Out with the old? In with the new? Implications of the new WHO 2006 Child Growth Standards Alison Tumilowicz, Ph.D. Megan Deitchler, MPH CORE Elluminate Session July 27, 2006 1 How Growth References are Commonly Used Individual Level: Assess the growth of an individual child Growth monitoring/promotion Screening for interventions Population Level: Assess the health and well-being of a population Targeting communities for interventions 2 Presentation Outline 2. NCHS 1978 Child Growth References 3. WHO Multicentre Growth Reference Study
4. WHO 2006 Child Growth Standards 5. Comparison of WAZ at the Individual Level 5. Differences Between the NCHS 1978 and the WHO 2006 Weight-for-Age (WFA) Growth Curves 6. Comparison of WAZ, WHZ, and HAZ at the Population Level 7. Implications for Monitoring, Evaluation and Reporting 3 NCHS 1978 Child Growth References 4 NCHS 1978 Child Growth References Adopted in 1978 by
WHO as the international reference for: Weight-for-age Weight-for-length/height Length/height-for-age 5 NCHS 1978 Child Growth References Garza and de Onis. 2004. Food and Nutrition Bulletin, vol 25, no.1 (supplement 1), p. S6. 6 WHO Multicentre Growth Reference Study (1997-2003) 7 WHO Multicentre Growth Reference Study de Onis et al. 2004. Food and Nutrition Bulletin, vol 25, no.1 (supplement 1), p. S15. 8 WHO Multicentre Growth Reference Study Selection criteria used to select samples and
construct WHO child growth standards: Minimal health, environmental, and economic constraints on growth Full-term, single birth Absence of significant morbidity Non-smoking mother Optimal infant and child feeding practices Longitudinal Sample 0-24 m (n=882): a. Exclusively breastfed or predominantly breastfed for at least 4 m b. Continued breastfeeding for at least 12 m c. Introduction of complementary feeding by 6 m Cross-sectional sample 18-71 m (n=6669): a. Minimum of 3 m of any breastfeeding 9 WHO 2006 Child Growth Standards
10 WHO 2006 Child Growth Standards Available now: To be available: Weight-for-age Weight-for-length/height Length/height-for-age Body mass index-for-age Windows of milestone achievements MUAC-for-age Head circumference-for-age Triceps skinfold thickness-for-age Subscapular skinfold thickness-for-age 11 WHO 2006 Child Growth Standards WHO Child Growth Standards Website: http://www.who.int/childgrowth/en/ Standards Training course Anthropometric software Publications
12 Comparison of WAZ at the Individual Level 13 Case Study: Sara Saras age Saras weight (kg) 0m 2.4 1m 3.5 3m 4.5 6m 5.4 9m 6.0
11 m 6.4 NCHS 1978 WAZ score WHO 2006 WAZ score 14 At what age does Sara cross -2 SD using the NCHS 1978 WFA growth curve? 12 NCHS Weight (kg) 10 median 6m -1 SD 8 -2 SD
-3 SD 6 4 -2.08 2 0 0 2 4 6 Age (m) 8 10 15 At what age does Sara cross -2 SD using the WHO 2006 WFA growth curve? 12 WHO 10
median 3m Weight (kg) 8 -1 SD -2 SD -3 SD 6 4 -2.05 2 0 0 2 4 6 Age (m)
8 10 16 Case Study: Sara Saras age Saras weight (kg) NCHS 1978 WAZ score WHO 2006 WAZ score 0m 2.4 -1.68 -1.99 1m 3.5 -0.81 -1.26
3m 4.5 -1.21 -2.05 6m 5.4 -2.08 -2.50 9m 6.0 -2.65 -2.65 11 m 6.4 -2.78 -2.60
17 Differences Between the NCHS 1978 and the WHO 2006 Weight-for-Age (WFA) Growth Curves 18 NCHS 1978 and WHO 2006 WFA Growth Curves GIRLS WEIGHT-FOR-AGE 0-11 m 10 NCHS 9 median -1 SD WHO 8 -2 SD -3 SD Weight (kg) 7 6
5 4 3 2 1 0 0 2 4 6 Age (m) 8 10 19 GIRLS WEIGHT-FOR-AGE 0-5 m 10 9 NCHS 8 WHO median
Weight (kg) 7 6 -1 SD 5 -2 SD 4 -3 SD 3 2 1 0 0 1 2 3 4 5
Age (m) Saras age Saras weight (kg) NCHS 1978 WAZ score WHO 2006 WAZ score 0m 2.4 -1.68 -1.99 1m 3.5 -0.81 -1.26 3m 4.5
-1.21 20 -2.05 GIRLS WEIGHT-FOR-AGE 6-11 m 10 9 8 NCHS median WHO -1 SD -2 SD -3 SD Weight (kg) 7 6 5 4 3 2 1 0 6
7 8 9 Age (m) 10 11 NCHS 1978 WAZ score WHO 2006 WAZ score Saras age Saras weight (kg) 6m 5.4 -2.08 -2.50 9m 6.0
-2.65 -2.65 11 m 6.4 -2.78 -2.60 21 NCHS 1978 and WHO 2006 WFA Growth Curves GIRLS WEIGHT-FOR-AGE 0-59 m 20 NCHS 18 Weight (kg) median WHO 16 14
-1 SD 12 -2 SD 10 -3 SD 8 6 4 2 0 0 5 10 15 20 25 30 35
40 45 50 55 Age (m) 22 Comparison of WAZ, WHZ, and HAZ at the Population Level 23 Differences in the Prevalence of Underweight Case Study: Malawi (DHS 2000) Children 0-59 m % children WAZ score <-2 SD NCHS 1978 WHO 2006 Change 0-5 m
4.1 11.8 +7.7 6-11 m 22.4 21.2 -1.2 12-23 m 33.6 22.4 -11.2 24-35 m 29.0 21.5 -7.5 36-47 m
19.9 15.2 -4.7 48-59 m 19.4 16.3 -3.1 Total 0-59 m 23.3 18.6 -4.7 24 Differences in Mean WAZ Score Case Study: Malawi (DHS 2000) Children 0-59 m 2.5 2 Mean WAZ score 1.5
1 0.5 WHO NCHS 0 -0.5 -1 -1.5 -2 -2.5 0 6 12 18 24 30 36 42 48 54 Age in months
Source: FANTA/AED, June 2006 Note: Means estimated using a 5 month moving average 25 Differences in the Prevalence of Wasting Case Study: Malawi (DHS 2000) Children 0-59 m % children WHZ score <-2 SD NCHS 1978 WHO 2006 Change 0-5 m 4.4 10.8 +6.4 6-11 m 8.7 14.0
+5.3 12-23 m 9.2 8.0 -1.2 24-35 m 4.0 4.2 +0.2 36-47 m 2.0 2.0 +/-0.0 48-59 m 1.5 1.7
+0.2 Total 0-59 m 5.0 6.1 +1.1 26 Differences in Mean WHZ Score Case Study: Malawi (DHS 2000) Children 0-59 m 2.5 2 Mean WHZ score 1.5 1 0.5 WHO NCHS 0 -0.5 -1 -1.5 -2 -2.5 0
6 12 18 24 30 36 42 48 54 Age in months Source: FANTA/AED, June 2006 Note: Means estimated using a 5 month moving average 27 Differences in the Prevalence of Stunting Case Study: Malawi (DHS 2000) Children 0-59 m % children HAZ score <-2 SD NCHS 1978
WHO 2006 Change 0-5 m 10.6 18.5 +7.9 6-11 m 24.7 29.4 +4.7 12-23 m 55.2 56.7 +1.5 24-35 m 52.7
62.6 +9.9 36-47 m 57.4 63.7 +6.3 48-59 m 55.1 57.0 +1.9 Total 0-59 m 46.6 51.8 +5.2 28 Differences in Mean HAZ Score
Case Study: Malawi (DHS 2000) Children 0-59 m 2.5 2 Mean HAZ score 1.5 1 0.5 WHO NCHS 0 -0.5 -1 -1.5 -2 -2.5 0 6 12 18 24 30 36
42 48 54 Age in months Source: FANTA/AED, June 2006 Note: Means estimated using a 5 month moving average 29 Differences in Mean WAZ, WHZ, HAZ Scores Case Study: Malawi (DHS 2000) Children 0-59 m 2.5 2 Mean z-score 1.5 1 WAZ WHO HAZ WHO WHZ WHO WAZ NCHS HAZ NCHS WHZ NCHS 0.5 0
-0.5 -1 -1.5 -2 -2.5 0 6 12 18 24 30 36 42 48 54 Age in months Source: FANTA/AED, June 2006 Note: Means estimated using a 5 month moving average 30 Comparison of WAZ, WHZ, and HAZ
at the Population Level What factors influence the extent of the difference in the prevalence of malnutrition estimated by the NCHS 1978 references vs. the WHO 2006 standards? 1. Age distribution of sample population 2. Level of malnutrition in sample population 3. Anthropometric indicator 31 Implications for Monitoring, Evaluation, and Reporting 32 Implications of the WHO 2006 Child Growth Standards: Tips for Monitoring, Evaluation, and Reporting When using anthropometric data for M&E or reporting trends across time, the same references must be used to process the anthropometric data for all points in time
Analysts should check with host government and donor(s) about which references should be used to meet reporting requirements For clarity in program reporting: Will be important to label which reference was used for processing the anthropometric data (i.e. NCHS 1978 or WHO 2006) Programs may wish to process and report anthropometric data using both set of references until adoption of the WHO 2006 child growth standards is more widespread 33 FANTA Project www.FANTAproject.org Alison Tumilowicz [email protected] Megan Deitchler [email protected] 34
