COMMUNITY NUTRITION 3 (1+2)

Lesson 3 : Analysis and Interpretation of Anthropometric data

Presentation of growth data

Standards of growth employ

1. Percentiles division: Refers to the value of measurement of that particular number in a series of hundred, when they are arranged in an ascending order.
   50th percentile – (Median) referes to the 50th value in a series of 100.
   3rd percentile indicates that 3% of children are below the value and 97% above that value.
   Common percentiles are – 3, 5, 10, 25, 50, 75, 90, 95 & 97th.


2. Standard deviation (SD)
   The relationship of percentiles to S.D in a normally distributed characteristic is shown in figure below.
   3rd & 97th percentile include 94% of the population and coincide with values + or – S.D from the mean.
   Conventionally -2 S.D units are taken as cut offs to determine retardation in growth.

• S.D classification
  Standard deviation (S.D) classification is shown in table below.
  
  

SD Classification	Weight for age	Height for age	Weight for height
≥ Median- 2SD	Normal	Normal	Normal
Median- 2SD to ≥Median- 3SD	Moderate under nutrition	Moderate stunting	Moderate wasting
< Median- 3SD	Severe under nutrition	Severe stunting	Severe wasting

• Percentage deviation from the median of standard
  To classify children into Nutrition grades or grades of deficit (mild, moderate, severe) – by establishing arbitrary cut-off points.
  Ex: Gomez Classification


• Velocity of growth
  Velocity is the rate of growth per unit time, usually one year and is referred to as annual increment.
  It is the difference in the measurements obtained at initial point of time (T1) and at the end of one year (T2), in a longitudinal study.
  Distance Charts: are prepared using data collected in cross sectional studies.
  Children belonging to different ages are measured at one point of time. Means for different ages are plotted on graphs and are joined by a smoothened curve.