BMI of 13.6 - should this be a concern?
Discussion
Not myself I would stress!
I don't know how well such measures relate to children?
My son is 7 and frankly has always been a skinny as a stick. We are taking part in a longitudinal study of lots of developmental indices, and at the last visit, they took a measure of BMI. I was expecting him to be low, maybe 17-19, but was shocked when he was 13.6.
I'm not really TOO concerned, because he's happy, energetic (not that sporty, to be fair), but looks quite healthly (hair, skin, eyes) despite looking like a mating between a xylophone and a deckchair.
Does this need to be monitored or mentioned to his doctor?
I don't know how well such measures relate to children?
My son is 7 and frankly has always been a skinny as a stick. We are taking part in a longitudinal study of lots of developmental indices, and at the last visit, they took a measure of BMI. I was expecting him to be low, maybe 17-19, but was shocked when he was 13.6.
I'm not really TOO concerned, because he's happy, energetic (not that sporty, to be fair), but looks quite healthly (hair, skin, eyes) despite looking like a mating between a xylophone and a deckchair.
Does this need to be monitored or mentioned to his doctor?
wendyg said:
Not myself I would stress!
I don't know how well such measures relate to children?
My son is 7 and frankly has always been a skinny as a stick. We are taking part in a longitudinal study of lots of developmental indices, and at the last visit, they took a measure of BMI. I was expecting him to be low, maybe 17-19, but was shocked when he was 13.6.
I'm not really TOO concerned, because he's happy, energetic (not that sporty, to be fair), but looks quite healthly (hair, skin, eyes) despite looking like a mating between a xylophone and a deckchair.
Does this need to be monitored or mentioned to his doctor?
BMI for children is different than for adults. 13.6 puts him borderline normal/underweight. 17-19 would have him borderlline normal/at risk of obesity.I don't know how well such measures relate to children?
My son is 7 and frankly has always been a skinny as a stick. We are taking part in a longitudinal study of lots of developmental indices, and at the last visit, they took a measure of BMI. I was expecting him to be low, maybe 17-19, but was shocked when he was 13.6.
I'm not really TOO concerned, because he's happy, energetic (not that sporty, to be fair), but looks quite healthly (hair, skin, eyes) despite looking like a mating between a xylophone and a deckchair.
Does this need to be monitored or mentioned to his doctor?
If he is otherwise healthy I would say continue as is, but be looking for it to increase year on year.
BMI is a crap measure. It under-rates people who are short (such as kids or dwarves) and over-rates people who are tall. I am 6 feet tall and my brother is 5 ft 7. I have the higher BMI but he looks far more heavily built than me.
The ponderal index is better. Instead of the square of height (which the BMI uses) the ponderal index uses the cube of it, which is logical when you think about it, us being 3 dimensional and all. Keeping proportions constant, an increase in height has to be matched by the same proportionate increase in width AND in depth.
Imagine a cylinder of height h and radius r. Its volume is Pi r^2 h. If you increase each dimension by 10% its volume (in terms of the original r and h) is Pi (1.1r)^2 (1.1h) = 1.1^3 Pi r^2 h, which is not 21% more but 33.1% more, i.e. it's gone up by the cube of the proportionate increase in height.
Try telling that to GPs though, they're not going to listen. Just make your own mind up.
The ponderal index is better. Instead of the square of height (which the BMI uses) the ponderal index uses the cube of it, which is logical when you think about it, us being 3 dimensional and all. Keeping proportions constant, an increase in height has to be matched by the same proportionate increase in width AND in depth.
Imagine a cylinder of height h and radius r. Its volume is Pi r^2 h. If you increase each dimension by 10% its volume (in terms of the original r and h) is Pi (1.1r)^2 (1.1h) = 1.1^3 Pi r^2 h, which is not 21% more but 33.1% more, i.e. it's gone up by the cube of the proportionate increase in height.
Try telling that to GPs though, they're not going to listen. Just make your own mind up.
Never use BMI for children. It is only designed for fully grown adults and even then it has it's limitations.
As said above, plot the child's weight on an appropriate centile chart, you can download them if you can't find the red book. If the weight over 6 months drops down through the centiles then that can be a cause for concern.
If you think the child is unwell then see a doctor.
As said above, plot the child's weight on an appropriate centile chart, you can download them if you can't find the red book. If the weight over 6 months drops down through the centiles then that can be a cause for concern.
If you think the child is unwell then see a doctor.
You'd think someone would tell the NHS that BMI is a 'crap measure' and should never be used for children.
BMI healthy weight calculator
BMI healthy weight calculator
NHS said:
NHS healthy weight BMI (body mass index) calculates adult BMI and child BMI accurately, and provides advice and information on healthy weight management.
You can calculate BMI "accurately" for anyone of any age (if you can do basic maths). It is a "reliable" measure but it's "validity" is questionable.
The cut offs for "obese" etc are dubious at the best of times but have minimal validity when applied to children.
It is not the number that is relevant it is the trend. Hence why children are assessed according to growth charts. You can say that if a child's height to weight ratio (BMI) is crossing centiles then it indicates a problem, this is "valid" but the number in isolation has limited value.
IMHO
The cut offs for "obese" etc are dubious at the best of times but have minimal validity when applied to children.
It is not the number that is relevant it is the trend. Hence why children are assessed according to growth charts. You can say that if a child's height to weight ratio (BMI) is crossing centiles then it indicates a problem, this is "valid" but the number in isolation has limited value.
IMHO
Only thing that matters is is child happy, physically healthy and growing and developing at a reasonable rate?
Friend has a daughter with dwarfism - the kid's first years were full of 'failure to thrive' and stuff and even talking about feeding tubes at one point - because she weighed about half what an average 3 year old did, it hadn't occurred to anybody that she was actually on a perfect growth curve (adjusted for kids with dwarfism) and eats like a horse. Now 14, of very short stature and doing absolutely fine.
Friend has a daughter with dwarfism - the kid's first years were full of 'failure to thrive' and stuff and even talking about feeding tubes at one point - because she weighed about half what an average 3 year old did, it hadn't occurred to anybody that she was actually on a perfect growth curve (adjusted for kids with dwarfism) and eats like a horse. Now 14, of very short stature and doing absolutely fine.
wendyg said:
he's energetic (not that sporty, to be fair), but looks quite healthly (hair, skin, eyes) despite looking like a mating between a xylophone and a deckchair.
This describes me until I hit about 25 yrs of age. For a very long time I was anything up to 25% below 'ideal' weight for my age, but was perfectly healthy. The advantage is that when even he does 'fill out' he still won't be a bloater... 
.stackmonkey said:
wendyg said:
he's energetic (not that sporty, to be fair), but looks quite healthly (hair, skin, eyes) despite looking like a mating between a xylophone and a deckchair.
This describes me until I hit about 25 yrs of age. For a very long time I was anything up to 25% below 'ideal' weight for my age, but was perfectly healthy. The advantage is that when even he does 'fill out' he still won't be a bloater... .Until the dreaded 40 hit. Then despite his activity levels staying much the same, he :ahem: filled out. When we've looked back further HIS dad did exactly the same at the same age.
Stevenj214 said:
NHS said:
NHS healthy weight BMI (body mass index) calculates adult BMI and child BMI accurately, and provides advice and information on healthy weight management.
But then you read, "calculates adult BMI and child BMI accurately", but "provides advice and information on healthy weight management".
It doesn't actually claim that BMI is accurate, only that the maths produces an accurate result which they call BMI. No s
t.And it only merely provides "advice", not fact, consultation, conclusivity etc.
In other words, they know BMI is BS government mass-hysteria spin for drones.
mattikake said:
That's a disgraceful statement!
But then you read, "calculates adult BMI and child BMI accurately", but "provides advice and information on healthy weight management".
It doesn't actually claim that BMI is accurate, only that the maths produces an accurate result which they call BMI. No st.
And it only merely provides "advice", not fact, consultation, conclusivity etc.
In other words, they know BMI is BS government mass-hysteria spin for drones.
But then you read, "calculates adult BMI and child BMI accurately", but "provides advice and information on healthy weight management".
It doesn't actually claim that BMI is accurate, only that the maths produces an accurate result which they call BMI. No s
t.And it only merely provides "advice", not fact, consultation, conclusivity etc.
In other words, they know BMI is BS government mass-hysteria spin for drones.
wendyg said:
stackmonkey said:
wendyg said:
he's energetic (not that sporty, to be fair), but looks quite healthly (hair, skin, eyes) despite looking like a mating between a xylophone and a deckchair.
This describes me until I hit about 25 yrs of age. For a very long time I was anything up to 25% below 'ideal' weight for my age, but was perfectly healthy. The advantage is that when even he does 'fill out' he still won't be a bloater... .Until the dreaded 40 hit. Then despite his activity levels staying much the same, he :ahem: filled out. When we've looked back further HIS dad did exactly the same at the same age.
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