Anthropometric assessments

Anthropometry is a key component of 'nutritional status assessment' in children and adults. It is the study of the measurement of the human body in terms of the dimensions of bone, muscle, and adipose (fat) tissue. It consists of a variety of human body measurements such as 

• Weight 
• Stature (standing height) 
• Recumbent length 
• Skinfold thicknesses 
• Circumferences (head, chest, waist, limb, etc.) 
• Limb lengths, and 
• Breadths (shoulder, wrist, etc.).

Age-dependent factors:

1. Weight

2. Height/ Lenght

3. Head circumference

4. Chest circumference

Age-independent factors:

1. Mid-arm circumference (1-5 years)

2. Weight for height

3. Skinfold thickness

4. Mid-upper-arm/ height ratio

General Precautions to be taken before measurements:

1.Placement of the measuring board and electronic scale: 

Make sure there is adequate light and ensure you place the equipment on a flat and even surface. 

2. When to weigh and measure: 

Weights and heights of all eligible children age in the household will be measured after the history taking. Do not weigh and measure at the beginning.

3. Weigh and measure one child at a time.

4.  Controlling and taking care of the child: 

A gentle but firm approach is necessary. 

5. Coping with stress:  

If a child is under severe stress and is crying excessively, attempts to calm the child should be made. Do not weigh or measure a child if: (a) The mother refuses. (b) The child is too sick or too distressed. (c) The child is physically deformed.

6. Take good care of the equipment and keep it clean.

7.  Strive for improvement: 

Follow every step of every procedure the same way every time. The quality and speed will improve with practice. 

8. Hygiene: 

Carry wet napkins/wipes, an alcohol-based hand gel, or similar to clean hands before and after handling a child. 

Procedures of anthropometric measurements:

1. Weight:

The measurement of weight is the most reliable criteria for the assessment of the health & nutritional status of the children.

The weight can be measured using 

(a) Beam type weighing balance 

(b) Electronic weighing scales for infants & children

(c) Bathroom type of mechanical scale (very unreliable)

(d) Salter spring machine (in field conditions)

(i) For children <2 years of age:

Weighing a child using a taring scale:

• The scale should be placed on a flat, hard, even surface. There must be enough light.
• Explain all procedures to the mother and enlist her help.
• Babies should be weighed naked; wrap them in a blanket or other clothing until weighing. 
• If the child is less than 2 years old, do the tared weighing.

1. To turn on the scale, when the number 0.0 appears, the scale is ready. 
2. The mother will remove her shoes and step on the scale to be weighed first alone. (Have someone else hold the undressed baby wrapped in a blanket.)
3. Ask the mother to stand in the middle of the scale, feet slightly apart (on the footprints, if marked), and to remain still. (Remind her to stay on the scale even after her weight appears, until the baby has been weighed in her arms.)
4. With the mother still on the scale and her weight displayed, tare the scale. The scale is tared when it displays a figure 0.0. 
5. Hand the undressed baby to the mother and ask her to remain still. 
6. The baby’s weight will appear on the display (shown to the nearest 0.1 kg). Record this weight. 

Note: If a mother is very heavy (e.g. more than 100 kg) and the baby’s weight is relatively low (e.g. less than 2.5 kg), the baby’s weight may not register on the scale. In such cases, have a lighter person hold the baby on the scale. 

(ii) For children >2 years of age:

• Older children should be weighed with minimal clothing. If it is socially unacceptable to undress the child, remove as much clothing as possible. 
• If the child is 2 years or older and will stand still, weigh the child alone. 
• If the child jumps on the scale or will not stand still, use the tared weighing procedure instead. 

1. Ask the mother to help the child remove shoes and outer clothing. 
2. Talk with the child about the need to stand still. 
3. Turn on the scale, when the number 0.0 appears, the scale is ready. 
4. Ask the child to stand in the middle of the scale, feet slightly apart (on the footprints, if marked), and to remain still until the weight appears on the display. 
5. Record the child’s weight to the nearest 0.1 kg.

2. Height:

Summary of procedures:

Two persons needed for the measurements:

• Place the measuring board on a hard flat surface against a wall, table, tree, staircase, etc. Make sure the board is stable. 
• Ask the mother/caretaker to remove the child’s shoes and socks. Then ask her/him to walk the child to the board and to kneel in front of the child.
• Place the questionnaire and pen on the ground (Arrow 1). Kneel with both knees on the child’s right side (Arrow 2).
• Kneel on your right knee only, for maximum mobility, on the child’s left side (Arrow 3).
• Place the child’s feet flat and together in the centre of and against the back and base of the board. 
• Place your right hand just above the child’s ankles on the shins (Arrow 4), your left hand on the child’s knees (Arrow 5), and push against the board. 
• Make sure the child’s legs are straight and the heels and calves are against the board (Arrows 6 and 7). 
• Tell the measurer when you have completed positioning the feet and legs.
• Tell the child to look straight ahead at the mother if she is in front of the child. Make sure the child’s line of sight is level with the ground (Arrow 8). 
• Place your open left hand on the child’s chin. Gradually close your hand (Arrow 9). 
• Do not pinch the jaw. Do not cover the child’s mouth or ears. Make sure the shoulders are level (Arrow 10), the hands are at the child’s side (Arrow 11), and the head, shoulder blades, and buttocks are against the board (Arrows 12, 13 and 14). 
• With your right hand, lower the headpiece on top of the child’s head. Make sure you push through the child’s hair (Arrow 15).
• Check the child’s position (Arrows 6-14). Repeat any steps as necessary.
• When the child’s position is correct, read and call out the measurement to the nearest 0.1 centimetre. 
• Remove the headpiece from the child’s head, your left hand from the child’s chin and support the child during the recording.

(Immediately record the measurement in AN4 and show it to the measurer. Alternatively, the assistant could call out the measurement and have the measurer confirm by repeating back.)

• Record in AN4A whether the child was measured lying down or standing up.
• Check the recorded measurement on the questionnaire for accuracy and legibility. Instruct the assistant to cancel and correct any errors.

NOTE: If the interviewer is not confident in the precision of the child’s age (over age 2), please take measurement as described above. If the child’s height is measured to less than 85 cm, you must instead measure the child’s length.

3. Length:

Summary of procedures: 

Two persons needed for the measurements:

• Place the measuring board on a hard flat surface, such as the ground, floor or a steady table.
• Place the questionnaire and pen on the ground, floor, or table (Arrow 1). 
• Kneel with both knees behind the base of the board, if it is on the ground or floor (Arrow 2).
• Kneel on the child’s right side so that you can hold the foot piece with your right hand (Arrow 3).
• With the mother’s/caretaker’s help, lay the child on the board by doing the following:
• Support the back of the child’s head with your hands and gradually lower the child onto the board.
• Support the child at the trunk of the body.
• Ask the mother/caretaker to kneel on the opposite side of the board facing the measurer to help keep the child calm.
• Cup your hands over the child’s ears (Arrow 4). 
• With your arms comfortably straight (Arrow 5), place the child’s head against the base of the board so that the child is looking straight up. 
• The child’s line of sight should be perpendicular to the ground (Arrow 6). 
• Your head should be straight over the child’s head. Look directly into the child’s eyes.
• Make sure the child is lying flat and in the center of the board (Arrow 7). 
• Place your left hand on the child’s shins (above the ankles) or on the knees (Arrow 8). 
• Press them firmly against the board. With your right hand, place the foot piece firmly against the child’s heels (Arrow 9).
• Check the child’s position (Arrows 4-9). Repeat any steps as necessary.
• When the child’s position is correct, read, and call out the measurement to the nearest 0.1 centimeters. 
• Remove the foot piece, release your left hand from the child’s shins or knees, and support the child during the recording.
• Immediately release the child’s head, record the measurement in AN4 and show it to the measurer. 
• Alternatively, the assistant could call out the measurement and have the measurer confirm by repeating back.
• Record in AN4A whether the child was measured lying down or standing up.
• Check the recorded measurement on the questionnaire for accuracy and legibility. Instruct the assistant to cancel and correct any errors.

NOTE: If the interviewer is not confident in the precision of the child’s age (under age 2), please take the measurement as described above. If the child’s length is measured to 85 cm or more, you must instead measure the child’s height.

4. Mid-arm circumference:

Mid-Upper Arm Circumference (MUAC) Procedure:

• Keep your work at eye level. Sit down when possible. (Very young children can be held by their mother during this procedure.) 
• Ask the mother to remove clothing that may cover the child’s left arm.
• Calculate the midpoint of the child’s left upper arm by first locating the tip of the child’s shoulder (Arrows 1 and 2) with your fingertips. 
• Bend the child’s elbow to make a right angle (Arrow 3). Place the tape at zero, which is indicated by two arrows, on the tip of the shoulder (Arrow 4) and 
• Pull the tape straight down past the tip of the elbow (Arrow 5). Read the number at the tip of the elbow to the nearest centimeter. 
• Divide this number by two to estimate the midpoint. As an alternative, bend the tape up to the middle length to estimate the midpoint. 
• A piece of string can also be used for this purpose. Either you or an assistant can mark the midpoint with a pen on the arm (Arrow 6).
• Straighten the child’s arm and wrap the tape around the arm at the midpoint. Make sure the numbers are right side up. Make sure the tape is flat around the skin (Arrow7).
• Inspect the tension of the tape on the child’s arm. Make sure the tape has the proper tension (Arrow 7) and is not too tight or too loose. Repeat any steps as necessary.
• Have the questionnaire ready.
• When the tape is in the correct position on the arm with the correct tension, read and call out the measurement to the nearest 0.1cm. (Arrow 10).
• Immediately record the measurement on the questionnaire and show it to the measurer.
• While the assistant records the measurement, loosen the tape on the child’s arm.
• Check the recorded measurement on the questionnaire for accuracy and legibility. Instruct the assistant to erase and correct any errors.
• Remove the tape from the child’s arm.

5. Head circumference:

Steps for measurement of the head circumference:

• Wash your hands and explain the procedure to the child and parent.
• Use a measuring tape that cannot be stretched.
• Any braids, barrettes, or other hair decorations that will interfere with the measurement should be removed.
• The infant or child may be more comfortable in the arms or on the lap of a parent. 
• Securely wrap the tape around the widest possible circumference of the head. 

1. The broadest part of the forehead above the eyebrow 
2. Above the ears 
3. A Most prominent part of the back of the head 

• The tape is pulled snugly to compress the hair and underlying soft tissues.
  
• Take the measurement three times and select the largest measurement to the nearest 0.1 cm or 1/8 inch.
• Head circumference measurements should be taken on the first day of life because the commonly-used birth head circumference reference charts by age and sex are based on measurements taken before 24 hours of age. 

6. Chest circumference:

Steps for measurement of the chest circumference:

• Wash your hands and explain the procedure to the child and parent. 
• Whilst the child is standing, feel for the xiphisternum where the ribs meet the sternum and mark with a short horizontal line.  
• Pass the tape around so that the mark is at the upper border of the tape. 
• Make sure the tape is level. It should rest on the skin but not indenting it/not pulled too tight. 
• Take the reading at the end of expiration. 
• Measure to the nearest 0.1cm (1mm). 
• Make three measurements of chest circumference. 
• Record the individual measurement and the mean (average) by adding the values together and dividing by three.

7. Waist circumference:

Steps for measurement of the waist circumference:

• Wash your hands and explain the procedure to the child and parent. 
• Always mark both sides; it helps to keep the tape level. 
• Palpate for the lower rib margin (costal margin) and mark with a short horizontal line. 
• Palpate for the iliac crest and mark with a short horizontal line. 
• Using the tape measure, measure the mid-distance between the two horizontal lines and mark this with another short horizontal line in the middle. 
• Ask the child to cross their arms across their chest so that you have access to the waist. 
• Instruct them to stand relaxed and look straight ahead. 
• Try and make sure that they don’t deliberately hold themselves in or out. 
• Pass the tape around the waist, making sure it is level and that it is positioned at the mid-distance mark on both sides. 
• Make sure the tape is not pulled too tight. It should rest on the skin but not indent it. 
• Make the measurement at the end of expiration. 9. Measure to the nearest 0.1cm (1mm). 
• Make three measurements of waist circumference  
• Record all three measurements and the mean (average) by adding the values together and dividing by three.

9. Hip Circumference:

Steps for measurement of the hip circumference:

• Wash your hands and explain the procedure to the child and parent. 
• Make the measurement at the widest part of the hips (usually between the greater trochanter (top of the thigh bone) and the lower buttock level). 
• Make the measurement over pants/knickers or thin shorts with the legs together. 
• Ensure the tape is horizontal all round. 4. Measure to the nearest 0.1cm (1mm). 
• Make three measurements of the hip circumference. 
• Record all three measurements and the mean (average) by adding the values together and dividing by three.

10. Skinfold thickness:

Steps for measurement of the Skinfold thickness:

It includes triceps and subscapular skinfold measures. For participants aged 2 months and older both types of skinfolds are measured in millimeters using the Holtain skinfold caliper.

It's mandatory that the skinfold consists of a double thickness of skin and underlying adipose (fat) tissue.

• Prior to measuring the skinfold, carefully mark the appropriate site with a cosmetic pencil.
• Explain the procedure and demonstrate the use of the caliper on the palm of the child and/or the parent.
• Grasp the skinfold between your thumb and index finger approximately 2.0 cm above the measurement mark. 
• Pull the skinfold away from the body to separate the fat from the underlying muscle. The sides of the fold should be roughly parallel.
• With your free hand, place the caliper jaws perpendicular to the length of the fold.
• Continue to hold the skinfold with your thumb and forefinger. 
• Release the handle of the calipers to apply full tension on the fold and hold this position for approximately 3 seconds.
• During this time the needle on the caliper dial will settle into a final position that represents the true thickness of the fold.
• Take the reading with your line of sight directly in front of the measurement value instead of at an angle. 
• Measure the thickness to the nearest tenth of a millimeter (0.1 mm). Note that the caliper dial shows 0.2 mm increments.
• Before releasing the caliper and your fingers from the skinfold, call the measurement to the recorder.
• Remove the caliper jaws then let go of the fold.

References:

1. https://www.who.int/childgrowth/training/jobaid_weighing_measuring.pdf
2. https://www.who.int/childgrowth/training/module_b_measuring_growth.pdf
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