Is it time for a new way to characterize diabetes?

It used to be that if a child were diagnosed with diabetes, it was type 1. In fact, type 1 diabetes is also known as ‘juvenile diabetes’ and type 2 as ‘adult-onset diabetes’. Thanks to a multitude of factors, that’s no longer necessarily the case. Because the different types of diabetes may require different treatments, it’s important for doctors to know what they’re dealing with. Unfortunately, according to Katharina Warncke and her colleagues from Technische Universität München, the distinction between type 1 and type 2 diabetes may not be as meaningful as we think.

In type 1 diabetes, a patient’s own immune system destroys the insulin-producing islet cells within his pancreas. In contrast, patients with type 2 diabetes can make insulin, they just don’t react to it properly. Thus, one way to distinguish type 1 from type 2 diabetes is to look for diabetes-associated antibodies. 

The researchers recruited patients in the Diabetes Mellitus Incidence (DiMelli) Cohort Registry. Subjects included 630 young Bavarians under the age of twenty who had been diagnosed with any kind of diabetes within the past six months. Blood samples and a detailed history was taken for each participant. 

The scientists were interested in whether kids with multiple islet autoantibodies showed a different phenotype than kids with one or no autoantibodies (who might really have early onset type 2 diabetes rather than type 1 diabetes). 

Nearly all the subjects (522) had two or more diabetes-specific antibodies. Subjects with one or more of these antibodies were clinically similar to type 1 diabetes whereas patients with zero diabetes-associated antibodies were more similar to type 2 diabetes. No surprises there. However, there was a continuum of values rather than a clear distinction. In other words, classifying people as having either type 1 or type 2 diabetes did not tell the full story. Patients could not be cleanly separated into one group or the other.

Author Anette-Gabriele Ziegler explains:

In order to be able to introduce the right steps in treatment and to offer patients accurate information about their disease, it is essential to refine the criteria for differentiating and diagnosing the different forms of diabetes. Further studies are now required to shed light on the long-term development of the phenotypes, the distribution of different types of diabetes and the way in which their features present themselves in adult patients.

Warncke K, Krasmann M, Puff R, Dunstheimer D, Ziegler AG, & Beyerlein A (2013). Does Diabetes Appear in Distinct Phenotypes in Young People? Results of the Diabetes Mellitus Incidence Cohort Registry (DiMelli). PloS one, 8 (9) PMID: 24023937.