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3

2 Anthropometry

Introduction

Anthropometrythe study and technique of human body measurement

is the most commonly used method for the assessment of two of the most

widespread nutrition problems in the world: (1) protein-energy malnutri-

tion, especially in young children and pregnant women; and (2) obesity,

or overweight, in all age-groups (Jelliffe and Jelliffe, 1989). Measure-

ments of weight, height (or length) and, less frequently, subcutaneous fat

and muscle, are the usual data collected. This chapter covers the basicindiceslow birth weight, height-for-age, weight-for-height, weight-for-

age, mid-upper arm circumference, body mass indexderived from

anthropometric measurements related to body size and composition, as

well as standard cut-offs for indicators, and their application to decision-

making at individual and population levels.

At the individuallevel, anthropometry is used to assess compromised

health or nutrition well being, need for special services, or response to an

intervention. A one-time assessment is used during emergency situationsto screen for individuals requiring immediate intervention. Under non-

emergency conditions, single assessments are used to screen for entry

into health or nutrition intervention programs either as an individual or as

a marker for a household or community at risk.

Trend assessments for individuals, such as periodic monitoring of weight

gain in children three years and younger, are used to detect growth prob-

lems, to intervene early enough to prevent growth failure, or to assess an

individuals response to some type of intervention.

At the populationlevel, anthropometric data from a single assessment

provide a snapshot of current nutrition status within a community, and

should help to identify groups at risk of poor functional outcomes in terms

of morbidity and mortality (Gorstein, et al., 1994). Under emergency con-

ditions, these static measurements are used to identify priority areas for

assistance. In non-emergency situations, one-time anthropometric

assessments are used for geographic targeting and as the basis for

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4

resource allocation decisions. Repeat survey results allow analysis of

trends, with anthropometric data possibly serving as concurrent indica-

tors of impending food shortages in the context of an early warning sys-

tem, as indication of service delivery problems or successes, and as an

indicator of population-based response to interventions.

Advantages

Anthropometric measurements are: (1) non-invasive and relatively eco-nomical to obtain; (2) objective; and (3) comprehensible to communities

at large. They produce data that can be graded numerically, used to

compile international reference standards, and compared across popula-

tions. They can also supply information on malnutrition to families and

health care workers prior to the onset of severe growth failure (or exces-

sive weight gain).

Disadvantages

The disadvantages of anthropometry lie in: (1) the significant potential for

measurement inaccuracies; (2) the need for precise age data in young

children for construction of most indices; (3) limited diagnostic relevance;

and (4) debate over selection of appropriate reference data and cut-off

points to determine conditions of abnormality (adapted from Jelliffe and

Jelliffe, 1989).

Selecting indicators and cut-off points

Task managers are frequently faced with decisions about which anthro-

pometric data should be collected and which indices constructed for a

particular purpose. They can be used as a proxy for household poverty,

to describe the overall picture of nutrition in a region or country, to deter-

mine target areas for delivery of nutrition/health interventions, to monitor

project progress or to evaluate project impact (see Box 2-1). While every

context warrants individual consideration of the range of anthropometric

indicators and an evaluation of logistical constraints and the specific

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5

objectives of the exercise, some indicators are used frequently. For ex-

ample, 2Z weight-for-age is the most common index of childhood mal-

nutrition for children under 3 years. (See Annex A for a related discussion

of indicator sensitivity and specificity and for an explanation of Z scores.)

It is important to note that each index delivers unique informationin

children, weight-for-height does not substitute for height-for-age or

weight-for-age, as each reflects a particular combination of biological

processes. Guidance on the range of uses for each indicator and targetgroup is included in the text beginning on page 13. Refer to Annex A for

summary recommendations on survey design issues for various policy-

making and program management purposes.

Box 2-1: Potential Objectives for Useof Anthropometric Indicators

Identification of individuals or populations at riskindicators

must reflect past or present risk, or predict future risk.

Selection of individuals or populations for an intervention

indicators need to predict the benefit to be derived from the

intervention.

Evaluation of the effects of changing nutritional, health, or socio-

economic influences, including interventionsindicators need to

reflect response to past and present interventions.

Excluding individuals from high-risk treatments, from employ-

ment, or from certain benefitsindicators predict a lack of risk.

(WHO Expert Committee, 1995)

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6

Measurement issues

Weight (in grams or kilograms)

Various types of scales are available to measure the weight of a child,

including spring scales (Salter) or beam balance scales. Hanging scales

are commonly used in many countries because they can be transported

easily, can be used in almost any setting (particularly where a flat surface

is not available) and are relatively inexpensive. Direct recording scaleshave been developed by Teaching Aids at Low Cost (TALC)1 where a

growth chart is inserted into the scale and a pointer indicates the spot on

the chart. A family member can mark the chart, which encourages par-

ticipation in the growth promotion activity. Balance beam scalesare com-

monly used in health centers, as they need to be positioned on a flat

surface for accurate measurement and are not easily transported.

Standing beam scalesare used to measure weight of adults, particularly

in health centers. UNICEFs UNISCALE is a new nonbeam or digital scalethat allows for the calculation of both adult and infant weight. An adults

weight is measured, then the adult accepts an infant in her/his arms on

the scale and the additional weight is automatically calculated. Standing

scales (both beam and digital) must be placed on a flat horizontal sur-

face. Weight is usually measured to the nearest 100 grams (see Table 2-1

for available measurement tools).2

1. TALC can be contacted at PO Box 49, St. Albans, Herts, UK, AL14AX. Telephone

(44 1) 727 853869, Fax (44 1) 727 846852. Information on low cost educational materi-

als, books, slide sets, and newsletters is available at www.talcuk.org.

2. Weighing scales can be procured through UNICEFs supply services in

Copenhagen. Contact the Customer Service Officer at telephone: (45) 35.27.35.27,

Fax: (45) 35.26.94.21, email: supply@unicef.dk or customer@unicef.dk, or on the web at

www.supply.unicef.dk/. UNICEF-New York telephone: 212-366-7000; fax: 212-887-7465.

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7

Anthropometric Assessment Tools

Height/Length (in centimeters)

Height is measured as recumbent length for the first two years of life.

After the age of two, a childs stature can be measured in the standing

position. Measurement of length requires a Shorr-Board or locally pro-

duced length board (specifications for constructing such a board are

available from UNICEF, CDC and others and can be constructed easily).To measure height, a fixed, non-stretchable tape measure marked by 0.5

centimeter intervals (to the millimeter is desirable), a carpenters triangle

or substitute to ensure the childs head is at a right angle to the wall, a

straight wall and an even floor surface are necessary to collect accurate

height measurements (see Table 2-1 for available measurement tools).

Arm Circumference (in centimeters)

Special tape measures (Shakir strip or insertion tape) have been devel-oped to measure arm circumference. A non-stretchable centimeter tape

or finger and thumb measurement (for children) can also be used. Mea-

suring tapes will be cut and marked differently depending upon the

population (children or women) being measured. With the arm hanging

relaxed, the circumference at the midpoint between the shoulder and

elbow is measured to the nearest 0.1 cm or the color (e.g., red indicates

severe wasting, yellow is moderate, and green signals adequate nutrition

status) on the tape noted. See Figures 2-1 and 2-2, for more detailed

information on measuring arm circumference.

Accuracy of these measurements is influenced by the type and condition

of the equipment and the qualifications and training of the individual

taking the measurements. The equipment should be routinely calibrated

by regularly measuring something of known weight or height. Measure-

ments are recorded in a health card, on a growth chart, or in another

reporting system. Detailed instructions for taking weight, height and arm

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8

Table2-1:ComparisonofDifferentType

sofMeasuringTools

Accuracy/

Advantagesand

MeasuringTool

Use

Source

Standardization

Disadvantages

Cost

Mid-ArmCircum-

Mea

suresthecircum-

UNICEF

a,andTALCb:Subjecttoobserver

Convenient,but

UNICEF:Pack

ferenceTape

ferenceoftheupper

Tapesas

wellas

error,maypull

notofmuchuse

of50for$4.25.

(MUAC)

arm

toassesscurrent

instructionsfor

tapetootight

inmeasuringarm

TALC:$0.25

nutr

itionalstatus

making

andusing

circumferencein

0.40each

theseav

ailable

childrenunderthe

ageofone.Exact

ageofchildisre-

quiredtointerpret

results.

SingleBeam

Usedtomeasure

CMSc W

eighing

Accurateandcan

Sturdy,easyread-

CMS:

clinicscales

weightsofchildren

Equipment(UK),

bestandardized

ability,canbetared,

$150300

UNICEF

a

butheavyandnot

UNICEF:$85.52

easilyportable

SingleBeam

Usedtomeasure

UNICEF

a,local

Accurateandcan

Iseasytouse,but

$1525

freehangingscales

weightofchildren

manufacturers

bestandardized

slow.Durable,good

readability,butmay

notbeveryportable.

DialSpringScales

Usedtomeasure

CMS(U

K)c

Accurateandcan

Sturdy,durable,and

$3560

weightsofvery

bestandardized

alsoportable.Canbe

youngchildren

difficulttoreadwith

and

olderchildren

aswingingneedle.

ElectronicScale

Mea

suresweight

UNICEF

a

Accurateand

Veryeasytouse.Can

$90

(UNIscale)

ofchildrenandadults

standardized

betaredtomothers

weighttomeasure

weightofinfants.

Sturdy,durableand

portable.Scaleneeds

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9

tobereplacedwhen

batteriesareexhausted

(10yearlifespan)

TALCDirect

Mea

suresgrowthof

TALCb

Veryaccuratea

nd

Sturdy,andhighly

$25

RecordingScale

childrenbydirectly

easilystandard

izable

durable,easytounder

-

reco

rdingweighton

stand(evenbynon-

achildsgrowthchart

literatepopulations).

Length/height

Usedtomeasure

Canbelocally

Shouldbeaccu

rate

Aresturdyand

Pricevariesbe-

boards

recu

mbentlengthin

manufactured(in-

andeasyto

durable,withgood

tweenlocally

childrenundertheage

structionsavailable

standardize

readability.Accurate

manufactured

of2,andstanding

fromCD

Cdand

measuringmay

orpurchased,

heig

htofolderchildren

TALC)b,

andUNICEFa

requiretwopeople

$10285

UNICEF:$350

Weight/height

Usedtodistinguish

TALCb,andUNICEFa

Accuracydepends

Needstwopeoplefor

TALC:$27.50,

Chart(Thinness

betw

eenstunting

ontheaccuracy

foraccuratemeasur-

UNICEF:NA

Measure)

and

acutemalnutrition.

ofheightandw

eight

ing.Subjecttotearing.

Colo

r-codedtoidentify

measurestaken

Goodreadabilityand

nutr

itionalstatus

fromothersources

portability

(Scale,board)

HeightMeasuring

Mea

suresheightof

UNICEF

a

Accurate,and

Needstobemounted

$NA

Instrument

childrenandadults

standardizable

onthewall,notport-

able,buteasytouse.

Measuresheightup

to2m

a.

UNICEFSupplyDivision,

UNIC

EFPlads,

Freeport;DK-2100,

Copenh

agen,

Denmark.

Tel:(45)35-27-35-27;fax(45)35-26-94-21;e-mail:supply@

unicef.org;

website:www.supply.unicef.dk;o

rcontactUNICEFfieldoffice:www.unicef.org/uwwide/fo.h

tm.

b.

TeachingAidsatLowCost(TALC),POBox49,

StAlbans,

HertsAL14

AX,

England;Tel:(44)01727-853869;fax:(44)01727-846852;website:www.talcuk.org.

Payments

fromoverseasmustbemadeby1)Internationalmoneyorder,National

GiroorUKpostalorder;2)SterlingchequedrawnonUKbank;3)EurochequemadeoutinSterling;

4)USdollarcheckdrawnonUSb

ankusingcorrectrateofexchange;o

r5)UNESCOcoupons.

c.

CMS(UK)WeighingEquipmen

tLtd.,

18CamdenHighStreet,LondonNWIOJH,

U.K.;

Tel:(44)01387-2060or(44)0207383-7030.

d.

CenterforHealthPromotionan

dEducationoftheCentersfoDisease

ControlandPrevention,

1600CliftonRd.,

NE,

Atlanta,

GA30333;website:w

ww.c

dc.gov.

(AdaptedfromGriffiths,

1985)

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10

circumference measures are provided in several other resource manuals:

UNICEF: Growth Monitoring, 1986; FAO Supplementary Feeding Pro-

grams, 1990; and I. Shorr, How to Weigh and Measure Children, 1986

and in Annex 2 of the WHO Expert Committee Report (1995) Physical

Status: The Use and Interpretation of Anthropometry.

Age (in months)

Age is often the most difficult measurement to obtain. The first step is to

examine reliable birth records if available for the child. If this source is

not available, it will be necessary to estimate birth date and age. It is

important to know the traditional calendar if age is to be imputed from

talking with the mother. An example of a local calendar is provided in

Figure 2-3. Using the triangulation method (asking information in several

Figure 2-1: Measuring Arm Circumferencewith a Tape Measure

Source: Savage-King & Burgess, 1993.

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1

different ways) to confirm the birth date/age of the child will improve the

accuracy of the measurement. For example, after estimating the age of achild with a local calendar compare dental eruption, height, and motor

development with a separately assessed child of similar age (Jelliffe and

Jelliffe, 1989).

International references

The current international reference, adopted by the World Health Organi-

zation, uses data from the US National Center for Health Statistics (NCHS)

Figure 2-2: Measuring Arm Circumferencewith a Shakir Strip

Midpoint between tip ofshoulder and elbow

Straight arm

Source: Savage-King & Burgess, 1993.

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Figure2-3:SeasonalCalendarofaCom

munityinThePhilip

pines

(FAO,

1993b)

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as a benchmark of growth in infants and children. The NCHS compiled

the weights and heights of thousands of healthy children with reference

data derived from several sources. Information on infants from birth to 36

months of age was collected between 196075 using a population of

middle-class, white, bottle-fed Americans. Data for children ages 218

years are from the Health Examinations Survey and the National Health

and Nutrition Examination Survey (NHANES), and are representative of all

socioeconomic, ethnic, and geographical groups.

There is continuing debate about the appropriateness of these refer-

ences for children in developing countries. The NCHS reference is com-

posed of several different sample populations and as a result, the curves

are disjointed at 24 months. The majority of the study population was

bottle/formula fed, reflecting inadequately, the growth patterns of

breastfed infants.3 In addition, measurements were taken at three rather

3. In 1995, the WHO Working Group on Infant Growth concluded that to adequatelyreflect growth patterns consistent with WHO feeding recommendations (i.e., exclusive

breastfeeding through 6 months, with continued breastfeeding combined with ad-

equate complementary foods through two years), new growth curves based on refer-

ence data from exclusively breastfed infants from a variety of countries/regions should

be developed. A consistent, distinct pattern of growth for infants breastfed for at least

12 months emerged from an analysis of multiple, geographically diverse growth studies

by the Working Group. Typically, breastfed infants grew as or more rapidly than the

NCHS-WHO reference for 2 to 3 months, but showed a relative deceleration, particu-

larly in weight, from 3 to 12 months. Mean head circumference on the other hand, was

above the NCHS-WHO median throughout the first year. In the studies that went

through the second year, there was a reversal of the trend, with weight-for-age, length-for-age, and weight-for-length returning toward the current NCHS-WHO reference

means between 12 and 24 months of age. In the absence of a revision of the current

reference growth curves, health workers can easily misdiagnose thriving breastfed

babies as growth faltering, and wrongly counsel mothers to introduce solids and

breastmilk substitutes unnecessarily early on. In many environments, the risk of mor-

bidity and mortality due to contaminated feeding utensils and foods is high (Dewey,

et al., 1995 and WHO Working Group on Infant Growth, 1995). The new growth curves

are anticipated in late 2004 or early 2005.

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14

than one month intervals, which is less than ideal for characterizing the

shape of the growth curve. However, various studies have shown that the

growth standards achieved by children under 5 years of age in the NCHS

reference population can be attained by children in developing countries

if they are given adequate food and a relatively clean environment.

Therefore, WHO has endorsed these as a universal reference. The devel-

opment of country-specific references is time consuming and costly, and

use of a global reference has the advantage of permitting cross-country

comparisons.

Low Birth Weight (LBW)

Inadequate fetal growth (often approximated by low birth weight) is a proxy

indicator of poor maternal nutritional status as well, as a predictor of risk for

neonatal, infant, and young child (through at least 4 years) morbidity and

mortality. There is some evidence that over the long term, growth-retarded

infants may experience permanent deficits in growth and cognitive devel-

opment. Determinants of LBW include inadequate maternal protein-energyconsumption, anemia, malaria, tuberculosis, and smoking.

The newborns weight (in grams) is generally taken immediately after

delivery or within the first 24 hours of life. Although weight at birth by

gestational age is the best measurement (to differentiate between infants

who are small because they are pre-term and full-term infants who are

underweight), gestational age is difficult and often impossible to assess

or obtain in developing country settings. Thus under most circumstances,

incidence of low birth weight (defined as birth weight < 2500 gms) isassessed and used as a proxy for small for gestational age (SGA).

Table 2-2 provides a summary of currently established cut-offs for LBW in

individual newborns and for signaling when LBW is a problem of public

health significance.

At the individuallevel, in order to reduce morbidity and mortality and

optimize long-term growth and performance, LBW can be used for

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Table 2-2: Recommended Cut-offs for Low Birth Weight

Estimate ofIndicator Individual Newborn Population Risk

Low Birth Weight (LBW)a

Birth weight < 2500gms Prevalence > 15%b

Small for GestationalAge (SGA) 10th percentile Prevalence > 20%

Chest Circumferencec < 29 cm Prevalence > 15%

a. The 1990 World Summit for Children set as an end-of-century goal the reduction in the incidence

of low birth weight to less than 10 percent. However in 2003, incidence was 14 percent (UNICEF).

b. Populations with LBW prevalence of >15% (approximately twice the level of high income settings)

are at risk of long-term adverse effects on childhood growth and performance.

c. Not yet established as an official indicator of fetal growth.

(WHO Expert Committee, 1995)

screening, diagnosis, risk referral, and surveillance purposes (WHO

Working Group on Infant Growth, 1995). At the populationlevel, LBW

information is used to generate population estimates of the public healthsignificance of the problem, for targeting of interventions, to stimulate

public health action, and to monitor and evaluate health and develop-

ment progress. See Table 2-3 for global LBW prevalence rates.

Keep in mind that LBW data are prone to bias for several reasons. Birth

weights are generally collected in hospitals and clinics, introducing the

possibility of bias in areas with poor health care coverage and where the

majority of non-emergency births occur at home.

Weight-for-age (W/A)

Weight is influenced both by height and thinness. Low W/A (underweight)

is a combination indicator of height-for-age (H/A) and weight-for-height

(W/H). W/A is the most commonly reported anthropometric index and

used frequently for monitoring growth, identifying children at risk of

growth failure, and assessing the impact of intervention actions in growth

promotion programs. It is as sensitive an indicator as H/A in children

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16 Table 2-3: Percentage Prevalence Babies Born withLow Birth Weight (< 2500 grams)

Percent Percent PercentRegion/ Prevalence Region/ Prevalence Region/ PrevalenceCountry LBW Country LBW Country LBW

AFRICA E.EUROPE and SOUTH ASIAAngola 12 CENTRAL ASIA Bangladesh 30Botswana 10 Albania 3 India 30Burkina Faso 19 Armenia 7 Maldives 22C.A.R. 14 Azerbaijan 11 Pakistan 19Cameroon 11 Belgium 8 Sri Lanka 22Cape Verde 13 Bulgaria 10Comoros 25 Croatia 6 MIDDLE EAST andCongo, Dem. Rep. 12 Czech Republic 7 NORTH AFRICACte dIvoire 17 Hungary 9 Algeria 7Eritrea 21 Kazakhastan 8 Bahrain 8Ethiopia 15 Kyrgyztan 7 Egypt 12Ghana 11 Romania 9 Iran 7Guinea 12 Russian Federation 6 Iraq 15Guinea-Bissau 22 Turkey 16 Jordan 10Kenya 11 Turkmenistan 6 Lebanon 6Lesotho 14 Morocco 11Madagascar 14 LATIN AMERICA Oman 8Malawi 16 and CARRIBEAN Saudi Arabia 11Mali 23 Antigua and Barbuda 8 Tunisia 7Mauritania 42 Argentina 7 Yemen 32Mauritius 13 Barbados 10Mozambique 14 Belize 6 EAST ASIANamibia 16 Bolivia 9 China 6Niger 17 Brazil 10 Fiji 10

Nigeria 12 Chile 5 Indonesia 10Rwanda 9 Columbia 9 Korea, Rep. of 4Senegal 18 Costa Rica 7 Malaysia 10Sudan 31 Cuba 6 Mongolia 8Swaziland 9 Dominica 10 Myanmar 15Tanzania 13 Dominican Rep. 14 Papua New Guinea 11Togo 15 Ecuador 16 Philippines 20Tunisia 7 El Salvador 13 Solomon Is. 13Uganda 12 Guatemala 13 Thailand 9Zambia 10 Guyana 12 Vietnam 9Zimbabwe 11 Haiti 21

Honduras 14 TOTALS

Jamaica 9 Sub-Saharan Africa 14Mexico 9 Middle East andNicaragua 13 North Africa 15Panama 10 South Asia 30Paraguay 9 Latin America andPeru 11 the Caribbean 10Suriname 13 East Asia and theTrinidad/Tobago 23 Pacific 8Uruguay 8 World 16Venezuela 7 Least Developed 18

(UNICEF, 2004)

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1

under three years, and it has the advantage of requiring only one rela-

tively simple physical measurement (i.e., weight). However, because it is

dependent upon accurate age data availability, rounding of age is the

frequent cause of substantial systematic bias (Gorstein, et al, 1994).

Different age groups also affect sensitivity of W/A. Among the three most

common indices (W/H, H/A, W/A)while none of them have highpredic-

tive capacitiesweight-for-age has the highest predictive ability for child-

hood mortality (Pelletier, 1991).

The assessment of early growth deficits in an individualchildoften

detected during monthly growth monitoring sessionsis equally if not

more important than identifying the already malnourished child. W/A (or

better, weight gaingaingaingaingainsee Box 2-2), can be used to identify children at

risk of becoming malnourished, and guide preventive measures such as

Box 2-2: Rate of Weight Gain

In addition to assessing growth patterns through charting serial

W/A measurements, Savage-King and Burgess (1993) suggest the

following indicators of inadequate rate of weight gain in children

< 24 months:

A child who has lost weight

06 month old is gaining less than .5 kg/month

612 month old has no weight gain for 2 months

1224 month old has no weight gain for 3 months, especially if a

weight is below the 3rd centile

Tool #4 discusses alternative definitions of adequate growth patterns

using a combination of minimum monthly weight gain for different

ages with other indicators of health and nutrition status.

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18

Table 2-4: Classification of Malnutrition by Prevalenceof Low Weight-for-Age

Prevalence of Underweight(% of children < 60 months,Degree of Malnutrition below 2 Z-scores)

Low < 10Medium 1019High 2029Very high 30

(WHO Expert Committee, 1995)

nutrition counseling and entry into short-term food supplementation pro-

grams. (See Promoting the Growth of Children: What Works[Tool #4] for a

complete discussion of growth promotion.)

At the populationlevel, W/A can be used to identify areas of highest

need for interventions and to assist in the allocation of resources among

communities or regions. Weight-for-age is also used to gauge response

to program interventions and to predict the health consequences of an-

thropometric deficits for populations (based on the predictive relationshipbetween W/A and childhood mortality). The younger the child, the better

the use of W/A as an indicator of nutritional status.

As described earlier, the international reference standard uses data from

the NCHS. To identify underweight, a childs actual weight is compared

with that of a reference child of the same sex at exactly the same age.

Annex B, Tables B-1ac contain the reference data for children 05 years.

See Annex A for a discussion of the presentation of W/A data as Z-scores.

Table 2-4 contains the proposed classification of malnutrition in a popula-

tion using prevalence of low W/A. The classification of severity of malnu-

trition is useful for targeting purposes, but is not based on functional

outcomes. Even low levels of underweight may be a cause for concern

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1

because only 2.3% of children in a well-nourished population would be

expected to have W/A < 2Z scores.

Height-forHeight-forHeight-forHeight-forHeight-for-age (H/A-age (H/A-age (H/A-age (H/A-age (H/A))))) is a measure of cumulative linear growth and is

often influenced by long-term food shortages, chronic and frequent

recurring illnesses, inadequate feeding practices, and poverty. This index

is used primarily with children under five years of age, with low H/A com-

monly not appearing before 3 months of age. Children who are short for

their age relative to a reference standard are classified as stunted. Theprevalence of stunting among children generally increases with age up to

2436 months and then remains relatively constant thereafter.

For individualchildren, H/A is not used to monitorgrowth because of

errors in measurement of relatively small changes in the short-term. In

regions where there is a known high prevalence of stunting such as

South Asia, H/A can be used to screen individual children under two

years of age for intervention. In areas with low prevalence of low H/A,

short children are more likely to be genetically short, making it inappro-priate to assume a pathological basis for low H/A or to use the index as a

screening tool. (This can often be ascertained by looking at the height of

the childs parents.)

At the populationlevel the prevalence of stunting is useful for long-term

planning and policy development, for targeting a range of interventions

to a community(s), and for monitoring malnutrition at the community,

regional, or national level. H/A is frequently used as a reflection of socio-

economic status and equity. For example, height measurements of simi-lar age groups at intervals of years can demonstrate positive or negative

secular change within a community, region, or country. Poverty analyses

often use stunting as a nutritional indicator since it is cumulative and

cannot be compensated by fatness.

To identify whether a child is stunted, his/her actual height is compared

with that of a reference child of the same sex at exactly the same age.

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20

Table 2-5: Classification of Malnutrition by Prevalenceof Low Height-for-Age

Prevalence of Stunting(% of children < 60 months,Degree of Malnutrition below 2 Z-scores)

Low < 20Medium 2029High 3039Very high 40

(WHO Expert Committee, 1995)

Annex B, Tables B-2ae contain the NCHS reference tables for H/A for

children ages 060 months. Stunting data are presented as Z-scores,

comparing a child or group of children with a reference population to

determine relative status. See Annex A for a full discussion of Z-scores.

To assess or estimate the prevalence of malnutrition in a population,

results are presented as the prevalence of children who fall below the

standard cut-off. Table 2-5 contains the proposed classification of malnu-

trition in a population using prevalence of stunting. The classification ofseverity of malnutrition is useful for targeting purposes, but is not based

on functional outcomes. Interpret low and medium with cautiononly

2.3% of children in well-nourished populations would be expected to fall

below 2Z-scores, making even low levels of stunting cause for con-

cern. All cut-offs are merely indicators of risk, not necessarily of actual

malnutrition.

WWWWWeight-foreight-foreight-foreight-foreight-for-height (W/H)-height (W/H)-height (W/H)-height (W/H)-height (W/H)measures body weight relative to height. Be-

cause weight can fluctuate rapidly in children due to illness or inad-equate food intake, W/H reflects the currentnutritional status of a child,

with low W/H (wasting) indicating current acute malnutrition with failure to

gain weight or actual weight loss. However, low W/H can also be a result

of a chronic condition in some communities. Weight in individual children

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and population groups may exhibit marked seasonal patterns associated

with changes in food availability or disease prevalence. In non-emer-

gency situations, the highest prevalence of wasting generally occurs in

young children 1224 months of age.

Among individualchildren, W/H is a useful index for assessing nutrition

status under famine conditions and for identifying short-term nutrition

problems in non-emergency situations. Wasting is the usual indicator of

choice for targeting treatment of diarrheal and other diseases. High W/H(> +2 Z-scores) is used to screen children at risk for developing obesity

and future related morbidity such as heart disease. Given that a childs

weight should be more or less the same for a given height regardless of

age, W/H has the advantage of not requiring knowledge of childrens

ages (Gibson, 1990).

At the populationlevel under non-emergency conditions, W/H is usually

relatively constant at less than 5% with the exception of the Indian sub-

continent where prevalence rates are substantially higher (e.g., inBangladesh). W/H is used for determining seasonal stresses and allocat-

ing resources to vulnerable areas and population groups. In the case of

disasters, the W/H index can help to determine the severity of the emer-

gency, and the need for relief food rations. At the opposite extreme, W/H

is used to identify priority areas for interventions to reduce rates of over-

weight and obesity.

As described earlier, the international reference standard uses data from

the NCHS. To identify whether a child is wasted or overweight, a childsactual weight is compared with that of a reference child of the same sex

at exactly the same height. Annex B, Tables B-3ae contain the NCHS

reference tables for weight-for-length and weight-for-height. See Annex A

for a discussion of the presentation of W/H data as Z-scores.

Table 2-6 contains the proposed classification of malnutrition in a popula-

tion using prevalence of wasting. As is the case with height-for-age and

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Table 2-6: Classification of Malnutrition by Prevalenceof Low Weight-for-Height

Prevalence of Wasting(% of children < 60 months,

Degree of Malnutrition below 2 Z-scores)

Low < 5Medium 59High 1014

Very high 15

(WHO Expert Committee, 1995)

weight-for-age, the classification of severity of malnutrition is useful for

targeting purposes, but is not based on functional outcomes. Because

only 2.3% of children in well-nourished populations would be expected to

fall below 2Z-scores, even low levels of wasting may be cause for

concern. See sections on overweight under Body Mass Index (see page

26) and Adolescent Anthropometry (see page 34) for further discussionof cut-offs and population-based prevalence rates.

Mid-Upper ArMid-Upper ArMid-Upper ArMid-Upper ArMid-Upper Arm Cirm Cirm Cirm Cirm Circumfercumfercumfercumfercumference (MUAC)ence (MUAC)ence (MUAC)ence (MUAC)ence (MUAC), the measure of the diameter of

fat, bone, and muscle tissue of the upper arm, is an alternative index to

consider in situations where it is difficult to collect weight and height

measurements. For example, in settings where health workers are illiter-

ate or under emergency conditions, when screening is more important

than counseling, MUAC is useful. MUAC offers the operational advan-

tages of a simple, easily portable measurement device (the arm band/tape) and the use of a single cut-off for children under five years of age

(12.5 or 13.0 cm) as a proxy for low W/H or wasting. MUAC has also

been used as a screening device for pregnant women; because MUAC

is generally a stable measure throughout pregnancy, it is used as a proxy

of prepregnancy weight, and therefore an indicator of risk for low birth

weight babies. One type of color-coded measuring tape, the Shakirstrip,

is made from locally available materials and is appropriate for illiterate/

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innumerate workers; red signifies severe malnutrition, yellow is moderate

malnutrition, and green signals adequate nutrition. (See discussion on

p.7 for more information on measuring tools.)

Disadvantages of the index are the large variability in MUAC measure-

ments (a 0.5 cm error in MUAC has greater implications than a 0.5 cm

error in height) and the increased time/effort necessary for training and

standardization of MUAC measurements. Comparisons of MUAC with a

fixed cut-off and low W/H derived from the same population have demon-strated poor correlation of the two indicators when used for determining

individual nutrition status. More children were identified as malnourished

by MUAC (false positives), with the attendant implications for diminished

cost-effectiveness of an intervention program. However, at the community

level, MUAC has been found to be a superior predictor of mortality risk,

and thus could serve as an effective screening tool (WHO Expert Com-

mittee, 1995).

At the individuallevel, MUAC-for-age is recommended for screeningpurposes to identify infants/children and pregnant women who need supple-

mentary food or therapeutic feeding, and possibly treatment for disease.

It is not recommended for assessing response to interventions (WHO

Expert Committee, 1995).

At the populationlevel, MUAC-for-age or MUAC is useful for targeting

purposes (WHO Expert Committee, 1995) including determining the se-

verity of a disaster or emergency situation, the need for/type of relief

rations, and priorities for allocation of resources. Because of the highcorrelation between low MUAC and mortality in under-fives, this index is

potentially useful for predicting the consequences of malnutrition identi-

fied by anthropometric deficits in populations.

WHO Expert Committee (1995) proposed that MUAC with a fixed cut-off

be used as an additional screening tool in non-emergency situations (but

not as a substitute for weight- and height-based indices), and suggests

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Table 2-7: Classification of MUAC in Children 1260

MonthsClassification Cut-Off Value

Normal > 13.5 cmModerate wasting 12.513.5 cmSevere wasting < 12.5 cm

(FAO, 1993a)

that MUAC-for-age is an acceptable substitute for W/H in the context of

population-level nutritional surveillance. The reference data for MUAC-

for-age are based on US children aged 6 to 60 months from the National

Health and Nutrition Examination Surveys (NHANES). Annex B, Tables

B-4ac contain reference tables for MUAC measurements (median and

standard deviations) for boys and girls ages 660 months.

Table 2-7 contains the cut-offs and classifications recommended for

MUAC in children ages 1 to 5 years. Cut-offs for pregnant women aredetermined on the basis of local reference data; measurements between

2123.5 cm have been used in the past to determine risk of LBW infants.

Height-for-Age in School Children

Used solely for population-level analysis, this index captures the earlier

health and nutrition histories as well as the broader socioeconomic and

environmental factors affecting school-age children four to six years after

the fact. A height census is the measurement of height of all entering firstgraders at schools throughout a country. Experience in Latin America

(PAHO/WHO/UNICEF, 1997) suggests that the results from a height-for-

age census can be used to advocate for allocation of social programs, to

identify particularly needy geographic areas, and to plan and target pov-

erty alleviation and other types of social welfare programs. Height-for-age

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in school children is not the most appropriate indicator to target indi-

vidual or population level nutrition intervention strategies, but rather to

advocate for increased resources to the education sector. It is useful for

targeting school-based interventions designed to increase enrollment,

promote attendance, and prevent dropouts (PAHO/WHO/UNICEF, 1997).

As with most anthropometric indicators, it is important to use the school

height census findings as part of a more complete set of data about the

physical, economic, and sociocultural context of a community or region.Height-for-age data will not answer questions about the determinants of

earlier poor health and nutrition conditions. The primary objective of

height censuses is the construction of a classification scale and not ex-

act prevalence estimates of height retardation in a specific population

(PAHO/WHO/UNICEF, 1997).

A school census provides relatively easy access to a population, and

may well furnish greater coverageparticularly at first gradethan sur-

veying health center clients. It can be implemented in a few months andis relatively cheap. The technology for obtaining the measurements is

simple and inexpensive, and teachers can readily be trained to carry out

the survey. The first grade of school is often the point at which the great-

est numbers of individuals of similar age from different socioeconomic

backgrounds in the country are brought together, allowing for inter-

regional comparisons to be made.

It is important that age data are collected rather than making the as-

sumption that all first year students are the same age. And whileschool-based data may capture high percentages of the school-age

population in middle-income countries, the most common source of

bias in height-for-age surveys is population coverage. Problems are

related either to the exclusion of a large number of schools from the

sampling frame because of accessibility issues, or a high percentage

of children missing from school enrollments because of gender bias,

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health status, household poverty and so forth. Typically, the lack of

coveragegenerally in economically disadvantaged areasresults in

underestimation of stunting prevalence and the distortion of regional

classification/prioritization systems.

Information on height is usually collected at the level of the individual

school. Data are presented as mean Z-scores and estimates of preva-

lence of low height-for-age, stratified by sex and by age group. Ideally,

local school prevalence estimates will be aggregated to correlate with acountrys political or administrative units; the small sample sizes provided

by the individual schools have the problem of large standard errors.

The Family Assistance Program/Women Head of Household Food Coupon

Program (PRAF) in Honduras used an annual nationwide school nutrition

census of all 6 to 9 year-old students entering the first grade of public

schools to improve targeting of the food coupon distribution system.

Recommended references for height-for-age values for school-age chil-dren are the NCHS/WHO data in Annex B Tables B-5ab. For a more

detailed discussion of the height-for-age census, refer to the joint techni-

cal report by PAHO/WHO/UNICEF (1997).

Body Mass Index (BMI)

BMI is defined as: (weight in kilograms)/(height in meters2). For adults in

developing countries, anthropometry has largely been used to identify

chronic energy deficiency (thinness) and at the opposite extreme, toclassify problems of obesity. BMI is highly correlated with fat mass and is

therefore a reasonably good index of body energy stores as fat. As an

index of nutritional status, BMI accounts for the fact that weight is influ-

enced by height and is therefore less biased by this association than

other indices.

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Chronic energy deficiency

According to WHO Expert Committee (1995), at the individuallevel, one-

time measurement of weight or BMI in men and non-pregnant women is

of limited use for predicting health risks or benefits from nutrition or

health interventions. The degree of unintentional weight loss of an adult

is a better predictor of individual morbidity and mortality risk related to

low weight or thinness. Nonetheless, the WHO Expert Committee (1995)

has published BMI tables (Annex B Table B-6) and established cut-offsfor use in determining degrees of chronic energy deficiency in individu-

als (see Table 2-8 ). With pregnant women, pre-pregnancy or first tri-

mester BMI can be used to screen for food supplementation, and to

identify women at risk for delivery of a low birth weight or preterm infant

(see page 31 for more information).

At the populationlevel, monitoring adult nutritional status with BMI in non-

emergency situations can be a useful tool for assessing nutritional or

other socioeconomic deprivation. Low BMI data can be used as thebasis for targeting services to a community; a changing BMI profile may

be indicative of a population undergoing adverse social or economic

change.

Table 2-8: Proposed BMI Cut-Offs for Chronic EnergyDeficiency in an Individual Adult

BMI Range Diagnosis

Chronic Energy Deficiency< 16 Grade 3 thinness (severe)1616.9 Grade 2 thinness (moderate)1718.4 Grade 1 thinness (mild)18.524.9 Normal

(WHO Expert Committee, 1995)

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Table 2-9: Adult Thinness as a Public Health Problem

Population prevalence BMI < 18.5 Classification

59% Low prevalence: warning sign,monitoring required

1019% Medium prevalence: poor situation2039% High prevalence: serious situation> 40% Very high prevalence: critical

situation

(WHO Expert Committee, 1995)

BMI is also a general indicator of adult health status, particularly low

BMI. Establishing a baseline picture of the BMI distribution for a popula-

tion enables detection of threats to food security and the need for rapid

intervention in an area undergoing either man-made or natural disaster

emergency conditions. In an emergency feeding program, anthropo-

metric monitoring of adults helps to discriminate between problems ofadequate supplementary food supplies and other public health inter-

ventions because adults are less susceptible to epidemic infection

than malnourished children. Adult BMI data are presumed to more

directly reflect dietary adequacy rather than a complicated interplay

of infection, appetite, feeding behaviors, and other factors that affect

child nutrition status.

Table 2-8 contains the recommended cut-offs defining varying degrees of

thinness in an individual, and Table 2-9 suggests prevalence levels signi-fying a public health problem within a population.

Overweight

Overweight (excess energy stored as fat resulting from energy intake

exceeding expenditure) is associated with increased risk of morbidity

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(e.g., coronary heart disease, diabetes mellitus, gallbladder disease,

some cancers, and musculoskeletal disorders) in most populations.

BMI is used to classify individualsin terms of overweight, with further

testing necessary to identify individual risk factors (e.g., smoking, dietary

and exercise habits, blood pressure, serum lipids, family history, etc.) for

specific types of disease. According to the World Health Report(WHO,

2002), noncommunicable diseases accounted for almost 60% of the

worlds 56 million deaths in 2001. Five of the six main risk factors areclosely related to diet and physical activity.

At the populationlevel, overweight is a sensitive indicator of energy

imbalance caused by a combination of excessive energy intake and

insufficient energy expenditure. Because it is such a difficult condition

to treat, usually begins in childhood, and is already a widespread prob-

lem in industrialized countries, interventions need to focus on preven-

tion. Establishing needs and priorities for intervention programs is

achieved through representative population surveys, with a prevalenceof BMI> 30 (or > 85 percentile) suggested as the principal indicator

(WHOTechnical Report Series No. 916, 2003).

Age-specific and age-standardized proportions of the population above

a certain BMI cut-off can also be used to evaluate health promotion and

disease prevention programs in which weight control is one goal. To

evaluate interventions for prevention of overweight in populations where

prevalence of obesity is low, monitor longitudinal weight development.

Efficacy of the intervention can be judged with a case-control studydesign and a follow-up period of at least five years.

Anthropometric data are less useful for targeting specific interventions

because of the interplay of genetics with obesity. Genetic differences

between populations influence the degree of risk associated with over-

weight as well as the types of disease that may occur as a result of

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30

excess body weight. For example, it appears that abdominal fatness may

be less of a risk for cardiovascular disease and diabetes in black women

than in white, while Asians and Mexican-Americans appeared to have

higher risks of developing non-insulin-dependent diabetes mellitus than

Caucasians of similar BMI (WHO Expert Committee, 1995).

Table 2-10 contains the recommended cut-offs defining varying degrees

of overweight in an individual.

Anthropometry During Pregnancy

Anthropometric evaluation of pregnant women has the advantage of

being a fairly widely used, low-technology procedure which generates

information about the nutritional status of the mother and growth of the

fetus (WHO Expert Committee, 1995).

Useful application of anthropometric data from pregnant women de-

pends on the availability of resources and the likelihood of interveningto avert negative pregnancy outcomes. For instance, when limited

resources (i.e., no scales) make weight data collection impossible, short

height or mid-upper arm circumference may be used as a screening tool.

There may be over-classification of at-risk women. Setting cut-offs will

similarly depend on availability of local resources for intervention.

Table 2-10: Classification of Overweight in Adults by BMI

BMI Range (kg/m2) Classification

2529.9 Overweight (pre-obese)3034.9 Class I obese3539.9 Class II obese40 and above Class III obese (extreme obesity)

(National Institutes of Health, 2004)

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The preferred indicators of pregnancy outcome are pre-pregnancy

weight, body mass index (BMI) through the first 20 weeks of gestation,

weight gain during pregnancy, or height. These indicators provide some

assessment of risk for the woman during delivery and of potential health

problems for the newborn child. The WHO Collaborative Study on Mater-

nal Anthropometry and Pregnancy Outcomes (1995) found that anthro-

pometric indicators are more strongly related to fetal growth than to

complications of labor and delivery, although stature can be a relatively

strong predictor of delivery complications and maternal mortality.

For all of these indicators, selection of one or a combination of several

will depend upon what is being assessed: maternal and/or infant risk of

poor health/nutrition outcomes, selection of one or more interventions, or

response to an intervention(s). And critically, the choice of cut-off for a

particular indicator rather than the indicator itself, may be the issue of

most importance for determining the optimal use of maternal anthropom-

etry. For example, the cut-off for BMI best suited to predict risk for intrau-

terine growth retardation (IUGR) might well be lower than the BMI cut-offthat best indicates response to an intervention. The nature of the out-

come (e.g., LBW, prematurity), the nature of the intervention (e.g., food or

iron supplementation, reduced workload, child-spacing), the distribution

of the anthropometric measurement in the population (e.g., percentage of

the population below various cut-offs), the prevalence of the outcome,

and the importance of the cause targeted for intervention relative to other

causes, will influence the selection of indicator and cut-offs.

Pre-pregnancy weight

Weight prior to pregnancy or within the first 20 weeks of pregnancy is a

measurement frequently used to indicate the need for maternal weight

gain during pregnancy and to target women for supplementary feeding.

It is currently the most useful screening indicator for risk of low birth

weight (due to IUGR) in infants. Weight assessment after 20 weeks

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32

gestation is used for referring women to facilities where small for gesta-

tional age (SGA) and preterm infants can receive specialized care. Popu-

lation-specific cut-offs for pre-pregnancy weight should be established

within the range of 4053 kg.

Body Mass Index (BMI)

The WHO Expert Committee recommends the use of BMI with pregnant

women for prevention of preterm delivery or referral for neonatal care inpopulations at risk of preterm delivery. Measured during the first trimester,

a population-specific cut-off between 17 and 21 has moderate sensitivity

and specificity for predictive purposes.

Low BMI (population-specific cut-offs) has also been used to determine

which women should receive counseling on diet and/or supplementary

feeding. It is important to note that there are several assumptions con-

cerning causality of low BMI and the efficacy of the feeding intervention

implicit in this choice of targeting indicator:

1) Low maternal BMI is caused by chronically low energy intake and not

by morbidity;

2) Low intake is caused by inadequate access to food at the household

level, and not by detrimental intrahousehold allocation patterns; and

3) Supplementary food will be preferentially available to pregnant and/or

lactating women and will not substitute for the home diet (WHO Expert

Committee, 1995).

Height/Stature

Height in adults is a combination of genetic potential for growth and envi-

ronmental effects that influence growth. Specifically for pregnancy, it is

an estimate of pelvis size and the only anthropometric measure that

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serves (with moderate accuracy) as a predictor of need for an assisted

delivery. In several studies short maternal height has been associated

with poor growth of the fetus (intrauterine growth retardation or IUGR)

and subsequently, low birth weight. Current recommendations suggest

setting population-specific cut-offs between 140150 cm; height less

than 145 cm is a cut-off associated with increased risk of maternal mor-

tality (Krasovec and Anderson, 1991). Height should not be used to tar-

get a narrow intervention such as supplementary feeding because it

does not reflect current nutrition status, nor will it capture maternal re-sponse to feeding in most cases. Height is probably best employed as a

screening instrument in situations of limited resources, bearing in mind

that considerable misclassification of cases will result.

Weight gain during pregnancy

Although this indicator is most reflective of the pregnancy period (gener-

ally 20+ weeks), its findings come at a point when intervention options for

the mother or fetus are limited. It is useful for referral for specialized laborand delivery and neonatal care, and for selecting individuals for interven-

tion during lactation. Changes during pregnancy are relative to height

and to initial nutritional status; therefore some clinicians suggest that the

percentage weight gain relative to pre-pregnancy weight be used (set-

ting a 1525 percent increase as desirable) versus an absolute gain of

10 kg over the course of the pregnancy. Another weight gain cut-off used

frequently is 1 kg/month over the last two trimesters.

Mid-upper arm circumference (MUAC)may also be considered for screen-ing (not monitoring) purposes as a predictor of low birth weight, particularly

in cases where program resources limit equipment options and/or women

have only one or very few contacts with the healthcare system during their

pregnancy. Because MUAC increases only minimally if at all during preg-

nancy, it is used as a proxy for maternal pre-pregnancy and early preg-

nancy weight. The disadvantages of MUAC are the possibility for

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34

Box 2-3: Possible Determinantsof Poor Growth during Pregnancy

Some of the pertinent issues to look at include:

Availability and access to key foods

Cultural perceptions of appropriate diet during pregnancy

Estimates of physical work/energy expenditure

Prevalence and type of maternal infections

(WHO Expert Committee, 1995 )

measurement error, the greater impact of that error for misclassification in

comparison to other measurements such as weight, and the increased

effort necessary for training and standardization of MUAC measurements.

Population-specific cut-offs will need to be determined based on local

reference data and availability of resources for intervention. MUAC cut-offs

between 2123.5 cm have been used for identification of women likely to

have LBW infants (Krasovec and Anderson, 1991).

Identification of individuals or population groups at risk for poor preg-nancy outcomes is only the first step. An assessment of possible determi-

nants (see Box 2-3) will help to understand the cause of poor maternal

weight gain and/or problematic fetal growth during pregnancy as well as

direct efforts at intervention.

Adolescent Anthropometry (children 1019 years of age)

Use of anthropometry for diagnostic and screening purposes in adoles-

cents is constrained primarily by the difficulty of capturing the subjects.

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And while it is a critical time for the development of many health and

nutrition risks (e.g., obesity, short stature in girls), it is a pointless exercise

unless specially-targeted intervention strategies (nutrition, life skills

education, family planning, and STDs/AIDS) prevention will be planned

and implemented.

It is important to disaggregate adolescent anthropometric data by sex

because of the differences in size and timing of the growth spurt between

the sexes. Due to the transient nature of adolescent growth patterns andwide variability in timing of maturational changes, age intervals for col-

lecting data should be shortened to six months (as opposed to one-year

intervals during middle childhood), for the period two years after the

growth spurt until adult height is attained.

Height-for-age (H/A), body mass index (BMI), and BMI-for-age are the

most commonly constructed indices for this population group. Weight-for

height (W/H) is no longer useful because the relationship between weight

and height changes with age and maturational stage during adolescence.BMI-for-age is recommended as the best indicator during adolescence,

incorporating information on age, providing continuity with adult indicators,

and applicable to both underweight and overweight conditions.

Provisional references for adolescent anthropometry use NCHS data,

which include standard deviations and percentiles of height and weight

through the adolescent years. While BMI-for-age percentiles are acknowl-

edged to be skewed toward higher values, they are currently recom-

mended as the best option for uniform reporting purposes until other dataare compiled. H/A and BMI-for-age percentiles are presented in Annex B,

Tables B-7ab.

For individuals, stunting (H/A < 2 Z-scores) is used to identify adoles-

cents who could benefit from improved nutrition or treatment of other

underlying health problems, with the greatest impact expected for

premenarcheal girls and pre- or early pubertal boys. Particularly for girls,

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stunting is related to poor reproductive outcomes (low birth weight,

cephalopelvic disproportion,5 dystocia,6 and increased risk of cesarean

section and possible postmenopausal osteoporosis). Menarche in girls

and the attainment of an adult voice in boys indicates that peak stature

velocity has already occurred, and the effect of nutrition interventions on

stunting will be minimal.

Thinness (low BMI-for-age) in adolescents is useful for determining need

for supplementary feeding, nutrition education, and referral to medicalcare, with a suggested cut-off of BMI-for-age < 5th percentile.

Adolescents with BMI 85 percentile are at risk of overweight. Generally,

in populations where there are large numbers of overweight individuals, it

is recommended that adolescents with high BMI have additional screen-

ing to identify obesity-related risk factors such as high blood pressure,

family history of cardiovascular disease or diabetes mellitus.

Use of adolescent anthropometry at the populationlevel is similar to thatfor individuals. It is helpful to determine median ages for maturational

indicators (menarche, breast and genitalia development, attainment of

adult voice) for a population in order to facilitate cross comparison with

other populations after adjusting for maturational age (WHO Expert Com-

mittee, 1995).

Summary statistics for thinness should be reported for targeting pur-

poses (mean, SD) by age and sex groups, as well as the frequency

below the 5th percentile of BMI-for-age. Identifying regions with a highproportion of thin adolescents will help to guide decisions about design

of intervention programs and the allocation of resources. Premenarcheal

5. Cephalopelvic disproportion is a condition in which the maternal pelvis is too small

for the size of the fetal head.

6. Dystocia denotes a difficult labor due to fetal or maternal causes.

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3

girls and pre-pubescent boys are the at-risk groups that will derive the

greatest benefit from intervention.

To assess response to interventions directed at excess thinness among

adolescents, evaluate frequencies of BMI relative to either the NCHS

reference data or local reference standards. Secular change in thinness

prevalence can be a useful indicator of overall social or economic im-

provement (or decline). It is recommended that surveillance of adoles-

cents (usually a component of surveillance covering other populationgroups as well) occur every five years during periods of socioeconomic

change or while programs are in progress. During periods of social up-

heaval or rapid positive (or negative) change, more frequent assessment

is optimal. Ten-year intervals are sufficient otherwise (WHO Expert Com-

mittee, 1995). Again, report mean and SD of BMI and frequencies of BMI-

for-age < 5th percentile.

In areas where overweight is an identified problem, prevalence can be

estimated by an anthropometric survey. Survey results will also assist withthe design or modification of intervention programs. Based on BMI refer-

ence data (Annex B Table B-6), report frequencies of adolescents with

BMI 85 percentile, mean, median, and SD of BMI and frequency of

BMI 30, disaggregated by age and sex.

To determine obesity (excessive body fat), the WHO Expert Committee

recommends combined use of three indices: BMI-for-age, triceps and

sub scapular skinfold thicknesses (TRSKF and SSKF). BMI alone is an

inexact measure of total body fat and obesity (implying knowledge ofbody composition) is limited to those adolescents both at risk of over-

weight (high BMI) and characterized by high levels of subcutaneous fat

(high TRSKF- and SSKF-for-age). The suggested cut-off values in Table

2-11 are provisional, and are based on limited evidence of universal ap-

plicability. See Tables B-8a to B-8b and B-9a to B-9b in Annex B for refer-

ence percentiles of triceps and sub-scapular skinfold thicknesses for

adolescents.

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Table 2-11: Proposed Cut-Off Values for AdolescentAnthropometry

Indicator Indices Cut-Off Value

Stunting/low H/A H/A < 2 Z-score; 3rd percentileThinness or low BMI for age BMI for age < 5th percentileAt risk of overweight BMI for age 85th percentileObese (simultaneous use BMI for age 85th percentile and

of all three indicators TRSKF for age 90 percentile and

is recommended) SSKF for age 90th percentile

(WHO Expert Committee, 1995)