Surely this is wrong - NHS BMI calculator?

[WonderingStars]

DD been having some health issues and has recently had a bout of viruses. I decided to weigh her first thing and was worried to see that she’s fallen to the 4th percentile. It may be the viruses alone are responsible but I emailed the school nurse and will discuss this with her consultant next week.

Onto my AIBU... the NHS BMI calculator says a child is only underweight if they are at, or below, the 2nd percentile. Children are only considered overweight if they are above the 91st (I think) percentile. Yet every other chart I’ve checked (e.g. the CDC have a simlilar calculator to the NHS) says below the 5th percentile is underweight and above the 85th is overweight.

According to the NHS then, I don’t need to worry about DDs weight loss, and parents with children between the 86th and 90th percentiles don’t need to be concerned either. Of course I am left wondering why the NHS criteria are different and a cynical part of me thinks it’s resources driving policy rather than good practice.

So AIBU to think this, or are there sound reasons for the 2nd and 91st percentiles being the NHS boundaries for concern instead of the 4th and 86th?

Ds in on the 0 centile for weight.

I think for most it just falls into the natural variety of body size for the age/height hence it only being the extremes which may be cause for concern unless there is a sudden extreme change

There will always be children who are naturally at either end of the spectrum. However this doesn't mean that weight LOSS isn't concerning.

I don't think bmi is applicable to children

Dd 15 is on the 3rd centile ds 14 is on the 0 centile, both under a paed gastroenterologist as they’re coeliacs

Gastro is aware and unconcerned as they’re just built like dh long and thin not like 5ft rubinesque me

So long as they keep growing and gaining weight in proportion it’s not really a problem

As others have said, there’s always someone at the top and someone at the bottom

Ds has just had the flu, I’m not going to check his weight as I can see he’s dropped, experience tells me he will turn into a food hound soon and put some weight back on and it’s Christmas soon so he’s bound to eat lots of naughty stuff

As long as they are following the same line I don't think it matters what centile they are. Weight loss is a concern.

Measuring obesity using centiles is astonishingly foolish, I'm genuinely surprised that they are given such weigh in medicine these days.

Centiles only tell you where your/your DC's weight sits relative to others

Is assumes that the 50th centile is somehow the 'ideal' weight when in reality, as society gets fatter and fatter, the 50th centile will shift upwards into more and more worrying ground.

We need to measure weight objectively, not relatively.

I agree with previous poster re: centiles. What is the CDC? I am presuming you mean the US based health organisation? I wouldn't directly compare guidelines on health from two different countries (ie NHS and CDC) as those guidelines may not actually bear much relevance to each other as they will be based on different research, and the resulting guidelines will have ethnographically different audiences.

Just had a quick read and the NHS chart is based on different data, to the CDC, so that could account for it.

I would look at the child's growth curve. Dropping by two centile lines or more is generally cause for concern. As is being more than two centiles' difference in height and weight.

However, my dd is below the 0.4th for weight and on the 9th for height. She's absolutely fine, just a bean pole. She's always been that way. However, if she had started out on the 50th for weight, that would be concerning.

I think you should worry about any weight loss in a growing child that isn't intentional (for an overweight child). Don't bother with centiles etc, children are meant to gain weight, not lose it.

@430West I know, it seems stupid to me. Children are getting bigger and bigger.

Do you mean her BMI (weight / height^2) or just her weight?

For children there is a different bmi chart which looks at height, weight and age.

It's not weight so much as weight loss, which is the marker for concern. You need to weigh her in a few days and then again and see if it is dropping.

All my babies have been on or near 0 or 2nd percentile. That's just them. They aren't underweight or malnourished.

It really doesn't matter whether they are on the 2nd or the 4th, or the 91st. What matters is if they were following the 25th (for example) but have dropped to the 2nd or 4th, or anything far from their usual line.....or gained a huge amount (unless they were poorly and underweight to begin with). My daughter is (and always has been) around the 1st percentile for height and 14th for weight, so she's slightly heavy for her height, but is tiny stature. Perfectly healthy.

Yes, as others have said. The centile is not as relevant as weight loss or not increasing weight as expected.

My Ds lost weight last year because he wasn’t eating enough at school. I was worried, but I kept a record of his weight and fed him up at breakfast time!
He regained the weight quickly over Christmas, and continued on his centile.
If he wasn’t gaining weight pretty quickly I would’ve gone to the gp.

DS wavered between 2nd and 6th centimetres for years; I think he's now about 8th, so I no longer keep an eye on it. When he was at his thinnest, he wouldn't have looked out of place if it had been the 1950s, but next to today's heavier children , he looked thin.

Why are you not worried? She’s losing weight so probably not getting nutrients, suffering from the bugs etc I can’t see the relevance of percentiles here.

It must be wrong, my 4yo dd has always been around 95-98th centile for weight but she's also on the 98th for height, she's very slim.

I thought the height/weight had to be similar, ie a child on the 98th for weight but 20th for height would be overweight.

Hereabouts (England), CDC is the Child Development Centre at our local General Hospital.

Thank you, I understand now that there are a variety of charts relating to different data sets, which are not necessarily comparable and the NHS advice re BMI is fine.

I have added the info from her wall chart to her red book and I can now see that her height, for most of her first year, was above the 91st percentile, by the time she was 4.5 she was on the 75th and now she is on the 50th.

The same with her weight, for most of her first year she was on the 91st, by 2.5 she was still above the 75th, (I then have no info until 8.5 yrs when she has dropped to the 25th) and now her weight is a whisker above the 9th.

By the way, I am now using the Royal College of Pediatrics and Child Health charts and these place her BMI a whisker above the 2nd percentile (although using these charts BMI is not a cause for referral until it falls below 0.4).

So I feel reassured that her BMI in and of itself is not a cause for concern, however I am unsure about the fall she's taken through the percentiles from a baby until now.

It seems like a big drop to me, not only through the percentiles but also with the divergence between her height and her weight - in your experience is this still normal as it's happened over a long time period or do children generally track along, or fairly close to, one percentile throughout their childhood?

Just to add that at 2.5 yrs her BMI was just below the 75th percentile, so very different to her current BMI of nearly 2. I know that toddlers tend to have a greater weight to height ratio, but the chart seems to account for that - she is not like some children described above, who have always had a low BMI.

Does anyone have a similar experience?

My professional opinion is that bmi is useful but not massively important.
For example, I am muscular and have an above average bmi but only 20% fat. My weight is muscle so my bmi is misleading.

Op ignoring centiles and bmi has your daughter lost actual weight? If she has you need to take her to a doctor.

Kaytee

I don’t know, what led me to weigh her the other day is her appetite seems poor despite being over the viral illness.

After 2.5 I stopped recording her weight, but a year ago she wanted to know all our weights - so I know that in the last 11 months she’s put on 1.1kg but I’ve no idea if this is normal or not.

The WHO say dropping percentiles after the age of 3 is not normal, so I will discuss this at her appointment next week. I’m just looking for reassurance really...

Obviously I will weigh her weekly to see what’s happening over the next few weeks too.