08 VS Measurement approaches malnutrition · malnourished children • Children with a MUAC
Transcript of 08 VS Measurement approaches malnutrition · malnourished children • Children with a MUAC
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MALNUTRITIONMEASUREMENT APPROACHES
Dr. Veronika Scherbaum, 2008
reflects individual‘s healthas influenced by food intake/utilisation and subsequent levels of nutrients
WHY DO WE NEED TO MEASURE IT?- Provides baseline information- Determines areas of high risk / priority
- Essential for planning nutrition policies
- Useful for evaluating nutrition programmes
NUTRITIONAL STATUS
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HOW DO WE MEASURE the nutritional status?
• Anthropometry• Dietary• Clinical• Biochemical
investigations
ANTHROPOMETRIC ASSESSMENT at individual / family level
• How severely malnourished is this child/adult?
• How fast is this child/adult responding to nutritional rehabilitation (GMP)*?
• How many malnourished people are in one family?
• Affected age group?
•Growth Monitoring Programme
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ANTHROPOMETRIC ASSESSMENT at population level
AT NATIONAL LEVEL- representative results
of all regions- trend assessment- for long term planningDemographic health survey (DHS)
FOR CERTAIN POPULATION GROUPS- under circumstances of food crises- nutrition baseline survey (NGOs)- evaluation of the progress / change as a result of an
intervention (nutritional surveillance)
DEFINITION OF ANTHROPOMETRY
„a technique that uses human body measurementsto draw conclusions about the nutritional status of individuals and populations“
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ANTHROPOMETRIC Assessment
VARIABLES
• Age (months)• Weight (kg)• Length ≤ 85 cm /
Height > 85 cm
• MUAC (cm)
• Sex
INDICES
• Weight-for-age• Length/height-for-age• Weight-for-length/height
• Body-Mass-Index/age
• MUAC-for-age
• Sex – WFA, etc
WIDLY USED NUTRITIONAL INDICES IN CHILDREN (< 5 years)
LENGTH / HEIGHT-FOR-AGE- reflects skeletal growth, past/chronic
malnutrition, stunting
WEIGHT-FOR LENGTH / HEIGHT- indicates acute weight loss, wasting
(useful in emergencies when age is not known)
WEIGHT-FOR-AGE- identifies underweight caused by either
wasting or stunting or a combination of both (useful in clinics and GMPs)
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WEIGHT – FOR – AGE REFERENCE DATA (US-NCHS*)
(* US – National Centre for Health Statistics)
WHO, 2006
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Types of scale used
ENN 29, 2006
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LIMITATIONS:- Clothing not defined
- Scale not at eye level
- Clinical signs of PEM e.g. distended abdomennot recognized
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REASONS FOR EXCLUSION OF CHILDREN < 6 MONTHS
• Thought to be protected by breast feeding
• Anthropometric measurements are influenced by birth weight
• Reference population (NCHS) wasless applicable because reference infants were virtually all bottle-fed
• Survey staff is hesitant to weigh and measure young infants
• Imprecision in measurements is larger as proportion of measurement (+/- 100 g)
Reasons for exclusion of infants < 6 months
a swinga trouser
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A rod
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„Road to health“ Chart
LIMITATIONS OF WEIGHT-FOR-AGE IN EMERGENCIES
• Age of the child is often unknown
• WFA measures chronic and acute malnutrition
• Lack of skilled staff for interpretation of individual weight and follow-up (GMP)
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STUNTING
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WASTING
Age in months
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CALCULATING NUTRITIONAL INDICES
An individual child‘s measurement (e.g. weight)is compared with the expected value of a child of the same age from a reference population and presented as:
• A percentage of the expected measurement (percentage median)
• A standard deviation-score (z-score) in relation to the median
• As percentiles
W/H wasting
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Z-Score is a standardized measure of the distance of an observation from the mean of a distribution
The z-value =observation – mean
divided by SD of the reference population
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Percentage of median = observed value divided byMedian reference value x 100It is popular in clinical settings (e.g. road to health growth chart)because it is straight forward to interpret
<60% <7
5%
<60%
100%
<75%
<90%
Height
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www.fantaproject.org, 2006
WASTING: ACUTE MALNUTRITION
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Severe
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PREVALENCE (%) OF STUNTING, UNDERWEIGHT AND WASTING
children < 5 years, 1995-2003
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101520253035404550
Africa South Asia Latin Am All DC
Stunting Underw
Wasting
Seasonality of acute malnutrition of children (0-59 mo) in Bangladesh
HKI, 1999
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-2
-1.5
-1
-0.5
0
0.5
0 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59
Africa Latin America and Caribbean Asia
Global weight-for-age Z-scores (underweight)W
AZ-
scor
es
Age
Source: Shrimpton, R. et al, 2001. http://www.pediatrics.org/cgi/content/full/107/5/e75
0 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59
Global height-for-age Z-scores (stunting)
HA
Z-sc
ores
Age
-2.5
-2
-1.5
-1
-0.5
0
0.5
Africa Latin America and Caribbean Asia
Source: Shrimpton, R. et al, 2001. http://www.pediatrics.org/cgi/content/full/107/5/e75
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60 million wasted
The timing of growth failure
130 million underweight150 million stunted
Window of opportunity
R. Shrimpton (data from 39 studies)
Prevalence of stunting, under-weight, and wasting (<-2 SD) in children in Latin America and the
Caribbean
05
101520253035404550
Bolivia
BrazilColombia
Dominican Rep
Ecuador
HaitiEl Salvador
Guatemala
Mexico
Nicaragua
Peru
Prev
alan
cia
22
00
1010
2020
3030
4040
5050
0 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
VULNERABLEAGE
VULNERABLEAGE
PercentPercent
Note: Stunting reflects chronic malnutrition; wasting reflects acute malnutrition;underweight reflects chronic or acute malnutrition, or a combination of both. Plotted values aresmoothed by a five month moving average.
Note: Stunting reflects chronic malnutrition; wasting reflects acute malnutrition;underweight reflects chronic or acute malnutrition, or a combination of both. Plotted values aresmoothed by a five month moving average.
Source: Demographic Health SurveysSource: Demographic Health Surveys
Age (Months)Age (Months)
Stunting, Underweight and Wastingin Bolivia
Low height / ageLow height / age
Low weight / ageLow weight / age
Low weight-for-heightLow weight-for-height
S Fishman et al., CQHR, Vol 1, WHO 2004
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WHO Global database on Child growth and Malnutrition, 2002
Prevalence of stunted children indeveloping countries
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MID-UPPER-ARM CIRCUMFERENCE
Development of MUAC for age growth reference data
Bull World Health Org 1997, 75: 11-18
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Observed relationship
between MUAC and child
mortality in five studies
Food and Nutrition Bulletin, Vol 27, 3 (suppl), 2006
To find midpoint between tip of shoulder and elbow
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MUAC – SCREENING in children
• To identify potentially malnourished children
• Children with a MUAC <12.5 cm are referred to further measurementsand may be eligible for supplementary (WFH<80%, <-2 z-score) or therapeutic feeding(WFH<70%, <-3 z-score)
MUAC-based selection methods
Food and Nutrition Bulletin, Vol 27, 3 (suppl), 2006
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MID-UPPER-ARM CIRCUMFERENCE
ADVANTAGES- Rapid screening
- Less equipment required
- MUAC-FOR-AGE
DISADVANTAGES- Measurement errors- Deciding if a child is
between e.g. 1 and 5 years old
- Variable cut-off points are usede.g. <12.5cm, <11.5cm<11cm for severe malnutrition
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MUAC SCREENING in ADULTS
MUAC (cm) FEMALELeft arm≥ 23 normal21-23 moderate< 21 severe
malnourished
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BODY-MASS-INDEX (BMI) ASSESSMENTWeight (kg) / height2 (m2)
To be used between 20-65 yearsBMI / AGE during adolescence
BMI <16 Severe malnutrition16.0-16.9 Moderate malnutrition17.0-18.5 Mild malnutrition18.6-19.9 Possibly malnourished20.0-24.9 Healthy25.0-29.9 Overweight30.0-34.9 Pre-obese≥ 35 Obese
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SEVERITY INDEX BASED ON BMI
BMI < 18.5 NUTRITIONAL SITUATION
5 – 9.9% low risk → monitoring10 – 19.9% moderate risk → attention20 – 39.9% serious situation → action≥ 40% very critical situation
→ immediate relief action