We don’t yet know why type 1 diabetes develops. However a JDRF-supported project called The Environmental Determinants of Diabetes in the Young (TEDDY) is looking into the causes of the condition. There are a number of genes that are linked to type 1 development, but not everyone who has these genes will develop the condition, and so it seems likely that there are also ‘triggers’ in the environment that stimulate the development of type 1. TEDDY is a project which is tracking children at risk of type 1 until they’re 15 years old, the team will look at diet, illnesses, allergies and a host of other life experiences.
Using the TEDDY project data, Dr Andrea Steck and her team at the Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, explored the difference between two groups of children with type 1 who were diagnosed at different times. One group of children had already been identified as having genes that increased their type 1 risk, and had blood tests every three months for autoimmune activity as a way of identifying type 1 before symptoms developed. This group were compared to children diagnosed through symptoms of type 1 such as weight loss and excessive thirst. The researchers wanted to see if those diagnosed earlier by regular blood tests showed benefits such as producing insulin for longer than those children diagnosed later.
What did the researchers do?
Both groups of 43 children participated in long term follow up after diagnosis, including HbA1c tests – an average of blood glucose level over three months. The participants were also given mixed tolerance tests, a liquid meal taken with timed measurements of C-peptide (a protein produced alongside insulin, and which can act as a measure of insulin production inside the body) were carried out at one, three, six and 12 months after diagnosis, then every six months after.
What did they find?
The results showed that 58 per cent of TEDDY children, who were tracked as a result of their genetic risk, had no symptoms such as weight loss or increased thirst at diagnosis, and none had diabetic ketoacidosis (a dangerous complication that arises when the body begins to break down fat as an energy source, as a result of not being able to use glucose). Comparatively, 98 per cent of the later diagnosed children had diabetes symptoms and 14 per cent had diabetic ketoacidosis. At diagnosis, average HbA1c was lower in the TEDDY children (6.8 per cent, 51 mmol/mol) than later diagnosed children (10.5 per cent, 91 mmol/mol).
TEDDY children produced significantly more C-peptide, and therefore insulin, than the other group throughout the first year after diagnosis. Total insulin dose and HbA1c were lower throughout the first year post diagnosis for TEDDY children compared with other children.
What does this mean for people with type 1?
This study shows that the children who were involved in the TEDDY project were less likely to have diabetic ketoacidosis at diagnosis and had the chance to participate in trials which could prolong their own production of insulin for longer – an idea which may delay or help prevent type 1 complications with better control for a longer period of time.