ANTHROPOMETRY

RVS Chaitanya koppala

Anthropometry: Introduction

•Anthropos - "man" and Metron "measurement”•A branch of anthropology that involves the quantitative measurement of the human body.

•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 & don’t differentiate between acute & chronic changes

Parameters of anthropometryAge dependent factors:-a) Weightb) Heightc) Head circumference d) Chest circumference

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

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)

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

•Growth Velocity :

A.0-4 months 1.0kg/month(30g/day) 5-8 months 0.75kg/month(20gm/day) 9-12 months 0.50kg/month(15g/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

WEECH’S FORMULAa) 3 – 12 months

Expected weight(kg) = age (months) + 9 / 2b) 1- 6 years Expected weight(kg) = age (years) x 2 + 8c) 7 – 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%<50%

NormalGrade 1 (Mild)Grade 2 (Moderate)Grade 3 (Severe)Grade 4 (very severe)

Length or Height/Stature Measurement Technique

• Upto 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 .

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 ⁰plank of infantometer is snuggly apposed against soles and length is read from scale.

Technique for height measurement• In 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.

Height VelocityA

At birth 50cms

Gain during 1st year 25cms

Gain during 2nd year 12.5cms

Gain during 3rd year 7.5 to 10cms

Gain during 3 – 12 years 5 to 7.5cms

Adolescence 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 ( wheech’s formula )

C] ] Prediction of adult height

• Parental height , Tanner’s formula and Weech’s formula are used.

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.

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 (Dine’s formula) is used for estimating the head circumference in the first year of life : - ( length in cm + 9.5 ) ± 2.59 2

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 circumference• It is usually measured at the level of nipples,

preferably in mid inspiration.• Xiphisternum• In children <= 5years - lying down position > 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.

• 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.

AGE INDEPENDENT CRITERIA FOR ASSESSMENT OF NUTRITIONAL STATUS• Mid-upper arm circumference• Thickness of subcutaneous fat• Body ratios• Weight for height• Body mass index• Upper segment/ lower segment ratio• Arm span• Obesity

MID-UPPER ARM CIRCUMFERENCE• During 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.

• 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.

levels• The malnourished child would be taller than the anticipated height

derived from the mid-arm circumference

MAC (cm) Ht. (cm)

16.5 133.0

13.5 103.5

12.5 70.0

Skinfold thickness• Measured with Herpenden’s caliper• Triceps 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 <6mm - is indicative of moderate to

severe degree of malnutrition

Body ratios• Rao & Singh’s 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 0.331

Mild 0.310 – 0.280

Modreate 0.279 – 0.250

Severe < 0.250

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

The nutritional status can be expressed as follows on the basis of weight-for-height: Weight-for-Height * Nutritional Status>90%85-90 %75-80 %<75 %

NormalBorderline MalnutritionModerate MalnutritionSevere Malnutrition

*Reference standard NCHS data

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)³ • In malnourished small-for-date babies (asymmetric

IUGR), ponderal index is <2, while it is usually more than 2.5 in term appropriate-for-gestation babies and hypoplastic small-for-date babies.

PROPORTIONAL TRUNK AND LIMB GROWTH•The 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.

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

1. Achondroplasia2. Cretinism3. Short limbed dwarfism4. Sexual precocity5. Bowed legs

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

1. Arachnodactyly2.Hypogonadism3.Eunuchoidism4.Turner Syndrome5.Klinefelter’s Syndrome6.Chondrodystrophy7.Spinal deformities (rickets, pott’s 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.

•Abnormally large arm span is seen in patients with 1)Arachnodactyly (Marfan syndrome)2)Eunuchoidism3)Klinefelter’s Syndrome4)Coarctation of aorta

•Arm span is short compared to height in patients with :1)Short limbed dwarfism2)Cretinism3)Achondroplasia

ADVANTAGES OF ANTHROPOMETRY• Less 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 Anthropometry

Inter-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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