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ANTHROPOMETY CHILDREN UNDER 5 Lecture X: Title of the Presentation -Name of Presenter INTRODUCTION : ANTHROPOMETY CHILDREN UNDER 5 • ANTHROPOMETRY is the measurement of the human body. • Anthropometric measures are used to assess the nutritional status of individuals and population groups, and as eligibility criteria for nutrition support programs. Common anthropometric measures are – Height, – Weight and – Mid-upper arm circumference (MUAC) INTRODUCTION: ANTHROPOMETRIC INDICES • When body measurements are compared to a reference value, they are called nutrition indices • Nutrition indices include – height-for-age (HFA), – weight-for-age (WFA), – weight-for-height (WFH), and – MUAC-for-age. INTRODUCTION: NUTRITION INDICATORS • Nutrition indicators are an interpretation of nutrition indices based on cutoff points – Nutrition indicators measure the clinical phenomena of malnutrition and are used for making a judgment or assessment – a good nutrition indicators detects as many people at risk as possible (sensitivity) without including too many people who are not at risk (specificity) – A good nutrition indicator should also be functionally meaningful (i.e. related to risk of morbidity and mortality), and be sensitive to change – Standard cutoff points are used internationally to define undernutrition in children 6-59 months. – The cutoff points for nutrition indicators are derived from the WHO child growth standard population (WHO standards) or NCHS reference population (NCHS population). OVERVIEW OF METHODOLOGY: BUILDING BLOCKS OF ANTHROPOMETRY The commonly used building blocks or measures used to undertake anthropometric assessment are: 1) Sex 2) Age 3) Weight 4) Length or Height 5) Mid-upper-arm Circumference (MUAC) • • • • Each provides one piece of information When used together they can provide important information about a person’s nutritional status When > 2 of these variables are used together they are called an index These indices are commonly used: WA, HA & WH. OVERVIEW OF METHODOLOGY: AGE DETERMINATION • Age determination is required for – Sampling – Deciding on whether the child is measured standing or reclining for height or length – Converting height and weight into the standard indices OVERVIEW OF METHODOLOGY: WEIGHT MEASUREMENT • Body weight indicates combined mass of all body compartments (fat, fat-free mass, water, skeleton) • Spring scales are the most common scale available • Whatever equipment is chosen, staff needs training to ensure its proper use & care • Regular validation of the weighting scale is very important. OVERVIEW OF METHODOLOGY: WEIGHT MEASUREMENT • Salter Scale for weighing infants & young Children • Can Measure up to 25 kg • Accuracy 100 gm Anthropometric indications measurement guide FANTA, 2003 OVERVIEW OF METHODOLOGY: LENGTH/HEIGHT MEASUREMENT • Length/height indicates linear growth • A measuring board should be lightweight, durable and have few moving parts • Length/height boards should be designed to measure children under 2 years of age lying down (recumbent) and older children standing up • Several types of length and height boards are available • Adequate training both in using the equipment and in providing appropriate information for the caregivers. OVERVIEW OF METHODOLOGY: LENGTH MEASUREMENT USING LENGTH BOARD Children under 2 yrs • <85 cm tall • Too ill to stand • Accuracy 0.1 cm Measuring length requires experience & patience Anthropometric indicators measurement guide FANTA.2003 OVERVIEW OF METHODOLOGY: HEIGHT MEASUREMENT USING HEIGHT BOARD • • • Children > 2 yrs > 85 cm tall Accuracy 0.1 cm Length may be up to 0.5 cm more than corresponding height Anthropometric indicators Measurement guide FANTA, 2003 OVERVIEW OF METHODOLOGY: MUAC MEASUREMENT • Is relatively easy to measure • Use for rapid screening of acute malnutrition from the 6-59 months age range • A good predictor of immediate risk of death • MUAC is also recommended for assessing adult undernutrition and for estimating prevalence of undernutrition at the population level • Color coded and or graduated MUAC tapes are available Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: MUAC MEASUREMENT • 6 mo – 5 yrs • < 12.5 cm acute malnutrition Anthropometric indicators Measurement guide FANTA, 2003 Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: Indices reflect about the nutritional status of infants & children Weight for-age: - Low WFA identifies underweight, for a specific age & sex - Reflects both past (chronic) &/or present (acute) undernutrition - Unable to distinguish between the two Height for-age: - Low HFA identifies past or chronic undernutrition (stunting) - Stunting indicates reduced linear growth - Cannot measure short-term changes in malnutrition - For children <2 yrs of age, the term is length-for-age/LA - For children > 2 yrs age, the index is referred as height-for-age/HA Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: Indices reflect about the nutritional status of infants & children Weight for-height: - Low WFH identifies current or acute undernutrition (wasting) - Useful when exact age is difficult to determine - Weight for-length (< 2 yrs) or weight for-height (in > 2 yrs) - Appropriate for examining short-term effects Mid- Upper Arm Circumference (MUAC): - Low MUAC (<12.5 cm) indicates acute malnutrition among children 659 months - Is relatively easy to measure and a good predictor of immediate risk of death - Is used for rapid screening of acute malnutrition Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: USE OF NUTRITION INDICES Measure or Index WFA HFA Nutritional Condition UNDERWEIGHT ( composite measure of stunting and wasting) To assess changes in the magnitude of malnutrition over time STUNTING (Past growth failure; • associated with a number of long-term factors including chronic insufficient protein and energy intake, frequent infection, sustained inappropriate feeding practices and poverty etc.) WFH Usefulness of Index • • Problem analysis in designing interventions Evaluation of program preferably for children under 2 years of age not for monitoring as it does not change in the short term such as 6-12 months WASTING ( current or acute • Screening or targeting purposes as malnutrition resulting from failure to gain weight or weight loss. Causes includes inadequate food intake, incorrect feeding practices, disease, and infection or, more frequently, a combination of these factors.) wasting in individual children and population groups can change rapidly and shows marked seasonal patterns associated with changes in food availability or disease prevalence to which it is very sensitive. • Annual reporting Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: USE OF NUTRITION INDICES Measure or Index Nutritional Condition Usefulness of Index MUAC WASTING • Rapid screening of acute malnutrition from the 6-59 month age range • Assessing acute adult undernutrition and • Estimating prevalence of undernutrition at the population level Odema (presence of excessive amounts of fluid in the intracellular tissue) Clinical sign of severe malnutrition • Screening and Surveillance Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: REFERENCES • To standardize a child’s measurement to compare individual value with the median/mean of same age & sex • Taking age & sex into consideration, difference in measurements can be expressed as: - standard deviation (SD) or Z-score - percentage of the median - percentile (least useful in clinical practice) [Z-score is preferable; percentage may be used ] Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: SD Score or ZScore • A SD score is also called a Z-score and is defined as the deviation of an observed individual value from the median value of the reference population. • A Z-score is the number of standard deviations (SD) below or above the reference median value (WHO/UNICEF definition, 2009). The median is the middle value in a set of values. It is one type of ‘average’ • The Z-score or standard deviation unit (SD) is defined as the difference between the value for an individual and the median value of the reference population for the same age or height, divided by the standard deviation of the reference population. This can be written in equation form as: Z-score (or SD-score) = (observed value) – (median reference Value) standard deviation of reference population Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: SD Score or ZScore • • • • Z-score can be used to indicate how far a child’s weight is from the median weight for that child’s height (the standard deviation or SD) The concept of a normal distribution is important for understanding what a Z-score is. In a normal distribution, most values are grouped around the middle, or “normal” A Z-score gives an image of how far a child is from “normal” or the median The weights of all boys or all girls of a certain height fall into a normal (or almost normal) distribution. When the weights are graphed, the result resembles a normal bell-shaped curve. + + + Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: SD Score or ZScore • Z-scores are more commonly used by the international nutrition community because they offer two major advantages • First , using Z-scores allow us to identify a fixed point in the distribution of different indices and across different ages • The second major advantage of using Z-scores is that useful summary statistics can be calculated from them; mean and standard deviation to be calculated for the Z-scores for a group of children. Lecture X: Title of the Presentation -Name of Presenter OVERVIEW OF METHODOLOGY: REFERENCES • The median is the value at exactly the midpoint between the largest and smallest. The percentage of the median is defined as the ratio of a measured or observed value in the individual to the median value of the reference data for the same age or height for the specific sex, expressed as a percentage. This can be written in equation form as: Percent of median = observed value x 100 median value of reference population • The percentile is the rank position of an individual on a given reference distribution, stated in terms of what percentage of the group the individual equals or exceeds. OVERVIEW OF METHODOLOGY: SD Score or ZScore • A comparison of cutoffs for percent of median, percentile and Z-scores illustrates the following: Z-score Percent of median Percentile -3 70% 0.13 -2 80% 2.28 -1 90% 15.8 OVERVIEW OF METHODOLOGY: REFERENCE STANDARD Bangladesh has adopted the new World Health Organization (WHO) Growth Reference Standard (GRS), Which should be used for determining the WHM and WHZ. OVERVIEW OF METHODOLOGY: TYPES OF UNDERNTURITION • Undernutrition is defined as lack of nutrients caused by inadequate dietary intake and/or disease. It compasses a range of conditions, including – – – – Acute malnutrition Chronic malnutrition Underweight Micronutrient deficiency • Undernutrition is defined based on anthropometric indicators, clinical signs and clinical tests. OVERVIEW OF METHODOLOGY: Different forms of undernutrition Definition INDEX or MEASURE MODERATE SEVERE HFA <-2 and > -3 z-score <-3 z-score WFH <-2 and > -3 z-score <-3 z-score MUAC (6-59 months) <125 mm and > 115 mm <115 mm MUAC (6-59 months) <-2 and > -3 z-score <-3 z-score WFA <-2 and > -3 z-score <-3 z-score Stunting reflects chronic malnutrition Inadequate length or height* relative to age Wasting reflects acute malnutrition Inadequate weight relative to length or height* Inadequate muscle tissue and fat stores in the body Underweight reflects both chronic and acute malnutrition. Inadequate weight relative to age Bilateral Pitting Oedema reflects severe acute malnutrition An accumulation of fluid that starts in both feet and that can progress to other parts of the body Any bilateral pitting oedema indicates severe acute malnutrition OVERVIEW OF METHODOLOGY : ACUTE MALNUTRITION • Acute malnutrition caused by a decrease in food consumption and/or illness resulting in bilateral pitting oedema or sudden weight loss. • It is defined by the presence of bilateral pitting oedema or by wasting OVERVIEW OF METHODOLOGY: Types of Acute Malnutrition Severe Acute Malnutrition (SAM) • is defined by the presence of bilateral pitting or severe wasting • a child with SAM is highly vulnerable and has a high mortality rate Moderate Acute Malnutrition (MAM) • is defined by moderate wasting Overview of Methodology : Reference Cutoff Values for SAM & MAM Bilateral pitting MUAC oedema WFH z-score (WHO standards or NCHS references) WFH as a percentage of the median (NCHS references) SAM : Present <115 mm or red <-3 <70% MAM : Not present >110 mm and <125 mm or yellow > -3 and <-2 > 70% and <80% METHODS OF DATA COLLECTION • Community level screening e.g. GMP • Household visits • Survey METHODS OF DATA ANALYSIS • Use computer software like e.g. Epi Info, ANTHRO, SPSS etc. – – – – – – – Prevalence of malnutrition Recovery rate Death rate Defaulter rate Non-responder rate Average length of stay Average weight gain per kg/day VALIDITY AND RELIABILITY : WHO child growth standards and the identification of severe acute malnutrition in infants and children Using weight-for-height • • WHO and UNICEF recommend the use of a cut-off for weight-for height of below 3 standard deviations (SD) of the WHO standards to identify infants and children as having SAM. The commonly used cut-off is the same cut-off for both the new 2006 WHO child growth standards (WHO standards) as with the earlier National Center for Health Statistics (NCHS reference). The reasons for the choice of this cut-off are as follows: 1) 2) 3) 4) Children below this cut-off have a highly elevated risk of death compared to those who are above; These children have a higher weight gain when receiving a therapeutic diet compared to other diets, which results in faster recovery; In a well-nourished population there are virtually no children below -3 SD (<1%). There are no known risks or negative effects associated with therapeutic feeding of these children applying recommended protocols and appropriate therapeutic foods. VALIDITY AND RELIABILITY : WHO child growth standards and the identification of severe acute malnutrition in infants and children Using MUAC • • • • • WHO standards for mid-upper arm circumference (MUAC)-for-age show that in a well nourished population there are very few children aged 6–60 months with a MUAC less than 115 mm. Children with a MUAC less than 115 mm have a highly elevated risk of death compared to those who are above. Thus it is recommended to increase the cut-off point from 110 to 115 mm to define SAM with MUAC. When using the WHO child growth standards to identify the severely malnourished among 6–60 month old children, the below -3SD cut-off for weightfor-height classifies two to four times as many children compared with the NCHS reference. The prevalence of SAM, i.e. numbers of children with SAM, based on weight-for height below -3 SD of the WHO standards and those based on a MUAC cut-off of 115 mm, are very similar. The shift from NCHS to WHO child growth standards or the adoption of the new cut-off for MUAC will therefore sharply increase case loads. This has programmatic implications. Conclusion • Advantages of anthropometry Simple, safe, cheap, non-invasive, portable requires minimal training • Limitations of anthropometry Cannot identify specific deficiencies, fairly slow to respond to recent changes in nutritional status Conclusion USE OF ANTHROPOEMETRY • Identify individuals & populations with normal & abnormal nutritional status • Predict who will benefit from interventions • Identify social & economic inequity • Evaluate response to interventions. Lecture X: Title of the Presentation -Name of Presenter Thank You Lecture X: Title of the Presentation -Name of Presenter