Anthropometry

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59 world, was designed to provide a description of how children should grow under optimal conditions. The WHO Child Growth Standards can therefore be used to assess children all over the world, regardless of ethnicity, social and economic influences, and feeding practices unlike the NCHS standards which was based on the standards of one country.²²³

The main idea of the new WHO standards is to see how children should be growing for the best health outcome, rather than just showing how the average child is growing. It also takes into consideration the use of length / height and body mass index (BMI) which was never used in the NCHS standards. The growth charts therefore include length or height for age, weight for age and weight for length or height and looks at the milestones that children should reach at specific ages which was absent in the NCHS standards.²²⁴

A child who has Z-scores within ± 1SD is within the normal range. Children with the lower portion of these ranges are classified as “moderately malnourished”. Children who are more than 3SD below the normal have severe malnutrition. In children older than six months, a deficit of 5% in height-for-age or 10% in weight-for-height is more or less equal to one Z-score.^202,208 The accepted anthropometric cut-off for the diagnosis of undernutrition is –2SD (z score) and indicates an increased risk of morbidity and mortality.²²⁰

The WHO Reference 2007 provides a smooth transition from the child growth standards for 0-5 years to the older age group. The data tables and charts cover the 1st to the 99th percentile and from -3 to +3 standard deviations (SD). In older children, i.e. above 10 years, weight-for-age is not a good indicator as it cannot distinguish between height and body mass in an weight-for-age period where many children are experiencing the pubertal growth spurt and may appear as having excess weight (by weight-for-age) when in fact they are just tall. BMI-for-age is the recommended indicator for assessing thinness, overweight and obesity in children 10-19 years.

For BMI for-age the recommended cut-offs for overweight and obesity are not the same as in preschool children. For children 5-19 years the +1 SD in the WHO reference (equivalent to the

60 85th percentile) coincides at 19 years with the adults cut-off of BMI =25 [kg/m2], which is the cut-off for overweight. Similarly, the +2 SD (equivalent to the 97th centile) coincides at 19 years with the adults cut-off of BMI=30 [kg/m2], which is the recommended cut-off for obesity. Consequently the +3 SD cut-off will be considered severely obese (corresponding to a BMI of above 35 [kg/m2]). For thinness and severe thinness the cut-offs are -2 and -3 SD, respectively.²²⁵

3.3.1.2 Indices of Undernutrition

Percentile: In weight-for-age graphs, the average is the 50^th percentile (i.e. median) of the reference sample. An individual’s difference up or down from this median can be read firstly from the percentile lines.

Standard deviation: Another way to measure distance from the median is the standard deviation or Z-score above or below the median.

Percentage of the median: A third indicator used for undernutrition is not percentile of the reference children but percentage of the median i.e. of the 50th percentile, the international standard.

Below 80% of the median, a child is ‘underweight’; this weight is near the 3rd percentile line and near a Z-score of -2.²²⁶

3.3.1.3 Weight

Anthropometry provides a way of estimating the magnitude of a deficiency.²²¹ Weight-for-age is most often used as an indicator of children’s nutritional status and it is the most widely used in developing countries.²²⁷ The NCHS standards show the child’s anthropometry as a percentage of the median for the standard population. According to the WHO, appropriate weight and weight-for-height reflects proper body proportion because weight-for-height is sensitive to acute growth changes.²²⁰

61 Severe acute malnutrition is defined by a very low weight-for-height seen as <-3 Z-score of the median of the NCHS or WHO standards. It is also classified by the presence of visible severe wasting, or the presence of nutritional oedema.²²⁸ Weights are recorded to the nearest 0.01 kg in infants and 0.1 kg in older children.²²⁹

3.3.1.4 Stature: Height/ Length

Height is measured in infants and young children less than 24 months of age by taking recumbent or supine length when the child is lying down, whether they can stand or not. It is measured in children two years to five years in a standing position.²²⁶When a measuring board is used, the child must be held firmly to make sure that the head and feet are touching the head and foot panels respectively and the knees are kept down.²³⁰

Height measurement can be used with weight to measure overall growth for comparison to growth standards.²³⁰ According to the WHO, the appropriate height for- age of a child reflects linear growth, and can therefore measure long-term growth faltering or stunting.²³⁰

3.3.1.5 Mid Upper Arm Circumference (MUAC)

The MUAC works well in field conditions where no scale is available. MUAC is not sensitive, but it can differentiate between moderately and severely malnourished.²⁰¹ MUAC is the circumference of the left upper arm, measured at the mid-point between the tip of the shoulder and the tip of the elbow (olecranon process and the acromium).²³¹

MUAC is a better prognostic indicator for mortality than weight-for-height ^202,231, or any other anthropometric indicator as reported by Mother and Child Nutrition 2012. ²³¹

There is very little change in a child’s arm circumference between the ages of one to five years.

This measurement therefore gives a simple measure of wasting. Children between twelve to 59 months old can be screened using the MUAC and when a child is older than six months but longer than 65cm, the MUAC can also be used.²³²

62 According to the WHO, children aged six to 59 months, with an arm circumference less than 110mm are severely and acutely malnourished.²¹³, and it is the best indicator for identifying children at high risk of death from malnutrition in underprivileged communities.²³³

3.3.1.6 Head Circumference

Head growth, primarily owing to brain development, is most rapid within the first 3 years of life. Routine measurement of head circumference (the frontal occipital circumference) is a component of the nutritional assessment in children up to age 3 and longer in children who are at high nutritional risk. In determining short-term nutritional status, head circumference is a less sensitive indicator than weight and height because brain growth is generally preserved in cases of nutritional stress. Head circumference is not a helpful nutritional status measure in children with hydrocephalus, microcephaly, and macrocephaly.²³⁰

It is measured using a flexible, nonstretch tape measure. The circumference should be taken at the maximum distance around the head, which is found by placing the measuring tape above the supraorbital ridge and extending around the occiput.^{234, 235} Care should be taken to keep the tape measure flat against the head and parallel on both sides and the measurements should be recorded to the nearest 0.1 cm.²³⁵