The International Diabetes Federation (IDF) has officially recognized a fifth type of diabetes.
Type 5 diabetes is classified as a distinct form of diabetes in young, lean individuals (BMI <body‑mass index <18.5 kg/m², age <30 years) with a history of undernutrition. This differs from other types of diabetes, which include
- Type 1 (autoimmune, inability of the pancreas to produce insulin)
- Type 2 (insulin resistance, often due to obesity, lifestyle, diet or genetic factors)
- Gestational (caused by hormonal changes during pregnancy)
Categorizing type 5 diabetes has been professionally discussed since 1995. According to The Lancet Global Health, “In 1985, the World Health Organization (WHO) formally classified type 5 diabetes as malnutrition-related diabetes, but subsequently removed the classification in 1999 over a disagreement as to whether undernutrition was a sufficient risk factor to cause this type of diabetes.
Type 5 diabetes was first documented in The Lancet in 1955 by P. Hugh-Jones, who named it J-type diabetes after observing young, underweight people in Jamaica. These people were insulin-resistant but were not prone to ketoacidosis, a potentially life-threatening event where the body breaks down fat rather than glucose for energy, causing dangerous acidity in the blood.
Regardless of the type, untreated diabetes may affect eye health, including diabetic retinopathy, macular edema, cataracts and glaucoma.
This research highlights how nutritional status during early development can shape metabolic disease risk later in life, pointing to the need for more tailored diagnostic criteria and treatment approaches in global health settings with persistent undernutrition.
