S4: Growth Chart and Their Uses

Question 1

Describe obesity and malnutrition across the globe

Answer 1

• In the UK we don’t tend to see children suffering from extreme underweight malnutrition, but what we do see are children who are obese. Even children who are obese can be said to be malnourished and have poor health and poor growth. This is the first generation where children will die before their parents as obesity becomes the biggest public health problem in the UK.
• Afghanistan and Yemen have the highest percentage of children under 5 who are underweight.
• The USA used to have the tallest population but now is 9th, this is because being fed a lot in childhood and being big tends to lead to children who are taller.
  However children in the USA have become so big they are malnourished and this has led to being shorter.

Question 2

Why do we monitor the growth of individuals in clinical practice?

Answer 2

• To assess their overall health and nutrition.
• To diagnose diseases that present as poor growth.
• Allows to monitor disease and how the child is responding to treatment.
  There is no longer a universal child growth screening programme, babies are weighed at birth, then in the first weeks of life and maybe in the first year. After that age there is no routine weighing.

Question 3

How do we monitor growth?

Answer 3

We monitor the growth of three things:
- Weight.
- Height (length if under 2 years but not very accurate as they have to be measured upright and be still).
- Head circumference (tells us about brain growth).
It is important these measurements are accurate and correct, there are therefore guidelines in the measurement of growth to ensure it is consistent.
For example taking of shoes when measuring heights of children with a stadiometer, measuring head circumference from the where it is widest.
Once we have the measurements for a child we plot them on a growth chart.
A growth chart displays the normal range of measurements for children of all ages. It is important to remember that normal is a range. One child’s weight may be at the lower end of normal while the other is at the high end of normal. As a child’s age changes the range of normal also changes. The range is given as centiles that go from 0.4th centile to the 99.6th centile. (centiles are percentage).

Question 4

How do we define normal growth (what factors affect it)?

Answer 4

• Normal growth is affected by ethnicity, we know that south Asian populations are smaller and thinner (lower muscle mass), whereas western Caucasians tend to be larger and taller. This is normal because it is due to genetics.
• Social class also affects growth and this is likely due to nutritional in origin, but this is not normal as a child potential growth has been altered.
• The growth chart ranges of normal are based on optimal growth taken from measuring the growth of many breastfed babies over lots of different countries over 15yrs.

Question 5

Example of child’s growth:
Sheraz, aged 26 weeks, born at term weighing 3.4kg.
Weight = 7.6kg.
Length = 66cm.
Head circumference = 42cm.
What are his results and how would you explain them to his parents?

Answer 5

Results: His growth is within the range of normal, but his weight is a centile lower than when he was born. He went from 50th centile when born to now 25th centile. His weight is now 25th percentile length 25th percentile and head is 25th percentile so he is in proportion. A drop of one centile is not abnormal and he is in proportion, so his growth is okay.
Explanation to parents:
“If we lined up 100 healthy boys of exactly the same age in order of size, the smallest would have a weight around the bottom line (of the growth chart) and the heaviest around the top line. They are all healthy as we are all different shapes and sizes” “There would be about 75 boys heavier than Sheraz and about 25 lighter than him. His weight is on the same line as birth and matches his height and head size.”

Question 6

Describe factors affecting growth

Answer 6

• Nutrition is the main influence of growth perinatally (immediately before and after birth), prenatally therefore most important factor is the placental nutrition and hence placental function (if you are a mother who is healthy and doesn’t smoke, you will have a healthy placenta and a big child). Obese women will have small babies as it affects their placenta nutrition
• Genetics become increasingly important as we get older (past first year) e.g. if both parents short unlikely you will be very tall.
• Hormones also get more important as we get older e.g. GH and thyroid hormones
• The time a person hits puberty can cause deviations from your line on the chart, for example if you start puberty slightly later it may look as if you a crossing down percentiles. But when you start puberty you will move back up.
• Any chronic disease can influence growth.
• Delay in puberty is more likely in males than females, precocious puberty is more common in girls that boys.

Question 7

When during life is height velocity highest?

Answer 7

Height velocity (speed at which height is gained) is highest in early infancy and puberty!
- On height velocity chart, we can see that rate of growth is highest in the first year of life (babies double in size after one year)! For the rest of childhood the rate is slow, this is slowest around primary school age.
The rate of growth then shoots up at puberty, then once puberty ends it falls all the way down.

Question 8

Describe common problems seen with growth

Answer 8

• Faltering growth (used to be called “failure to thrive”). This is a term used in young children whose weight is crossing down the centiles, we take notice if someone crosses 2 or more centiles.
• Short stature. Term used to describe a short child (over age of 1) who is not meeting their height potential (not growing at rate they could grow based on their genetics).
• Underweight. Term used for thin older children who have a BMI less than the 2nd centile (BMI centile) for age and gender.
• Overweight. Term used to describe a child who has a BMI above the 91st centile for age and gender.
• Obesity. Term used to describe a child who has a BMI above the 98th centile for age and gender.

Question 9

Describe BMI (body mass index)

Answer 9

• BMI is a simple measure of growth, it is simply a weight for height measure, in other words is the individual correct weight for their height. The taller a person is, the more they should weigh.
  However in children the BMI reference ranges are different and they are also age and gender dependent.
• In the same way we have centile range charts for weight, height and head circumference in children we also have centile range charts for the BMI of children. This is because it allows us to adjust for age.
  As children get heavier they also get taller, but it is to do with the proportion we are interested in.
• If an infant eats a lot, they will put on weight and their bones will grow so they will put on weight and grow in proportion.If however they eat a high fat/sugar diet, they will gain weight and grow, but they will gain weight out of proportion to their height. Therefore they will increase in BMI and their weight will be out of proportion to their height.
• BMI doesn’t discriminate the amount of adiposity an individual has, it is just measuring weight. Therefore BMI is affected by other factors like muscle mass.
  So afro-caribean indivudals have higher BMI not necessarily because they are more fat, but because they have a higher % muscle mass.