Impacts of physical activity in the early stages of type 1 diabetes
As research increasingly focuses on the early stages of type 1 diabetes, a presentation at the American Diabetes Association’s 83rd Scientific Sessions covered the emerging data on the potential of physical activity in children. Lisa Buckingham reports.
Kimber Simmons, Assistant Professor of Paediatrics at the Barbara Davis Centre for Diabetes, US, began with the US physical activity recommendations for children – for children three to five years old, physical activity is encouraged throughout the day; children and teens aged six to 17 need 60 minutes every day and most of this can be moderate-intensity aerobic activity. They also need to do muscle strengthening activity at least three days per week and bone-strengthening activity three days per week.
The health benefits of exercise in children and adolescents include improved cardiometabolic health, improved cognition and reduced risk of depression – what’s key to note is that if they exercise as children, they’re more likely to exercise as adults.
The same sort of effects apply for people with diabetes, such as reduced adiposity, lower risk of premature all-cause and cardiovascular mortality, as well as lower HbA1c and improved insulin sensitivity.
Are paediatric patients meeting activity guidelines? No, they’re not, said Professor Simmons. The goal is to increase the proportion of children and adolescents that do enough physical activity. The most recent data in the US show that only 23.6% of children aged six to 13 met the current guidelines in 2020-21, which is less than in 2016-17 when it was 25.9%. The target is 30.4%. The same applies for adolescents, she said – the figures are getting worse.
How active are children with type 1 diabetes? Professor Simmons highlighted a 2012 paper showing that children under seven with type 1 diabetes were less active overall and spent 16 minutes less in moderate-to-vigorous physical activity (MVPA) than age-matched control children. Overall physical activity per day and time in MVPA was significantly higher in boys. A more recent paper from 2019 found the same thing – children aged six to 18 with type 1 diabetes exercised less than healthy controls.
She highlighted interesting data from a 2023 paper that tracked physical activity in children at risk of type 1 diabetes from five to 18 years old. The drop-off in physical activity over the years is gradual and significant, and shows that we should be intervening earlier to maximise health benefits.
Impact of physical activity in the early stages of type 1 diabetes
There are many barriers to exercise for children with existing type 1 diabetes, but Professor Simmons’ focus for this presentation was on the early stages and new-onset type 1 diabetes and the emerging data in this area.
She drew attention to an infographic showing the stages of type 1 diabetes. More attention has recently been given to the early stages and a medication was recently approved to give before people have symptoms (stage 2) to try to delay onset and progression to stage 3. We get asked a lot, she said, whether there is anything that can be done after screening to intervene in the very early stages to stop it from happening at all and wouldn’t it be amazing if there was something more than immunotherapeutics that could help.
There is some data showing potential benefits of physical activity in the early stages and in new-onset type 1 diabetes and that it may slow progression to stage 3 in children. It may also extend remission time in children with new-onset diabetes.
What are the potential mechanisms for this? If we’re thinking about an immune response, said Professor Simmons, exercise can reduce insulin resistance by increasing glucose transporters and glucose uptake in skeletal muscles. It also reduces risk of respiratory diseases, which is not only associated with potential onset but also continued decreasing beta cell mass; it decreases visceral fat mass, which is a source of fat-derived cytokines; it switches the cytokine environment to anti-inflammatory; it decreases beta cell death by normalising glucose and lipid levels, and it preserves beta cell health by reducing endoplasmic-reticulum (ER) stress-induced apoptosis.
Next, she highlighted a study focusing on the honeymoon period in 125 children. Partial remission was defined as HbA1c < 7% and daily insulin requirements < 0.5 U/kg/24hr. They followed the participants every three months and recommended standard exercise guidance. At two years, they were given a questionnaire to see if they were adhering to the guidance and found that the participants who were more active had a lower HbA1c, but also maintained C-peptide production for longer. Forty four per cent of people who were active had partial remission at two years, so maybe we should talking more about this at onset, she said.
The next two studies came out of work done through The Environmental Determinants of Diabetes in the Young (TEDDY), an international consortium following children at high risk from a family member or high HLA risk gene and are measured for islet autoantibodies (IA). They were fitted with a physical activity (PA) monitor at age five and this was worn for seven days every year until age 10 unless IA positive, in which case they wore it until age 15.
The first study done with this data was done on 209 children who had multiple islet autoantibodies. They’d had at least one oral glucose tolerance test (OGTT) and at least one physical activity measurement. Linear mixed modelling was used to examine the relationship between physical activity and OGTT results, controlling for country, gender, HLA DR3/4, age, sex-standardised body mass index and accelerometer wear time. It found that higher MVPA was associated with improved glucose and C-peptide for those children. The stronger association with longer multiple IA+ duration might suggest MVPA could play a role in delaying progression in very high-risk children. And also that high-risk children who maintain higher MVPA as they grow older may reduce age-related decreases in insulin resistance, reducing stress on the pancreatic beta cells.
The second study went on to ask whether or not physical activity impacts the development of islet autoimmunity or progression to type 1 diabetes. It was divided into three risk groups: children who were still IA- at the first PA measurement (group 1); those who had one IA at the PA measurement (group 2) and those with multiple IAs at the PA measurement (group 3).
For group 1, no association was found between MVPA and the risk of developing a single IA. In group 2, a marginally significant association was found between MVPA and the risk of progression from single to multiple IA. In group 3, it became more interesting, said Professor Simmons, because there was an association between MVPA and the progression from multiple IAs to type 1 diabetes.
In summary, it found that every 10-minute increase in daily MVPA was associated with an 8% reduced risk of progression to type 1 diabetes in children with multiple IAs. It also found that for children in that group who were glutamic acid decarboxylase (GADA)-positive at the initial seroconversion, a 10-minute increase in daily MVPA was associated with a 12% reduction in the risk of progression to type 1 diabetes. Professor Simmons listed the limitations of the study, such as not including dietary exposures, and it may not be generalisable to children with other genetic backgrounds as the children were mostly White European.
So we know that exercise is beneficial, she said, but how on earth do we get people to do physical activity if we know that it’s already declining by age 5? There is good advice from the health departments such as splitting up the 60 minutes of activity over the day by walking to school, playing on the monkey bars at school and walking the dog after school, but we still need to establish what’s going to be effective. There are initiatives aimed at working this out, such as Activate (a type 1 diabetes physical activity research study) at the University of Vermont, but they’re all focusing on older children, which doesn’t address the issue of declining activity levels in younger children.
We have a lot of work to do, she concluded, and a lack of data at this time. In the future, we need to identify and address barriers to physical activity in youth with all stages of type 1 diabetes.
To learn more about promoting physical activity for people with diabetes, enrol on the EASD e-Learning course ‘Lifestyle intervention’.
Any opinions expressed in this article are the responsibility of the EASD e-Learning Programme Director, Dr Eleanor D Kennedy.