ANTHROPOMETRY FOR ASSESSMENT OF NUTRITIONAL STATUS

ANTHROPOMETRY FOR ASSESSMENT OF NUTRITIONAL STATUS

Growth and maturation (development) are the most distinctive attributes of children which distinguish them from adults. The anatomical characteristics and functional maturity of organs at different ages affect the incidence and manifestations of diseases in children and childhood disorders can profoundly and adversely affect the growth and development of children. Protein-energy malnutrition is the core health problem in children which makes them vulnerable to develop a variety of infectious diseases perpetuating a vicious cycle of disease and debility.

ANTHROPOMETRY FOR ASSESSMENT OF NUTRITIONAL STATUSWeight

The measurement of weight is the most reliable criterion of assessment of health and nutritional status of children. The physical growth depends upon the interaction between genetic endowment and environmental influences, especially dietary intake and infectious diseases. Weight is a measure of total body mass and is sensitive to changes in body fluids, fat, muscle mass, skeleton and body organs. The weight may be recorded on a beam type weighing scale (Detecto scale with an accuracy of ±20 g). The scale should be frequently checked with standard weights and zero error must be adjusted before weighing. Electronic weighing scales for infants (± 1 to 5g) and children (± 10 g) are available and should be preferred for their accuracy and convenience. The bathroom type of scale is very unreliable for children and should not be used. In field conditions Salter spring machine is quite satisfactory because it is convenient to carry. The machine is hung from a hook or held by an attendant and baby is placed on the sling attached the bottom hook. The periodic weight record on a growth chart is essential for monitoring the growth of children. Isolated weight record does not provide any information regarding growth velocity or pattern of growth. The boys generally weigh more than the girls upto the age of 10 years. During 12 to 13 years, the girls weigh more than the boys due to early pubertal growth spurt. Depending upon the actual weight of the child, weight age should be expressed by consulting the standard growth chart.

Growth Velocity
A.
0-4 months:  1.0 kg/month (30 g/day)
5-8 months:  0.75 kg/month (20 g/day)
9-12 months:  0.50 kg/month (15 g/day)
1-3 years:  3.0 kg/yr
3-12 years:  2.0 kg/yr
12-18 years:  5.0-6.0 kg/yr (0.5 kg/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

Weight in kg = (Age in years + 3) x 2

The weight-for-age is a reliable index of the nutritional status of a child. The severity of undernutrition can be assessed on the basis of classification proposed by Indian Academy of Pediatrics.

Gomez classification of malnutrition
Weight-for-age* Grade of malnutrition
>80% Normal
71-80% Grade I
61-70% Grade II
51-60% Grade III
<50% Grade IV

*50th  percentile of NCHS data

Length or Height

Upto 2 years of age recumbent length is measured with the help of an infantometer while in older children standing height is recorded. Accurate recording of length is difficult and often unreliable although it is a better index of physical growth. The infant is placed supine on the infantometer. Assistant or mother is asked to keep the vertex snugly touching the fixed vertical plank. The legs are fully extended by pressing over the knees, and feet are kept vertical at 90°, the movable pedal plank of infantometer is snuggly apposed against the soles and length is read from the scale. In practice it is difficult to extend both the legs while it is convenient and staisfactory to extend only one leg to record the length. In older children who can stand, height can be measured by the rod attached to the lever type machine or by an anthropometer or simply making the child stand against a wall on which a measuring scale is inscribed. The child should stand with bare feet on a flat floor against a wall with feet parallel and with heels, buttocks, shoulders and occiput touching the wall .The head should be held erect with eyes aligned horizontally and ears vertically without any tilt. With the help of a wooden spatula or plastic ruler, the topmost point of the vertex is identified on the wall. It is convenient to use an in-built stadometer affixed on the electronic weighing scale which provides a direct read out of height.

Nutritional deprivation over a period of time (generally over 6 months) affects the size or linear growth of the child while acute starvation is associated with weight loss due to wasting or loss of subcutaneous tissue and muscle mass. Depending upon the actual height of the child, the height age should be expressed by consulting the standard height chart.

Height velocity

A.
At birth: 20 inches (50 cm)
Gain during 1st year: 10 inches (25 cm)
Gain during 2nd year: 5 inches (12.5 cm)
Gain during 3rd year: 3.4 inches.(7.5-10 cm)
Gain during 3-12 years: 2-3 inches / year (5.0-7.5 cm)
Adolescence: 8 cm / year girls 10 cm / year boys

B.
Expected height upto 12 years
Length or height (inches) = Age in years x 2.5 + 30
Length or height (cm) = Age in years x 6+ 77

C.
Prediction of adult height

(a) The calculation of mid-parental height is useful to evaluate the child’s genetic endowment for linear growth. The determination is made by using the following formulae:

Boys = (Mother’s height in cm+13 cm) + (Father’s height in cm) / 2
Girls = (Father’s height in cm -13 cm) + (Mother’s height in cm) / 2

The projected adult height by this method corresponds to within ± 8cm or 2 SD.

(b) Tanner’s formula
Adult height = height at 2 years x 2
Adult height = height at 3 years x 1.37

(c) Weech’s formula
Adult height in inches
Boys = 0.545 H3 + 0.544 A + 14.84
Girls = 0.545 H3 + 0.544 A + 10.09

wherein H3 is height of the child at 3 years and A refers to mean height of parents

Head circumference

The brain growth is very rapid during infancy and it is unaffected by mild to moderate degrees of undernutrition. The marasmic children are seen to have relatively large head for their body size. During states of undernutrition of varying severity, weight (subcutaneous fat and muscles), linear growth (height) and brain growth are affected in that order. The closure of anterior fontanel is often delayed in children with PEM and vitamin D deficiency. The occipitofrontal head circumference should be measured with a fibre-glass tape. The tape should encircle over the most prominent part of occiput and supraorbital frontal areas. Depicts the normal range of head circumference in under- five children.

Head circumference (cm) in under-five children (10th-90th percentile)
Birth 32.0-35.5
1 month 34.0-37.5
2 months 36.0-39.5
3 months 38.0-41.5
6 months 40.0-43.5
9 months 42.0-45.0
1 years 43.5-46.5
1½ years 44.5-48.0
2 years 45.5-49.0
2½ years 46.5-50.0
3 years 46.8-50.3
3½ years 47.1-50.6
4 years 47.5-50.9
4½ years 47.8-51.2
5 years 48.1-51.5

Head circumference growth velocity

Till 3 months:  2 cm / month
3 months – 1 year:  2 cm / 3 months (1/3 of initial velocity)
1 – 3 years:  1 cm / 6 months (1/12 of initial velocity)
3-5 years:  1 cm / year (1/24 of initial velocity)

During first year there is 12 cm increase in head circumference, while between 1-5 year age, only 5 cm gain occurs in head size. Adult head size is achieved between 5 to 6 years.

Relationship of Head Size with Chest Circumference

At birth head circumference is larger by upto 3 cm as compared to chest circumference. The head circumference is larger by more than 3 cm as compared to chest circumference at birth in preterms, small-for-dates and hydrocephalic infants. The chest circumference equals head circumference around 9 months to 1 year of age but thereafter chest grows more rapidly as compared to the brain. In preterm babies chest circumference may exceed head circumference between 6 to 9 months of age. In malnourished children, chest size may be significantly smaller than the head circumference because growth of the brain is less affected by undernutrition. Therefore, there will be considerable delay before chest circumference overtakes head circumference. The chest circumference is measured at the level of nipples.

Age-independent Criteria of Malnutrition

In developing countries, date of birth and hence accurate age of the child is often unknown thus invalidating above referred parameters. The rough age may be deduced by using a local calender of events, seasons and festivals. In case the mother is totally ignorant about the age of the child, the following age-independent parameters can be utilized to assess the nutritional status of the child.

Mid-upper Arm Circumference

During 1-5 years of age, the mid-upper arm circumference (MU AC) remains reasonably static between 15-17 cm among healthy children because fat of early infancy is gradually replaced by muscles. Mid-upper arm circumference is measured with a fibre glass or steel tape at the midpoint between acromian and olecranon. The tailor’s tape is not accurate and should not be used. If the circumference of the upper arm is less than 12.5 cm, it is suggestive of severe malnutrition while MU AC between 12.5 -13.5 cm is indicative of moderate malnutrition.

Bangle test can be used for quick assessment of arm circumference. A fibreglass 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 fibre-glass tape with red (less than 12.5 cm), yellow (12.5- 13.5 cm) and green shading so that paramedical workers can assess nutritional status without having to remember the normal limits of mid-arm circumference.

Arm circumference for different heights
Mid-upper arm circumference (cm) Height (cm)
16.50
16.00
15.50
15.00
14.75
14.50
14.25
14.00
13.75
13.50
13.25
13.00
12.75
133.00
129.00
125.00
121.00
118.00
116.00
113.50
110.00
106.50
103.50
97.50
90.00
80.00

Quac stick

It is developed on the principle that acute starvation severely affects mid-arm circumference while height is unaffected. The child appears tall, thin and wasted. The Quac stick is a meter rod with two sets of markings. The expected height of the child against various sizes of mid-arm circumference is inscribed on the rod. The malnourished child would be taller than the anticipated height derived from the mid-arm circumference.

Thickness of subcutaneous fat

The subcutaneous fat thickness is measured with Herpenden’s caliper over the triceps or subscapular region. The fat-thickness is 10 mm or more among healthy children between 1-6 years of age. If it is less than 6 mm it is indicative of moderate to severe degree of malnutrition.

Body ratios
They are complicated and often unreliable.

Weight-for-height
Weight for height is expressed as a percentage of the reference median weight expected on the basis of height of the patient and is calculated as follows:

The nutritional status can be expressed as follows on the basis of weight- for-height:

 
Weight-for-height* Nutritional status
>90% Normal
85-90% Borderline malnutrition
75-80% Moderate malnutrition
<75% Severe malnutrition

* Reference standard NCHS data

Weight-for-Height and Height-for-Age Classification

When malnutrition has been chronic, the child is “stunted”, both his weight- for-age and height-for-age are low but his weight-for-height is usually normal. In acute malnutrition, however, his height-for-age is appropriate but he is “wasted” and underweight both for his age and height. Based on the dynamics of malnutrition, Waterlow has proposed a useful classification of malnutrition and stunting.

Proportional Trunk and Limb Growth

The upper segment (vertex to upper edge of symphysis pubis) to lower segment (limb length i.e. symphysis pubis to heels) ratio at birth is 1.7 to 1.0. There is gradual reduction in the ratio (due to rapid epiphyseal or limb growth

Waterlow’s classification of nutritional status based on height-for-age and weight-for-height data
Parameter Value* Nutritional status
Weight-for-height
Height-for-age
>80%
>90%
Normal
Weight-for-height
Height-for-age
>80%
<90%
Stunted
Weight-for-height
Height-for-age
<80%
>90%
Wasted
Weight-for-height
Height-for-age
<80%
<90%
Wasted and stunted

*Reference standard NCHS data

by 0.07-0.10 every year till ratio is around 1:1 at 10-12 years. Among healthy adults the usual stem to limb ratio is 1.0 to 1.1. In infants upper segment can be measured by using infantometer as shown in. 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 achondroplasia, cretinism, shortlimbed dwarfism, bowed legs while advanced upper segment to lower-segment ratio (trunk abnormally short or limbs abnormally long) is seen in arachnodactyly, eunuchoidism, chondrodystrophy, and spinal deformities (rickets, Pott’s spine).

It is the distance between the tips of middle fingers of both arms outstretched at right angles to the body. The arm span is measured across the back of the child. In under-5 children, span is 1 to 2 cm smaller than body length. During 10-12 years of age, span is equal to the height while in adults span is more than height by 2 cm. Abnormally large span is seen in patients with arachnodactyly, eunuchoidism, Klinefelter’s syndrome, and coarctation of aorta (due to relative over growth of upper extremities).

Obesity

It is true that protein-energy-malnutrition is a public health problem or a core health problem in children in developing countries. Nevertheless, over nutrition or obesity is being increasingly recognised in children belonging to affluent families having unhealthy dietary practices (intake of calorie-dense snackes and junk food) and life style. There is no satisfactory or standard definition for obesity in children. A weight-for-height of greater than 2 SD of NCHS data (>+2z scores) or above 95th percentile is suggestive of obesity. The WHO expert committee recommend the use of body mass index-for-age. Body mass index (BMI) is calculated as weight in kg/(height in meters)2. A BMI-for-age of > 85th percentile is suggestive of overweight and when it is associated with triceps or subscapular skinfold thickness-for-age of >90th percentile, it is diagnostic of adolescent obesity. The constitutional or nutritional obesity should be differentiated from pathological or endocrinal obesity. Pathological obesity during infancy is easy to diagnose and is often due to endocrinal causes or known syndromes. Apart from adverse psychological effects and

  Differences between constitutional or familial obesity from pathological or
endocrinal obesity
Feature Constitutional or familial obesity Pathological or endocrinal obesity
• Family history May be present Usually absent
• Eating behavior Excessive or fast and faulty eating habits, lazy life style Eating normal or voracious, activity is effected after the onset of obesity
• Distribution of fat Generalized “Buffalo hump” because of greater deposition of fat over face and cervico-dorsal area.
• Height Usually increased with advanced bone age Usually decreased with retarded bone age.
• Blood pressure Normal May be raised
• Endocrinal effects Nil Acne, hirsutism, amenorrhea or menstrual irregularity.
• Hypogonadism None but penis may be embedded in the pubic pad of fat. May be associated in some syndromes . (Prader-Willi syndrome, Alstrom syndrome, GH deficiency, Laurence-Moon-Biedle syndrome, hypothalamic disorders)
• GNS features None Excessive sleepiness, hydrocephalus with visual field defects (SOL due to craniopharyngioma, pituitary tumor),papilledema or retinal degeneration, and mental retardation in association with certain syndromes (encephalitis, Prader-Willi syndrome, Vaquez syndrome, Laurence- Moon-Biedle syndrome)

orthopedic complications, obesity is a recognized risk factor for non-insulin dependent diabetes mellitus, hypertension, coronary artery disease and development of some cancers in adulthood.