34 Nutritional Status assessment of children and Adults

Dr. Mallikarjunar Rao

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Learning outcome

 

  • After studying this module the participant should be able to:
  • Know different methods for assessment of nutritional status
  • Measurement techniques of Nutritional Anthropometry
  • Various anthropometric indices useful in the assessment of nutritional status
  • Advantages of anthropometry in the assessment of nutritional status

Malnutrition is one of the major public health problems in most of the developing countries, including India. ‘Assessment’ of nutritional status of the community assumes an important role in understanding the nature of the problem and its magnitude, geographical distribution and distribution among different age, gender and physiological groups. ‘Analysis’ of data and identification of at risk groups and causative factors is essential for prioritization, development and targeting of appropriate ‘Action’ programmes for prevention and control of malnutrition.

 

There are ‘direct’ and ‘indirect’ methods for assessing nutritional status of a community. Direct methods

 

  1. Prevalence of clinical signs
  2. Nutritional anthropometry
  3. Bio-chemical tests
  4. Bio-physical methods

 

Indirect methods

 

  1. Vital Statistics, such as:
  2. Morbidity rates
  3. Mortality rates
  4. Assessment of ecological factors, such as:
  5. Food and nutrient consumption
  6. Household food security
  7. Socio-cultural factors
  8. Medical and educational facilities etc.
  9. Food production
  10. Socio-economic factors

 

No single method can provide a complete picture of nutritional status of the community and hence it is necessary to use a combination of methods, keeping in view the objectives and availability of resources. However, in the present module nutritional anthropometry is discussed in detail.

 

Nutritional Anthropometry

 

Procedures for taking anthropometric measurements

 

Growth retardation may be first response of the body towards nutritional deficiencies while appearance of clinical signs may be the final stage. From the public health point of view, identification of sub-clinical forms of malnutrition is very important for planning programmes of nutrition intervention so as to prevent such milder cases going into severe forms with consequent risk of high mortality. Anthropometric measurements i.e. body measurements are the most widely used means, to assess nutritional status. Use of anthropometric measurements depends on two factors:

 

  1. Accurate age assessment, especially in case of preschool age children.
  2. Appropriate instruments,
  3. Standardization of anthropometric techniques,
  4. Use of WHO Child Growth Standards (for <5 year)/reference values (for older age groups) and
  5. Appropriate classifications for grading nutritional status

 

Assessment of Age

 

Elicit correct age of all the family members. In case of children below 5 years, age should be assessed up to nearest completed month based on authentic documents such as birth certificate, horoscope, immunization card and hospital record. In the absence of the above, the age should be assessed with the help of local events calendar prepared for the past 5 years (model copy is provided at the end of this manual), based on different fairs, festivals, or other important local events. In the case of individuals who are above the age of 5 years, assess the age up to completed years.

 

Growth Standards

 

Use of body measurements like weight, height etc., is meaningful only if the actual measurements obtained on an individual are compared with known normal values. These normal values are referred to as growth standards or reference values and are obtained by surveying a large number of well-fed, healthy children who are medically and socially well protected. Generally it is now accepted that the growth potential of well-fed children in all the countries are similar and comparable. In the past, NCHS reference values were used to assess the nutritional status of individuals of different age groups and gender. Currently, WHO Child Growth Standards are being used all over the world to assess the nutritional status of children up to 5 years. In case of school age children and adolescents (5-19 year age group), WHO recommended Age/Sex specific BMI centile values are used for grading nutritional status.

 

Measurement of Height / Length

 

Height is measured up to the nearest millimeter, using anthropometric rod. In case of children of less than 2 years of age recumbent length is measured by using infantometer.

 

Procedure

 

Ask the subject to stand erect on a flat surface with heels together and upper limbs hanging closely to the sides of the body. The investigator should stand on the left side of the subject.

 

The anthropometer rod (after assembling the four pieces and the sliding head piece properly), held in the right hand, should be placed at the back of the subject, touching heels, buttocks and back of the head. The chin of the subject should be held by left hand and the occipital protuberance is supported by the little finger of the right hand, while holding the rod with thumb and index finger. The head should be positioned such that the imaginary line drawn from tragus of the ear to the infra-orbital margin i.e. lower border of the socket of the eye (Frankfurt horizontal plane) is parallel to ground.

 

By holding the head in this position, a gentle upward pull is applied (taking care that the subject does not lift his/her heels) to straighten any curvature in the spinal cord. Then the sliding headpiece of the rod is brought down so as to touch the crown firmly pressing the hair, taking care that the blade is in the sagital plane (mid-line) of the body. At this juncture, the height is read from the window of the headpiece. This process is repeated thrice and the consistent reading is obtained. Record the height in centimetres up to nearest mm.

Measurement of recumbent length

 

The ‘height’ of young children (below two years) is measured as ‘recumbent Length’ using an infantometer. The child is laid on its back on the flat surface of the infantometer with head touching the fixed head board and legs towards the movable sliding board. The infant’s head is held firmly against the fixed head board by a helper. The investigator should hold the infant’s knees gently pressed down against the board with his left hand and the foot board is moved with the right hand so that it comes in contact with the soles of the infant at right angles. The measurement is recorded in centimetres up to nearest mm.

Measurement of weight

 

Weight is the important anthropometric measurement most in use. Use of lever-actuated balance with 100gm of accuracy is recommended. In case of birth weights, an accuracy of at least 20 g is recommended. The weighing scale should be placed on a firm and flat ground and zero-error has to be adjusted.

  • The subject is made to stand on the platform of the balance with out footwear and with minimal clothing.
  • In case of children, ensure that he/she does not hold any other person for support.
  • The weights should be recorded to the nearest 100 g.
  • In case of very young children and children who do not co-operate, weight should be taken along with an adult carrying the child. The adult’s weight is then deducted from the total weight, to get the child’s weight.

Measurement of Mid-upper arm circumference

 

Mid arm circumference should always be measured on left arm using fibre reinforced plastic tape up to nearest mm.

 

The subject is asked to stand erect and the investigator stands on the left side. The left arm is folded at right angle at elbow, keeping close to the body. Distance from tip of the bony prominence of shoulder (tip of Acromion process) to the tip of the bony prominence of the elbow (tip of Olecranon) is measured. Keeping the tape in position, mid point is marked horizontally (half of the distance measured above). Then the arm is straightened and placed by the side of the body hanging loosely. Tape is passed round the arm at the mid-point such that it closely covers the arm, without applying too much of pressure or keeping it loose. The tape should not be elliptical but kept horizontal. The reading on the tape corresponding to ‘0’ mark is the arm circumference.

Measurement of Waist Circumference

 

In the recent past, particularly with increasing incidence of obesity, considering the significance of abdominal adiposity in diet related chronic diseases, waist and hip circumferences are used to evaluate the abdominal adiposity in subjects.

The subject should stand erect with weight evenly balanced on both feet, which are placed about 25-30 cms apart. Mark the level of the lowest rib margin. Feel the iliac crest in the mid-axillary line and make a mark. Pass the measure tape around the waist horizontally midway between the lowest rib margin and iliac crest and measure the circumference in Centimetres up to the nearest mm. It is advised that the observer should sit on a stool in front of the subject while taking the measurement.

Measurement of Hip Circumference

Place the tape horizontally over the buttocks and measure the circumference at the point yielding the maximum circumference in centimetres up to the nearest mm.

Measurement of fat fold at triceps (FFT)

The FFT is measured on the left arm using Skin fold caliper. A number of skin fold calipers are available. But Harpenden’s and Holtain calipers are recommended.

A vertical fold of skin is held with left thumb and index finger, one inch above the mid-point on mid-line on the back of the left arm of the subject, taking care not to include muscle. The caliper is held with right hand, horizontal to the ground and is pressed to open the contact surfaces. The caliper is applied to the skin fold and is released slowly so that the contact surfaces touch the middle of the skin fold, taking care not to be too close to the arm or too close to the edge of the skin fold. The reading should be noted immediately as any delay will lead to gradual decrease in the measurement. This procedure is repeated thrice and the consistent reading is recorded in mm up to the first decimal.

Anthropometric indices/classifications

 

Distance charts can be prepared for median anthropometric measurements according to age/sex in comparison with WHO child Growth Standards, in the form of line diagram.

 

Preschool Children: The 1-5 year children are categorized in to different nutritional grades according to weight for age by Gomez Classification, Indian Academy of Pediatrics (IAP) classification and according to Standard Deviation (SD) Classification for weight for age, Height for age and weight for height as described below:

 

Standard Deviation (SD) Classification

 

The World Health Organization recommends use of SD classification to categorize the children into different grades of nutritional status. The percent distribution of preschool children according to undernutrition (weight for age), stunting (height for age) and wasting (weight for height) will be computed using WHO Child Growth Standards, as given below:

IAP Classification

 

ICDS growth charts are based on IAP classification using unisex Harvard standards. The children of 0-60 months are categorized in to various nutritional grades according IAP classification, as follows, to help comparison with ICDS data:

School age Children and Adolescents

 

The school age children and adolescents (5-19 years) may be categorized into various grades of nutritional status according to the BMI in comparison with age/gender specific centile values recommended by WHO, as given below.

 

Adults

 

Body Mass Index (BMI)

 

The adult males and females may be categorized according to nutritional status based on Body Mass Index (BMI), as suggested by James et al (1988) classification is, as follows:

Waist Circumference (WC)

 

A cut-off level for waist circumference of ³102 cm for adult men and ³ 88 cm for women is recommended to identify individuals as having abdominal obesity (BMJ, Vol 311, pp1401, 1995). However, for South Asians, WHO recommends cut off levels of ³ 90 cm for adult men and ³ 80 cm for women, to define abdominal obesity (Lancet, vol. 366, pp1059-1069, 2005).

 

Waist-hip Ratio (WHR)

 

All the adult males with waist-hip ratio of ³ 0.95 and women with ³ 0.80 will be identified as obesity.

 

Advantages of Anthropometry

  1. The procedures are simple, safe, non-invasive techniques and are applicable to large sample sizes.
  2. The equipment is inexpensive, portable, durable and can be purchased locally.
  3. Relatively unskilled personnel can perform measurement procedures.
  4. The methods are standardized and are precise and accurate.
  5. The procedures are good in identifying mild, moderate and severe forms of malnutrition.
  6. The procedures are useful in understanding the changes in Nutritional Status over periods of time (Secular Trends).

 

Biochemical Tests

 

Most of the nutritional deficiencies are characterized by changes in body fluids and tissues. These changes can be used to assess the nutritional status of an individual. The commonly used biochemical indices are estimation of Haemoglobin, serum albumin, serum vitamin A etc.

 

Biophysical Methods

Nutritional assessment may occasionally include selected biophysical methods to measure body composition, bone mineral density, physical work capacity etc.

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