Growth charts, BMI charts, z-scores and WHO versus CDC. Knowing which growth chart to use can be confusing. In this episode, host Dr. Sam Manger and guest Dr. Kristie Bell deep dive into what we should be using to guide our growth assessments with kids and how we can start to recognise and discuss unhealthy weight trends early.
Dr. Kristie Bell is a clinical Dietitian with over 24 years of experience working with children and families. With a PhD in nutrition from the University of Queensland, Dr. Bell’s research has focused on the impact of nutrition on growth and health outcomes for children with complex care needs. She is currently the Director of Dietetics and foods Services at the QCHhS where she leads a team of dietetics and dietetic assistants to lead life changing care for people and young people.
Growth charts, BMI charts, z-scores and WHO versus CDC. Knowing which growth chart to use can be confusing. In this episode, host Dr. Sam Manger and guest Dr. Kristie Bell deep dive into what we should be using to guide our growth assessments with kids and how we can start to recognise and discuss unhealthy weight trends early.
Dr. Kristie Bell is a clinical Dietitian with over 24 years of experience working with children and families. With a PhD in nutrition from the University of Queensland, Dr. Bell’s research has focused on the impact of nutrition on growth and health outcomes for children with complex care needs. She is currently the Director of Dietetics and foods Services at the QCHhS where she leads a team of dietetics and dietetic assistants to lead life changing care for people and young people.
Health and Wellbeing Queensland acknowledges the Yaggera and Turrbal people, the traditional custodians on the lands on which this podcast was recorded and the traditional custodians on the lands of Borders on which you are listening. We pay our respects to the Aboriginal and Torres Strait Islander elders, past and present, for they hold the memories of the traditions, cultures and aspirations of Australia's First Nations.
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Speaker: Junk food advertising to children is actually really effective and children are really vulnerable and susceptible to that advertising. We have evidence that shows that it influences children's food choices, and it influences what they ask their parents to buy and what they ultimately eat.
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Sam: Welcome to the Clinicians Guide to Healthy Kids, a podcast series for health professionals brought to you by Health and Wellbeing Queensland's Clinician’s Hub. I'm your host Dr Sam Manger and in this series, we'll be diving deep into the topics that matter most in childhood weight management. We'll be talking to QLD experts across a variety of topics, including sleep, disordered eating and higher weight children, prevention and healthy growth with healthy diets. Let's get started!
Today we're going to start at the beginning by discussing what tools we need to clearly see if there is a problem and to do this, we have Kristie Bell joining us.
Dr Kristie Bell is a clinical Dietitian with over 24 years experience working with children and families. With a PhD in nutrition from the University of Queensland, Dr Bell's research has focused on the impact of nutrition on growth and health outcomes for children with complex care needs. She is currently the Director of Dietetics and Food Services at Children's Health Queensland Hospital and Health Service, where she leads a team of Dietitians and nutrition assistants to lead life-changing care for children and young people. So, thank you so much for joining us today, Kristie.
Kristie: Thanks so much for that intro, Sam.
Sam: Now please tell us a little bit about yourself and obviously you've got quite an extensive career and experience in this area, so what’s your ‘why’, why do you love working in this area?
Kristie: Thanks, Sam. Well, as you said, I'm a clinical dietician and I've been doing that for over 2 decades and working with children and families, I became a dietician because I love food! I love cooking, I always have since I was a child myself. But I've also always been interested in health and in how the way that we fuel our bodies can really influence our health and our wellbeing. And I'm really interested in learning more about that. And it was my interest in learning that prompted me to do a PhD and more research in the area, and I began working then in Paediatrics in 2000 and have continued ever since.
I just love working with children and families and helping them to navigate health messages, to put dietary strategies into practice to help them achieve their health goals. And now I am really fortunate to lead a fantastic team of Dieticians who share this passion as well.
Sam: Hmm, sounds very rewarding. So what do you see; let's start right at the beginning, as the biggest causes of unhealthy weight gain in childhood.
Kristie: Such a big question, that one is Sam! And I think when talking about unhealthy weights, we do always have to remember there are two ends of the spectrum. There is the underweight end, where children can have difficulty gaining enough weight and maintaining their weight. But we're talking about today the other end of the spectrum, where children have gained weight too rapidly and have reached an unhealthy high weight and an unhealthy high weight is mainly caused by an energy imbalance where too much energy is taken in through food and drink and not enough energy is expended through physical activity.
But there's many contributing factors to excess weight gain, such as individual genetics, a range of influences from families, communities, and the broader society. It's not simply about what you eat, but what you eat is really important.
Sam: Yeah, and it’s interesting to me when you look and you're the expert here, so of course, correct me where I'm wrong, but it's interesting we look at whilst it is an energy expenditure differential, it’s doesn't have to be a huge difference over time. It can be actually a surprising small increase, you know, 10 or 20% increase in calories, which doesn't look like a lot, but just accumulates over time that can lead to these things. So the, I suppose, the stigma or the idea that people are piling on loads of food onto their plate in order to get overweight is not biologically accurate. The set points can change insidiously over time and it can, as I say, be insidious and sneak.
Kristie: That's exactly right, Sam. And we know that excess weight gain long-term is actually due to really small differences or a really small energy imbalance. It can be as small as a couple of biscuits a day effectively, when in terms of food, but it's all about offsetting that with activity and the balance, as we said between energy intake and movement, or energy expenditure.
Sam: And you mentioned there also around the cultural and social aspects. So let's talk about that because the social determinants of health are enormously important and we've got to think about the environment with which we exist in. So what about our environment; how does this affect weight?
Kristie: Yeah, the environment's got an enormous impact on our weight gain and in fact, the environment is so influential that it's been termed ‘obesogenic’, where it can promote obesity by influencing the amount and the type of foods eaten and the amount of physical activity or movement that we undertake. And so, by environment I mean home environment, but also the community environment, and more broadly, our social environment. So there's lots of layers. By home environment, what I mean is that we know that children whose parents live with obesity are more likely to have a higher body weight themselves, and this is thought to be due to both inherited genes, but also to the family environment where children's eating and activity patterns are heavily influenced by their parents eating and activity patterns as well.
And another example of the home environment is Australians are spending more hours at work, which leaves less time for food preparation. So as a result, we tend to eat out more. We tend to rely on pre-prepared convenience foods more and these tend to be higher energy density. So there are lots of things in the home environment that can influence our weight gain.
In the community as well. So where we live really will influence what we eat, how we move and how much we move. There's food availability and food costs, so types of foods that are available nearby, nearby to home and school, for example, will influence what we eat. So fast foods; if there's lots of fast-food outlets nearby, we're more likely to choose those to eat, and we know that fast foods are tasty, they tend to be more processed, they’re more energy dense, and they're readily available. They're quick and they're relatively inexpensive.
And for other areas there might be poor access to fresh fruit and vegetables that can be highly dependent on where you live. If you live in a regional or rural or remote area, fresh fruit and vegetables may not be as readily available as they are in urban areas, and they may be more expensive, which makes it harder to incorporate those into our daily intake.
Sam: It's challenging, isn't it? Because we have this evolutionary mismatch where we evolved in an environment whereby there was a calorie deficit environment, you know, as I'm talking 250,000 years ago, over the last sort of period of time and now we exist in a very different world in the last 50 years, 40 years, and this obesogenic environment, as you say, has been produced, cultivated, slowly brought on where we have abundant calories of generally lower nutrient value, but of course, there is lots of good nutrients out there still and it’s hard for a human brain to sort of co-exist/live in that environment in a way that can manage all of those stimuli.
And you mentioned there around the culture having a big role and of course, advertising of certain products, especially to children and adolescents, which are obviously the target, often the target of these advertising can be, can add another layer on top of, as you say, the busyness of our lives and the general sort of disorientation around it.
Kristie: Yes, well done Sam, and we know that marketing and advertising unhealthy foods and/or junk food advertising to children is actually really effective, and children are really vulnerable and susceptible to that advertising. We have evidence that shows that it influences children's food choices, it influences what they ask their parents to buy and what they ultimately eat.
Sam: It certainly gives us a role as our duty of care as health professionals to consider not just the individual care that we deliver, which is obviously crucially important, but our role as health professionals in the culture and the setting and the environment as well, to advocate, even to campaign or lobby around areas to change some of these social determinants as best we can on behalf of our patients.
Now when we think about the actual impact of a child living with higher body weight, let's talk about that because that is also not just individual. There are obviously flow and biopsychosocial effects there as well.
Kristie - Yeah, absolutely. Having a significantly higher body weight for a long period of time can adversely affect a child's health and their wellbeing on multiple levels again. So in the short term, there's physical problems that you might expect associated, so that can include, you know, sleep apnoea, breathlessness on exertion, reduced exercise tolerance, metabolic consequences, cardiovascular risk factors, and so on. Children who are living with obesity are also at increased risk of gastrointestinal, musculoskeletal, orthopedic complications. There are lots of complications there.
But in addition to those, children can also experience discrimination and bullying and teasing by their peers, which can really impact on their social, emotional wellbeing as well.
Sam: And there are many concerns about that and we're specifically talking about growth and weight. The concern is obviously that bullying and ostracism, you know, within a potential society just further spirals that out of control, you know, makes people feel more shame and then that drives them more to certain behaviours that then may further drive. So, we're trying to interject. Interrupt that cycle as best we can for people's holistic care.
We'll be back after this short message
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Speaker: Unhealthy weight is one of our greatest public health challenges. Two in three Queensland adults and one in four children live with overweight or obesity. We need to shift the dial. That's why Health and Wellbeing Queensland has created Clinicians Hub for you, our clinical workforce. Clinicians Hub is a digital ecosystem of initiatives, resources and tools, including this podcast series, for multidisciplinary health professionals to support best practice prevention, identification, treatment and management of overweight or obesity, and it offers a wide variety of clinical tools and training to help you transform health for children, adults and families. Find out how Clinicians Hub can help you at www.hw.qld.gov.au/hub
Sam: And now back to the show.
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Sam: Now, if children are under-fives, we are talking about those young ones now and they're not yet at school, and they have a higher weight, are they likely to just to, you know, grow out of it? I’m talking about growth assessments now so I'm going to move our conversation over in that direction.
Kristie: Another really good question, Sam. It's actually a really tricky question that one. We know there's a longitudinal study In Australia at the moment, the longitudinal study of Australian children, it's a major national study that's following the development of 10,000 children and their families from all parts of Australia and this large study has found that some children who are overweight at a young age, so children who in the preschool years; four- to five-year-olds I'm talking about now, that they did return to a healthy body weight by the time they were eight or nine years of age.
So, some children do actually grow out of it. The study found that the four to seven-year age group may be a really crucial time for targeting prevention strategies for that reason. But we also know that children and adolescents with obesity are estimated to be 5 times as likely as those who are of a healthy weight to become an adult living with overweight and obesity as well. So, it was really important that at that young age that we do start some early intervention and prevention strategies.
Sam: And so therein lies the importance of what, the bulk of what we're talking about today, which is growth assessments because we want to be able to identify as early as possible, if there are some trends there that we need to support, and potentially change, and then also monitor on an ongoing basis so that we know, as you said, whether this is the trajectory is just returning as it were or something we need to look into further. So, let's start with some real basics here; what equipment do we need to complete growth assessments?
Kristie: Yeah, great. So, we know growth is a really important indicator of health and wellbeing in children. And the good news is to assess it, it's pretty simple; straightforward. As far as equipment goes, all you need is some scales that are calibrated that will measure to 100 grams, preferably, and that you have a nice flat surface to put them on, not carpet and not bumpy, so some nice tiles or lino or concrete is completely fine and then you need a way of measuring height, so a stadiometer. Now they can be really inexpensive or they can be really expensive. I think they range from under $100 to about $2000 plus, but you don't need anything expensive. It just needs to be attached to the wall, accurate and have a headboard. And then you might want a flexible measuring tape as well. So, you'll need that for measuring head circumference in small children or potentially waste circumference if that's appropriate as well. And then of course you need to be able to access some growth charts.
Sam: And so with the growth charts there, there's the World Health Organization growth chart, there's the CDC growth chart. So which one should Australian healthcare professionals use for children over 2?
Kristie: Yeah, good question, Sam. So firstly, in Australia for children under two, so infants and toddlers under two years age the National Health and Medical Research Council has recommended that we use the WHO growth chart for that age group. However, for children and young people over 2, so 2 to 20 years, the recommendation from the NHMRC is to use either the CDC or the WHO chart. The most important factor is that children and adolescents are consistently monitored on the same chart overtime and not across different charts. And this is because growth charts are not intended to be diagnostic, but they are intended to contribute to the overall clinical impression of the child being measured and generally irrespective of the chart that's used, if a child is growing normally, growth will approximately follow one of the lines on the chart.
Sam: Great. So we often talk about Body Mass Index, or BMI, and that's obviously got its pros and cons. But is BMI an accurate way to assess healthy growth in children?
Kristie: So BMI is an estimate I guess. So the term growth I guess refers to height gains and also to weight gains and these are best assessed using weight-for-age or height-for-age growth charts. BMI is a measure of body proportion, so it is how we assess body weight with respect to height. It's not a measure of adiposity, but we do know that higher BMI's are associated with higher body fat stores. So we do use it as an indicator of adiposity.
Sam: And in in children in particular, in adolescents?
Kristie: Yeah, we know that increased BMI is not always associated with increased body fat. It doesn't take into account differences in the amount of fat or lean tissue that an individual has, nor does it provide any indication of the distribution of body fat within the individual. So, and that's particularly true for children and adolescents, where height and body composition are continually changing throughout childhood as they grow. So for these reasons, BMI is a highly useful tool, but it's certainly not a diagnostic tool. And it needs to be considered in the context of the child's overall presentation.
Sam: And is the range different then? Because we often talk in adults about 20 to 25, but you often see kids will be quite a different BMI but still be healthy, growing healthy.
Kristie: So for children and teens, a healthy BMI range is age dependent and sex dependent. So we do need to use growth charts for BMI and the cut off for what is considered the healthy weight range changes based on age and sex. So the cut off will vary, yes and we certainly cannot use the same cut offs that we use for adults.
Sam: And how often do you recommend we do measure weight and height?
Kristie: Well, that's such a good question, and it really depends on the purpose of the measurement. Because growth is such an important indicator of overall health and wellbeing, primary care is the perfect location for regular weight and height assessments. So ideally anytime a child is attending a primary care physician would be an ideal time to measure their growth routine monitoring is important.
What's important is not what each individual measurement is, but what the overall picture is for the child and how their weight and growth are changing overtime. So, this will allow you to identify for child's weight and height is increasing as expected. That is, if it's following a growth curve or if it's diverging from the curve either through too rapid weight gain or the other end of the spectrum where weight gain is inadequate. So when growth deviates from the expected growth curve, this is what warrants further investigation into why this is occurring and if any support is needed.
Sam: So, as you said, that continuum matters, that weight trends mean regular routine weights have been taken and recorded and they've been viewed over a continuum of time rather than just see. Obviously there are extremes in isolation which should warrant further investigation, but typically we're watching and seeing how things go. When do you worry? You mentioned If it goes too high or too low, what are some instructions and guidance we can give listeners and clinicians around that.
Kristie: So if a child's weight and height are in proportion and their Body Mass Index is growing along a curve between say, the 5th and the 85th percentile, there is absolutely no cause for concern. If a child's weight shoots up from say, the 50th percentile or their BMI shoots up from the 50th percentile and crosses two of the major percentile lines, so then it goes above the 85th percentile. That would be a suggestion that they are gaining weight too rapidly or at an unhealthy rate and that we should then look into what's going on for that child and that family, and what might be causing that.
Equally, if it's going in the other direction, we'd also be concerned. Another area of concern might be if their BMI is above the 85th percentile, or actually in particular if it's above the 95th percentile, and consistently above the 95th percentile, then we might also want to look into that as well. A single measurement may not be a big cause for concern, but if it's consistently above that, then there might be reason to find out what's actually going on.
Sam: And what about waist circumference? Is that relevant? Is it evidence based? Do you often use it in your practice and clinic?
Kristie: Look, waist circumference and waist height ratio are being used with increasing frequency. It's being used because it's simple and non-invasive and it's used in adult settings a lot to screen for increased cardiovascular risk. But for children and adolescents, the relationships not as clear, and there's actually no universal recommendations about the use of weight circumference for assessment of weight status in children. And international guidelines actually don't recommend measuring it to identify overweight or obesity for children, because of the lack of data regarding its effectiveness.
However, it can be used as part of an overall assessment to assist in forming your clinical picture and looking at where the child's weight distribution lives. And it has been used in children as young as six years old to assist in identifying cardiovascular risk. And if you're doing that, you'd be wanting to look at a waist height ratio equal to less than half, so less than 0.5, and that can be useful in predicting cardiovascular risk.
Sam: OK, great. Now feedback tells us that many health professionals understand how to complete a height or weight for a growth assessment, but they're not sure what to do when they get those results. So what would you say to this.
Kristie: So once they've done the assessment, once they've looked at the changes over time and how that child's growth has been tracking, then start the conversation with the family about that, and about other things that might be going on. Do some further investigations. Potentially you might want to consider family history, blood pressure, blood sugar levels and so on. But also ask the family if they're open to having a conversation about it, because families, can be difficult for some families to have a conversation, particularly if a child has come from being bullied or having some bullying or teasing occurring they might be quite sensitive and parents can sometimes have difficulty accepting that discussion. So, be very non-judgmental and empathetic in having the discussion with the family.
Sam: And one of the other concerns that some health professionals may have is that some of these conversations, especially when we talk about people or children with a higher weight, that it can be very challenging and confronting, and the family may disengage with them as a as a clinician. So they they're...we want to maintain good rapport with our patients, we want to have a good therapeutic relationship with our patient. And sometimes the fear is that by raising things that are very uncomfortable and confronting, we could put that at jeopardy. So how do you try and navigate the potential sensitive conversations there, so that we remember that we're on the same page, we're all looking for the same thing.
Kristie: I think you've raised it there yourself, Sam, quite perfectly; having that rapport to start with is really important. It might not be what you want to bring up the first time you meet a family, and it's important to have that good relationship with them before you raise a topic that's really sensitive like this. As I said, you're not going to base your assessment on a single measurement anyway, you want some...want to know what's occurring over time that child and that family, so start gently. But even before that, when you're measuring their height and weight, explain what you're doing, explain why you're doing it, that it's primary healthcare; it’s standard practice, it's about overall health assessment. And have the discussion with them all along the way about what the different cut offs mean, but also the context. So be open and be really empathetic. That's really important and not judgmental. And avoid any language that's discriminatory or potentially stigmatizing as well.
It's a bit different when you're talking to adolescents. I think when you're talking to adolescents, you need to engage them and really treat them as being responsible for the choices that they make. And let's face it, adolescents are out there, they're out there buying take away, buying soft drinks. When they're with their mates, they need to be... have some ownership of the of the decisions that are being made as well.
Sam: Yeah, that makes sense, so really build in that autonomy either from a parental level or growing adolescent level and respecting that, and making that clear from the beginning that this is an open conversation that we're here to, to work out what works for their wellbeing and to take it from there
Kristie: Absolutely. And if they're not ready for it then, then leave it for next time!
Sam: Yeah, well, that's a good thing about being Health Professionals, we're always there for them whenever they want to come back. So thank you so much Kristie for your time and expertise and experience today. It was very useful and look forward to talking to you again one day.
Kristie: Thanks so much, Sam, it's a pleasure.
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Sam: Today we’ve been talking to Dr Kristie Bell from the Queensland Children’s Hospital. For more information on today's topics visit the Health and Wellbeing website on www.hw.qld.gov.au