Researchers Say There Are 5 Different ‘Clusters’ of Diabetes Types

Until now, diabetes was classified into two main types, type 1 and type 2. Type 1, generally diagnosed in childhood, required insulin treatments, due to the pancreas not making enough insulin of its own. Type 2 was believed to be more lifestyle-related and was caused by the body producing enough insulin but having trouble delivering it to individual cells. There were other types as well, such as LADA (latent autoimmune diabetes in adults) and MODY (Maturity Onset Diabetes of the Young), but there were still variations not described by these categories. Not to mention the fact that over 90 percent of diabetes patients were categorized as type 2, despite the many differences between individual cases.

So a team of scientists at Lund University Diabetes Centre in Sweden and the Institute for Molecular Medicine in Finland set to work studying 14,775 blood samples from people with diabetes, looking for differences in their conditions. The results are a whole new way to categorize diabetes cases into five “clusters.”

Photo: Adobe Stock/Africa Studio
Photo: Adobe Stock/Africa Studio

Each of these clusters is genetically distinct from the others, and each has different characteristics and a different risk level for certain complications. Read about each individual type below:

cluster 1: Severe Autoimmune Diabetes (SAID)

This type of diabetes is basically what everyone thinks of as classical type 1. It becomes apparent before adulthood in people who may otherwise seem healthy. An immune disease attacks the beta cells of the pancreas, leaving the body unable to produce insulin. Among those people studied, only about six and a half percent had this type of diabetes.

Photo: Adobe Stock/Anetta
Photo: Adobe Stock/Anetta

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cluster 2: Severe Insulin-Deficient Diabetes (SIDD)

Similarly to cluster 1, people in cluster 2 are usually young and healthy. They, too, struggle to make insulin, but it is not the immune system that causes this incapacity. Rather, a defect in their beta cells seems to be the issue. About 17.5 percent of people suffer from this type of diabetes.

Photo: Adobe Stock/ugreen
Photo: Adobe Stock/ugreen

cluster 3: Severe Insulin-Resistant Diabetes (SIRD)

This cluster of people is generally overweight, contributing to insulin-resistance. Their bodies make insulin but, over time, use it less and less efficiently. Over 15 percent of people are believed to have this type of diabetes.

cluster 4: Mild Obesity-Related Diabetes (MOD)

This group of people is less overweight than group 3, yet their metabolisms are similar to those in group 3. Their insulin-resistance and diabetes diagnoses may come as a surprise. Roughly 21.6 percent of people studied had this type of diabetes.

Photo: Adobe Stock/Fotos 593
Photo: Adobe Stock/Fotos 593

cluster 5: Mild Age-Related Diabetes (MARD)

This type of diabetes is milder and age-related. It doesn’t appear until the later years of a patient’s life, but it often doesn’t require as much medication as other types of diabetes. Nearly 40 percent of diabetes cases fall into this category.

Photo: Adobe Stock/Syda Productions
Photo: Adobe Stock/Syda Productions

The researchers believe their findings could lead to better, more specialized treatment for people with different types of diabetes. For example, cluster 2 had the highest risk of blindness, but cluster 3 was most prone to kidney disease. Screenings for these issues, therefore, are more important in these clusters than in others.

Professor Leif Groop, a researcher involved in the study, suggests that the three more severe forms of diabetes should be treated more aggressively than the other two, and that cluster 2, which would have been classified as type 2 before the change, should actually be treated more like type 1.

He says:

“This is extremely important, we’re taking a real step towards precision medicine. In the ideal scenario, this is applied at diagnosis and we target treatment better.”

This regrouping of diabetes types could also help reduce the stigma surrounding type 2 diabetes. Many people believe type 2 diabetes comes from bad habits, but that is not always the case. The restructuring of the diagnosis system will likely lend itself to a better understanding of how nuanced and complex diabetes can be.

The team also believes they may come across more distinct types of diabetes in the future, as they continue to study more people in other countries. This could further aid researchers in developing specialized treatments and prevention methods for the different categories.

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