For decades, doctors treating young, very thin patients in rural India, sub-Saharan Africa, and parts of Southeast Asia faced a puzzle. These patients had high blood sugar. They had low insulin. But they did not fit Type 1 diabetes — because they never went into ketoacidosis (a dangerous acidic crisis that happens when there is almost no insulin). And they certainly did not fit Type 2 — because they were not overweight or insulin-resistant.
Doctors gave them wrong treatments. Some were put on high-dose insulin meant for Type 1 patients — and nearly died from dangerously low blood sugar as a result. Others were given diabetes drugs designed for insulin-resistant Type 2 patients, which did nothing for them. And some simply died young, undiagnosed, in communities where neither healthcare access nor nutritional security was a given.
That puzzle now has a name: Type 5 Diabetes.
The Official Recognition
In January 2025, an international panel of diabetes experts met in India and unanimously voted to classify malnutrition-related diabetes as "Type 5 diabetes." This decision was later endorsed at the International Diabetes Federation (IDF) World Diabetes Congress held in Bangkok in April 2025, where IDF officially recognised this long-overlooked form of diabetes. The meeting was held in Vellore, at the Christian Medical College — one of India's most respected medical research institutions. The Vellore Declaration, signed by 39 researchers from multiple countries, formally proposed the name and classification. The IDF — the world's largest diabetes organisation — ratified it at their Bangkok Congress. This is as official as it gets in global medicine.
What Exactly Is Type 5 Diabetes?
| Feature | Type 1 | Type 2 | Type 5 |
|---|---|---|---|
| Primary Cause | Autoimmune — body attacks insulin-producing cells | Insulin resistance due to obesity, lifestyle | Malnutrition — poor pancreatic development |
| Insulin Production | Very low (autoimmune destruction) | Normal or high initially; reduced over time | Low (impaired beta-cell development) |
| Insulin Resistance | No | Yes — hallmark feature | No — insulin sensitivity is normal |
| Ketoacidosis Risk | High | Low | Very low — key distinguishing feature |
| Autoimmune Markers | Yes (islet antibodies) | No | No |
| Body Weight | Normal or low | Overweight/obese typical | Lean — BMI often below 18.5 |
| Typical Age of Onset | Children/young adults | Adults (increasingly younger) | Adolescents and young adults |
| Primary Geography | Global | Global (highest in wealthy nations) | South Asia, Sub-Saharan Africa, Southeast Asia |
This new diabetes classification, known as severe insulin-deficient diabetes (SIDD), is characterised by high insulin deficiency levels and fluctuating blood glucose levels. Researchers believe it starts with poor nutrition over time, which can affect how the pancreas develops and how well it works later in life.
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How Malnutrition Causes Diabetes — The Biology
Type 5 diabetes results from prolonged undernutrition, particularly during early childhood and adolescence. Poor maternal nutrition, frequent infections, and chronic food insecurity can impair the development of the pancreas.
When a child grows up malnourished — not getting enough protein, essential micronutrients, or sufficient calories — their pancreas does not develop properly. Specifically, the beta cells that produce insulin are fewer in number and less functional than they should be. This is not an autoimmune attack on the pancreas. It is a developmental failure caused by poverty.
By the time the person reaches adolescence or early adulthood, their pancreas simply cannot produce enough insulin to keep blood sugar stable. The result: diabetes. But because the mechanism is completely different from Type 1 or Type 2, standard treatments fail.
How Many People Are Affected?
Type 5 diabetes is estimated to affect 20 to 25 million people worldwide, mainly in Asia and Africa. That is comparable to the number of people with tuberculosis globally. It is nearly as common as HIV/AIDS. Yet until 2025, it had no official name, no diagnostic guidelines, and no standardised treatment protocol.
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India is particularly significant in this picture. Christian Medical College in Vellore led much of the research that forced global recognition. South India, parts of Central India, and nutritionally deprived rural populations are among the highest-burden regions.
Why Was This Ignored for 70 Years?
Type 5 diabetes was first described in 1955 in Jamaica by British physician Philip Hugh-Jones. He noticed 13 patients who had diabetes-like symptoms but didn't fit Type 1 or Type 2 — and called them "Type J" for Jamaica. The name didn't stick.
The WHO recognised malnutrition-related diabetes briefly in the 1980s, but removed the classification in 1999 due to a lack of evidence and ongoing controversy about whether undernutrition alone was sufficient to cause diabetes.
The real reason for 70 years of neglect is simpler and more uncomfortable: this is a disease of poor people in poor countries. Research funding, clinical trials, pharmaceutical investment — all of it has flowed toward diseases that affect wealthy patients in wealthy markets. Malnutrition-related diabetes in a rural Indian or Kenyan teenager was never a commercial opportunity.
The Treatment Challenge
People with Type 5 diabetes are insulin deficient, but not insulin resistant. Many may be able to manage their diabetes with oral medication rather than with injections of insulin.
This is critically important. In resource-limited settings, oral medications are far more affordable and accessible than injectable insulin. The wrong treatment — giving high-dose insulin to a Type 5 patient — can cause dangerous hypoglycemia (dangerously low blood sugar), especially when the patient is food-insecure and may not be able to eat enough to counterbalance the insulin.
Current treatment principles include:
- Nutritional support to correct long-term undernutrition
- Oral diabetes medications to stimulate insulin secretion
- Low-dose insulin therapy only where appropriate and carefully managed
- Addressing food insecurity at the community level
What Happens Next — The IDF Working Group
Following the IDF recognition came the announcement of a new IDF Type 5 Diabetes Working Group, chaired by Dr. Meredith Hawkins of the Albert Einstein College of Medicine and co-chaired by Dr. Nihal Thomas of Christian Medical College in India.
The Working Group's mandate:
- Establish formal diagnostic criteria so doctors can distinguish Type 5 from Types 1 and 2
- Create a global research registry to collect patient data
- Develop training modules for healthcare professionals, particularly in low- and middle-income countries
- Advocate for WHO recognition — which would trigger government health policy changes worldwide
How Type 5 Is Diagnosed (Emerging Criteria)
- Age of onset: Typically under 30 years
- BMI: Below 18.5 kg/m²
- History of chronic undernutrition in childhood
- High blood sugar with insulin deficiency
- No autoimmune markers (negative for islet antibodies)
- No or very low risk of ketoacidosis
- Absence of insulin resistance
The Bottom Line
Type 5 diabetes is a real condition, officially recognised, affecting tens of millions of people — and India is at its epicentre. The medical community now knows this is not a variant of Types 1 or 2. It is its own disease with its own cause, its own biology, and its own required treatment.
The next step is getting it into medical textbooks, diagnostic guidelines, and clinical practice — particularly in primary care settings in South Asia and Africa where the burden is greatest. That work has begun. The name is now official. The clock, finally, is running.
