Type 2 diabetes diagnosed before adulthood is fast becoming a problem in many countries, and one that, in Western countries at least, disproportionately affects children from ethnic minorities.
Julian Hamilton-Shield (University of Bristol and University Hospitals Bristol NHS Foundation Trust, UK) is an author on a study exploring type 2 diabetes in children younger than 17 years in the UK in 2015–2016. The team found markedly increased incidence rates in Asian and Black children, at 2.92 and 1.67 per 100,000 children per year, respectively, compared with just 0.44 per 100,000 children per year in White children. These findings are in line with ethnic disparities reported for other countries, such as the USA, and were not unexpected, since they also reflect type 2 diabetes incidence patterns in adults.
Likewise, Hamilton-Shield says the results fit with the pattern of obesity in children, which “is more prominent amongst children from certain ethnic minority groups, such as those of African, Afro-Caribbean, and South Asian heritage.”
Genes or environment?
A characteristic of ethnic minority families is that they often occupy a relatively low socioeconomic position, which is associated with poorer health and access to healthcare. But is this the only explanation for their increased propensity to develop type 2 diabetes?
Despite its strong association with lifestyle factors, Hamilton-Shield stresses that type 2 diabetes is fundamentally a genetic disorder, and therefore influenced by ethnic genetic variation. “There are many different genes involved,” he explains. “It’s a multigenic disorder: they accumulate to increase your risk of diabetes.”
One genetically determined trait is differences in body fat disposition, with Asian people in particular tending to store excess body fat primarily as visceral fat.
“And we know that visceral fat tends to be the dangerous fat,” says Hamilton-Shield. “It’s much more fluid, it’s much more active, and it’s much more liable to lead to insulin resistance and fatty liver and the things associated with so-called metabolic syndrome.”
This may have its roots in evolution, with the ability to store calories as central fat conferring an advantage in environments with prolonged periods of food shortage.
But Hamilton-Shield says: “We’re now talking about second- or third-generation children of people who migrated to the UK in the 50s perhaps, or the 40s, and those genes are all loaded towards being able to store visceral fat.”
Far from being advantageous, in today’s Western society, with cheap, easily available, high-calorie food, the ability to accumulate body fat represents a health hazard. Hamilton-Shield says evidence of this is also seen in the more affluent urban centers in countries like India, where its transformation into a place with readily available food has resulted in an incidence of type 2 diabetes in children and young people that “is actually quite high.”
In addition to genetic determinants of fat storage, genes influencing pancreatic development and function also likely contribute to the risk for type 2 diabetes.
“There’s some people who can be really quite heavy but have no evidence that they’ve got any abnormalities of glucose tolerance at all,” says Hamilton-Shield. “And that’s probably because they’re very lucky in that respect and they’ve got the genes that allow them to continue to produce lots of insulin regardless of how heavy they are.”
But people with genetic vulnerability to diabetes lack this advantage, so if they become obese their pancreas struggles to keep up with the increased demand for insulin.
“All these things combine to give you an increased risk of getting type 2 diabetes at any given weight,” says Hamilton-Shield.
And against this background of genetic vulnerability, “the trigger – the thing that actually sets things off – is the relentless increase in childhood obesity,” says Hamilton-Shield, describing it as “an accelerator effect” leading to type 2 diabetes appearing at ever younger ages.
How does ethnicity influence clinical management?
Hamilton-Shield highlights two areas where ethnicity has an important impact on a practical level in the clinic.
Normalization of type 2 diabetes
The first is not so much a direct effect of ethnicity but a consequence of coming from a family with a history of type 2 diabetes, which was the case for 81% of the children in the UK study.
He explains: “I think within families – including those of northern European descent – where type 2 diabetes has been a player for a long time within the family, there’s almost: well that’s what was going to happen anyway and we know lots of people have it in the family and I’m not that surprised.”
Then the challenge is to help children see that although their grandparents and parents may have type 2 diabetes, they developed it a lot later in life, with less time for complications to arise, whereas a child of 15 years will be living with the condition for the majority of their lifetime.
Hamilton-Shield stresses how poor long-term outcomes can be for children who develop type 2 diabetes so young – markedly worse than for children with type 1 diabetes. For example, the TODAY2 study, which published in 2019, followed up TODAY participants for an average of 7.5 years after they were diagnosed with type 2 diabetes during childhood, finding young people with, in the words of the lead investigator, “problems you’d expect from your grandparents.” There was a rapid accumulation of vascular risk factors and diabetes complications, even including a few incidences of myocardial infarction, end-stage kidney disease, and amputations. Pregnancy outcomes were poor, and five participants died, two as a direct consequence of vascular complications.
Hamilton-Shield cautions against relaying such dire statistics to children with type 2 diabetes, but stresses the need to get across the fact that type 2 diabetes is a serious condition.
He believes that by comparison with type 1 diabetes – a condition with a clearly defined treatment and obvious and immediate consequences for non-adherence – type 2 diabetes is “not perceived as being such a problem and we do probably need to change people’s attitudes to that.”
“I think we’re moving towards the idea – well, certainly we are in Bristol – that we need to actually make it abundantly clear to the young people we meet, and their families, that this is a serious condition that has really quite serious implications.”
But he adds that, unlike for type 1 diabetes, “most of the ways you can improve are with your own lifestyle, so basically changing your eating behavior, changing the amount you exercise, which puts a lot of onus on them which perhaps they don’t want to hear.”
This leads directly to the second way in which ethnicity affects clinical management, because families from ethnic minorities will struggle to follow diet and lifestyle advice that has been tailored to Northern European people.
“You do need to have culturally appropriate dietary changes,” says Hamilton-Shield. “There’s no point talking about things the family don’t eat at home – that’s not going to help at all – and so everyone’s moving […] towards more directed dietetic advice for the groups who you’re dealing with.”
Hamilton-Shield stresses that diet must be the mainstay of pediatric type 2 diabetes management, pointing to the success of the DiRECT trial, which showed that targeting 15 kg weight loss in adults using a very-low-calorie meal replacement plan led to type 2 diabetes remission for nearly half of the participants.
“And so I’m a very great believer in healthy changes and probably quite strict changes at least initially to try and elicit a 10% to 15% weight loss,” he says, adding that he sees no reason why the DiRECT approach should not be used in adolescents where needed.
Other lifestyle changes, such as increasing exercise, can also be deployed in support of diet, but again this has to be culturally appropriate. “For instance, you can’t tell young ladies from certain ethnic minorities to go to a gym, and be among lots of other people doing exercise all the time, because that may be culturally difficult for them.”
Working with children
Such considerations apply regardless of age, but Hamilton-Shield stresses that children, whatever their ethnicity, are a unique group, with their own age-specific requirements. So while there is much to learn from adult endocrinologists about ethnic differences in adult type 2 diabetes, “I do think we’re going to have to have our own skillset as well.”
He notes that adolescents “aren’t just young adults – they are a very different and a very complex group to deal with. They’re charming and lovely to deal with but sometimes they have slightly different attitudes to the old men talking to them across the desk – which is me!”
These specific requirements are reflected in the team of healthcare professionals assembled to support these children and their families, and the ways in which these experts interact.
“It’s an interesting one really, because traditionally the doctors have kind of run the type 1 diabetes [clinics, albeit] with huge assistance from our pediatric diabetes nurse specialists and our dietitians and our psychologists,” says Hamilton-Shield.
“But we could argue that when you look at my tier 3 obesity service, which manages really quite severe obesity, no one person really defines the treatment aims for our children. It’s a combination, and in my childhood obesity service we not only have doctors, dietitians, nurse specialists, psychologists, we also have a social worker. And our social worker is actually central to a lot of the work that we do.
“So I do think the dynamic is very different and type 2 diabetes probably lends itself much better to the real multidisciplinary team, where no one has the absolute say on what’s the best for any patient.”
He says: “There’ll always be a place for the doctor, maybe just to explain a condition a bit, prescribe a diabetes medication, and to lay down the ground rules of what you need to do and how often you need to come.”
But he adds that in his childhood obesity clinic, “what I think is only one of five or six people’s thoughts, and I think I’ve got the right idea maybe 15%, 10% of the time – if that – and other colleagues have much better insight into what’s going on in the family and how to elicit those behavior changes you need.”
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