ANTHROPOMETRY

Anthropometry: Introduction

Anthropos- "man" andMetron"measurementA branch of anthropology that involves the quantitative measurement of the human body.

Gold standard of nutritional assessment. It is the single most portable, universally applicable, inexpensive and non-invasive technique for assessing the size, proportions and composition of the human body.

It is used to evaluate both under & over nutrition.The measured values reflects the current nutritional status & dont differentiate between acute & chronic changes*

EQUIPMENTS REQUIRED

STANDARD GROWTH CHARTS AND TABLES: The growth chart developed by the NCHS (National Centre for Health Statistics) from US population is the currently accepted WHO standard of growth pattern from birth to 20 years.

Weighing machines:Electronic weighing scales are preferred.Beam type weighing scale (Detecto scale) is also acceptable.

Infantometer for length measurement.Anthropometer or stadiometer for height measurement.

Nonstretchable but flexible plastic tape. Harpenden skin fold calliper.

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Parameters of anthropometryAge dependent factors:- Weight Height Head circumference Chest circumference

Age independent factors:-Mid-arm circumference (1-5 years) Weight for height Skinfold thickness Mid upper arm/height ratio

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Weight The measurement of weight is most reliable criteria of assessment of health and nutritional status of children.

The weight can be recorded using a : Beam type weighing balance Electronic weighing scales for infants and children Bathroom type of mechanical scale (very unreliable) Salter spring machine (in field conditions)

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METHOD OF RECORDING BODY WEIGHTSet the weighing scale on a flat horizontal surface and correct the zero error before recording the weight. Always remove the shoes, and clothing should be the minimum, but hypothermia should be avoided.

Child should not be in contact with any other object. Weight can be read directly or by balancing the beam depending on the type of weighing machine. Record the reading when the beam is steady at its balance point or the pointer becomes stable. ,

In field conditions Salter spring machine is quite satisfactory because it is convenient to carry. The balance is hung from a hook or held by an attendant and baby is placed on the sling attached to the bottom hook.

The average birth weight of a normal Indian newly born baby after 40 weeks of gestation is 2.8 kg. WHO accepted standard is 3.5 kg. Increments in weight gain ideally should be compared with growth chart or table. Weight Increments

The periodic recording of weight on a growth chart is essential for monitoring the growth of under-five children.

Growth Velocity :

1,2,3 months 1.0kg/month(30g/day) 4,5,6 months 0.75kg/month(20gm/day) 7,8,9 months 0.50kg/month(15g/day) 10,11,12 months 12g/day 1-3 years 2.25kg/yr 4-9 years 2.75 kg/yr 10-18 years 5.0-6.0kg/yr (0.5kg/month)

B. Weight at 4-5 months 2 x birth weight Weight at 1 year 3 x birth weight Weight at 2 years 4 x birth weight Weight at 7 years 7 x birth weight

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WEECHS FORMULA3 12 months Expected weight(kg) = age (months) + 9 / 21- 6 years Expected weight(kg) = age (years) x 2 + 87 12 years Expected weight(kg) = age (years) x 7 - 5 / 2*

Classification of Malnutrition by Indian Academy of Pediatrics*

Weight for age *Grade of malnutrition>80 %71-80%61-70%51-60%

Length or Height/Stature Measurement TechniqueUpto 2 years of age Recumbent Length is measured with the help of an Infantometer .

In older children Standing Height or Stature is recorded. It is convenient to use an Inbuilt Stadiometer affixed on the wall which provides a direct read out of height with an accuracy of +/- 0.1cm.

Nutritional deprivation over a period of time affects the stature or linear growth of the child .

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Technique of length measurement The infant is placed supine on the infantometer.

Assistant or mother is asked to keep the vertex or top of the head snugly touching the fixed vertically plank.

The leg are fully extended by pressing over the knee, and feet are kept vertical at 90 , the movable pedal plank of infantometer is snuggly apposed against soles and length is read from scale. *

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Technique for height measurementIn older children who can stand , height can be measured by the rod attached to the lever type machine or by stadiometer.

Child should stand with bare feet on the flat floor against a wall with fit parallel and with heels buttocks, shoulders and occiput touching the wall. Head should be kept in Frankfurt plane.

With the help of a wooden spatula or plastic ruler. The topmost point of the vertex is identified on the wall.*

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Height Velocity

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At birth 50cms Gain during 1st year 25cms Gain during 2nd year 12.5cmsGain during 3rd year 7.5 to 10cmsGain during 3 12 years 5 to 7.5cmsAdolescence 8cms/yr for girls during 12 to 16 years 10cms/yr for boys during 14 to 18 years

Birth to 3 months 3.5cm/month 3 6 months 2.0cm/month 6 9 months 1.5cm/month 9 12 months 1.3cm/month 2 5 years 6 8cm/year 5 12 years 5cm/year

AGE Approximate rate of increase in stature

B] Expected height upto 12 yrs.

length or height (in cms) = age in years x 6 +77 ( Weechs formula )

C] ] Prediction of adult height

Parental height , Tanners formula and Weechs formula are used.

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HEAD CIRCUMFERENCE

Brain growth takes place 70% during fetal life, 15% during infancy and remaining 10% during pre-school years.

Head circumference are routinely recorded until 5 years of age.

If scalp edema or cranial moulding is present , measurement of scalp edema may be inaccurate until fourth or fifth day of life .

The head circumference is measured by placing the tape over the occipital protuberance at the back and just over the supraorbital ridge and the glabella in front.

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The marasmic children are seen to have relatively large head for their body size because brain growth is minimally affected by malnutrition.

During states of undernutrition of varying severity, weight, linear growth (height) & brain growth are affected in that order.

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Expected head circumference in children*

Age Head circumference (cm) At birth 34 35 2 months 38 3 months 40 4 months 41 6 months 42 - 43 1 year 45 - 46 2 years 47 - 48 5 years 50 - 51

Head Circumference Growth Velocity

During first year there is 12 cm increase in head circumference , while 1 5 year age , only 5 cm gain occur in head size.

Adult head size is achieved between 5 to 6 years .the following formula (Dines formula) is used for estimating the head circumference in the first year of life : - ( length in cm + 9.5 ) 2.59 2

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Till 3 months 2 cm/month 3 months 1 year 2cm/3 month 1 3 year 1cm/ 6 month 3 5 year 1cm/ year

The term Macrocephaly refers to OFC of more than 2SD above the mean while Microcephaly refers to OFC more than 3SD below the mean for age , sex , height and weight.*

Chest circumferenceIt is usually measured at the level of nipples, preferably in mid inspiration.Some workers recommend measurement of the chest circumference at the level of xiphisternal junction because the location of nipples may be variable. In children 5 years - standing position*

Relationship between head size with Chest Circumference:

At birth: head circumference > chest circumference by upto 3 cms.

At around 9 months to 1 year of age: head circumference = chest circumference,

but thereafter chest grows more rapidly compared to the brain.

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The head circumference is greater than chest circumference by more than 3 cms in : a) preterms b) small-for-date , & c) hydrocephalic infants

In malnourished children, chest size may be significantly smaller than head circumference because growth of brain is less affected by undernutrition. Therefore there will be considerable delay before chest circumference overtakes head circumference.

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In microcephaly chest exceeds the head in circumference earlier than 9 months and in hydrocephalus head continues to remain larger than chest even after 1 year of age.

Growth of chest is adversely affected in protein energy malnutrition, thoracic cage abnormalities, spinal muscular atrophy and congenital anomalies of lungs.

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AGE INDEPENDENT CRITERIA FOR ASSESSMENT OF NUTRITIONAL STATUSMid-upper arm circumferenceThickness of subcutaneous fatBody ratiosWeight for heightBody mass indexUpper segment/ lower segment ratioArm spanObesity *

MID-UPPER ARM CIRCUMFERENCEDuring 1-5 Yrs of age it remains reasonably static between 15-17cms among healthy children .

It is conventionally measured over the left upper arm , at a point marked midway between acromion (shoulder) and olecranon (elbow) with arm bent at right angle.

The child is asked to stand or sit with the arm hanging loose at the side.

MUAC is measured with a fiber glass or steel tape.

If it is less than 12.5 cm it is suggestive of severe malnutrition.If it is between 12.5 -13.5 cm it is indicative of moderate malnutrition.

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Bangle test quick assessment of arm circumference. A fiber glass ring of internal diameter of 4 cm is slipped up the arm, if it passes above the elbow, it suggests that upper arm is less than 12.5 cm and child is malnourished.

Shakir tape is a fiber-glass tape with red less than 12.5 cmyellow 12.5- 13.5 cm green greater than 13.5 cmshading so that paramedical workers can assess nutritional status without having to remember the normal limits of mid arm circumference.*

QUAC stick Quaker Upper Arm Circumference Stick

It is developed on the principle that acute starvation severely affects mid-arm circumference while height is unaffected.It is a height measuring rod, calibrated in MAC.Values of 80% MAC for Ht. are marked on stick at corresponding ht. levelsThe malnourished child would be taller than the anticipated height derived from the mid-arm circumference

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MAC (cm) Ht. (cm)16.5133.013.5103.512.570.0

Skinfold thicknessMeasured with Herpendens caliperTriceps or subscapular region

The skinfold with subcutaneous fat is picked up with thumb and index finger, and caliper is applied beyond the pinch.

Fat thickness>10mm - healthy children 1-6 years

Body ratiosRao & Singhs weight-height index:= [weight (kg) / (height)2 cms ] * 100 normal index is more than 0.15

Kanawati index: (during 3m to 4 years)= Mid-arm circumference / Head circumference*

Normal 0.331Mild 0.310 0.280Modreate 0.279 0.250Severe < 0.250

WEIGHT-FOR-HEIGHT Weight-for-height = Weight of the patient (kg) X 100 Weight of normal child of same height

WASTING

*Reference standard NCHS data *

Weight-for-Height *Wasting>90%80-90 %70-80 %

Classification When malnutrition has been chronic, the child is stunted, weight-for-age is low/normalheight-for-age is lowweight-for-height is normal.

In Acute malnutrition, the child is wasted,weight-for-age is lowheight-for age is normalweight-for-height is low*

BODY MASS INDEX (BMI)A BMI-for-age of > 85th percentile is suggestive of Overweight.

A BMI-for-age of > 95th percentile is or when it is associated with triceps or skinfold thickness-for-age of > 90th percentile, it is diagnostic of Obesity. *

Ponderal index : - it is another parameter which is similar to BMI and is used for defining newborn babies with intrauterine growth retardation. PI = (Body weight in grams) 100 length (cm) In malnourished small-for-date babies (asymmetric IUGR), ponderal index is

PROPORTIONAL TRUNK AND LIMB GROWTHThe mid-point of the body in newborn is at umbilicus whereas in an adult the mid-point shifts to the symphysis pubis due to greater growth of limbs than trunk.

The UPPER SEGMENT (vertex to upper edge of symphysis pubis) to LOWER SEGMENT (symphysis pubis to heels) ratio at birth is 1.7 to 1.0 .

This gradually becomes 1.0 to 1.1 in healthy adults.

In infants upper segment (crown to symphysis pubis) can be measured by using infantometer.

The lower segment is obtained by subtracting the upper segment from total length.

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Infantile upper segment to lower segment ratio (trunk abnormally large or limbs abnormally small) is seen in :

AchondroplasiaCretinismShort limbed dwarfismSexual precocityBowed legs

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Advanced upper segment to lower segment ratio (trunk abnormally short or limb abnormally long) is seen in:

ArachnodactylyHypogonadismEunuchoidismTurner SyndromeKlinefelters SyndromeChondrodystrophySpinal deformities (rickets, potts spine) *

ARM SPAN It is the distance between the tips of middle fingers of both arms outstretched at right angles to the body, measured across the back of the child.

In under-5 children , arm span is 1 to 2 cm smaller than body length.

During 10-12 years of age , arm span = height.

In adults arm span is more in adults by 2 cm.

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Abnormally large arm span is seen in patients with Arachnodactyly (Marfan syndrome)EunuchoidismKlinefelters SyndromeCoarctation of aorta

Arm span is short compared to height in patients with :Short limbed dwarfismCretinismAchondroplasia

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ADVANTAGES OF ANTHROPOMETRYLess expensive & need minimal training

Readings are reproducible.

Objective with high specificity & sensitivity

Measures many variables of nutritional significance (Ht, Wt, MAC, HC, skin fold thickness, waist & hip ratio & BMI).

Readings are numerical & gradable on standard growth charts

Limitations of AnthropometryInter-observers errors in measurement

Limited nutritional diagnosis

Problems with reference standards, i.e. local versus international standards.

Arbitrary statistical cut-off levels for what considered as abnormal values.

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Thank you

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*Monitoring the weight is helpful in diagnosing malnutrition at early stage**Used to calculate expected weight between the ages of 3 months and 12 years*Tragion- an anthropometric point situated in the notch just above the tragus of the ear.**