detects extreme underweight or obesity•Stayed tune!!10

BMI (0 to 2 years)• Canada has yet to adopt use of BMI in infants• Canada-WHO BMI charts available only forages 2-19 years• Most studies for BMI done in children 2 yearsand older• Less evidence that BMI for age is better thanweight-for-age or weight-for-length12

Pediatric BMI– Issues To Consider•Identification of overweight and obesity◦Not a diagnostic criteria for classifying children◦Screening tool – guide for further assessmentor intervention•Identification of underweight or FTT (new)◦Based on adult cut-offs◦Correlation between BMI and lean body massless established13

Pediatric BMI– Issues to Consider•Adiposity rebound◦BMI for age declines after 1 year of age andfalls to a minimum at 4-6 years old◦Increase in BMI before 4-6 years old isassociated with obesity in adulthood14

Pediatric BMI– Issues To Consider•Responding to over-nutrition identified byBMI◦Weight loss not recommended◦Rather, goal is to “slow down rate of weightgain”, “allow height to catch up”15

2007 WHO Growth Reference (5 – 19 yrs)•Similar study to WHO Child GrowthStandards not feasible•Revision of data (1977 NCHS/WHO)•Data from 1963 – 1974 (American data)•2000 CDC data not included to reduceinfluence of rising obesity16

2007 WHO Growth Reference (5 – 19 yrs)•Match of curve with WHO Child GrowthStandards• Cut-off corresponds to adult BMI◦Overweight: 85 th % …. BMI 25◦Obese: 97 th % …. BMI 30•A better reference17

What to expect?•Transition to WHO Child GrowthStandards•Children on WHO growth chart aregenerally taller and leaner than CDC18

What to expect?•Canadian Regional Database•More infants (0-6mths) screened asunderweight◦Breastfed infants gain weight faster thanformula-fed infants; WHO curve shifts upward◦After that, it’s the reverse•Higher stunting rates19

What to expect?•More children classified as overweight orobese•Lower prevalence of wasting20

Using the growth charts•Based on immunization schedule,additional visits within first month and at 9months (i.e. 1-2weeks, 1,2,4,6,9,12,18,24 months and4-6 yrs)•Pre-term infants (

Interpreting growth charts•Serial measurements more meaningfulthan single reading•Trajectory towards vs. away from themean (i.e. 50 th %tile)Direction of serial measurements more importantthan actual percentile22

Interpreting growth charts•Percentile positions of variousanthropometric measures (i.e. length,weight, head circ.) are quite similar•Do not wait until curve crosses 2 or morepercentiles◦WHO percentile curves are further apart23

Tools and Resources24

WHO Growth Charts•Copies accessible from:http://www.dietitians.ca/resources/resourcesearch.asp?fn=view&contentid=1451725

ReferencesCorby L, Secker D. Growth Monitoring of Infants and Children Using the 2006 World HealthOrganizaion [WHO] Child Growth Standards and 2007 WHO Growth References –Questions and Answers for Health Professionals. Current Issues- The Inside Story. 2010.Available from: http://www.dietitians.ca/members_only/backgrounders.aspDietitians of Canada, Canadian Paediatric Society, The College of Family Physicians ofCanada and Community Healthy Nurses of Canada. The Use of Growth Charts forAssessing and Monitoring Growth in Canadian Infants and Children. Can J Diet Prac Res2004; 65:22-32.Dietitians of Canada, Canadian Paediatric Society, The College of Family Physicians ofCanada and Community Healthy Nurses of Canada. Promoting Optimal Monitoring of ChildGrowth in Canada: Using the New WHO Growth Charts. 2010. Available from:http://www.dietitians.ca/pdf/Growth_Charts_DC_full_report_Feb10.pdfWorld Health Organization. What are the WHO Child Growth Standards?. Available from:http://www.who.int/nutrition/media_page/backgrounders_1_en.pdfWorld Health Organization. What Impact Will the WHO Child Growth Standards Have?.Available from: http://www.who.int/nutrition/media_page/backgrounders_2_en.pdfWorld Health Organization. WHO Child Growth Standards and Infant and Young ChildrenFeeding. Available from: http://www.who.int/nutrition/media_page/backgrounders_3_en.pdfWorld Health Organization. Training Course on Child Growth Assessment. 2008. Availablefrom: http://www.who.int/childgrowth/training/en/26

Useful links from DC•Health Professional’s Guide to Using theWHO growth chartshttp://www.dietitians.ca/pdf/DC_HealthProGrowthGuideE_BW.pdf•Handout for parentshttp://www.dietitians.ca/pdf/DC_ChildGrowParentsE_BW.pdf27

More useful links from WHO•Investigating causes of under- or overnutritionhttp://www.who.int/childgrowth/training/jobaid_investigating_causes.pdf•Training Module and other toolshttp://www.who.int/childgrowth/training/en/28