Chapter 6 – Anthropometric Body Measurement Assessment

Children and Body Measurements

Anthropometric body measurements (including weight, height and BMI) are commonly used to measure and track growth over time in children (infants, children, adolescents). Unlike adulthood, there are substantial periods of growth and development in childhood. As a result, it becomes even more important to not make judgments or decisions based on one measurement in time with children but rather consider measurements over a period of time (Dieticians of Canada and Canadian Paediatric Society, 2014). Keep in mind that health comes in all sizes and shapes (OSF Healthcare System, 2023).

Height, weight, BMI and other body measurements are considered in the context of growth charts which are percentile curves in reference or relative to children of the same age and sex (Dieticians of Canada and Canadian Paediatric Society, 2014). In this chapter, you are introduced to percentiles for children aged 2 to 19 years of age. In Canada, these are based on the World Health Organization.

Boys’ individual charts (based on sex assigned at birth):

Girls’ individual charts (based on sex assigned at birth):

Interpretations

See Table 2 for cut-off points for percentiles from the Dieticians of Canada and Canadian Paediatric Society (2014). Keep in mind that this table provides a simple understanding and in fact a full understanding of these cut-off points is much more complex. These are commonly used in primary care. When using these, additional training is suggested. Please see Dietitians of Canada for more information about training and additional interpretations.

In terms of how to read percentiles: an example is if a child’s BMI is 80th percentile, that means that the child’s BMI is more than 80% of children the same age and sex.

Table 2: Cut-off points

Growth status and indicator 2 to 5 years of age percentile 5 to 19 years of age percentile
Underweight

Weight-for-age

<3rd <3rd
Severely underweight

Weight-for-age

<0.1st <0.1st
Stunted

Height-for-age

<3rd <3rd
Severely stunted

Height-for-age

<0.1st <0.1st
Wasted

BMI-for-age

<3rd <3rd
Severely wasted

BMI-for-age

<0.1st <0.1st
Overweight

BMI-for-age

>97th >85th
Obese

BMI-for-age

>99.9th >97th
Severely obese

BMI-for-age

n/a >99.9th

 

Priorities of Care

Unexpected downward or sharp upward trends should be closely evaluated. Keep in mind that a trend is a general direction/change over a period of time and multiple measurements. For example, if a client shows a decrease in weight over multiple primary healthcare visits, this is something that should draw your attention. You may begin with a discussion about whether they have noticed the weight loss and whether there are any factors that may be contributing to this finding. You will want to continue to monitor whether this in fact is a trend that is of concern or whether it is just temporary.

References

Dieticians of Canada and Canadian Paediatric Society (2014). A health professional’s guide for using the WHO growth charts for Canada. Childhood percentiles

OSF Healthcare System (2023). Taking the confusion out of reading a growth chart. https://www.osfhealthcare.org/blog/taking-the-confusion-out-of-reading-a-growth-chart/