Global health authorities have formally recognised a distinct and long-overlooked form of diabetes that predominantly strikes young, slim individuals. The condition, now officially named type 5 diabetes, was first documented nearly 70 years ago but is only now receiving widespread clinical attention.
From 'Type J' to Global Recognition: A Seven-Decade Journey
The story of this diabetes variant began in 1955 in Jamaica, where Dr Philip Hugh-Jones treated 13 patients with diabetic symptoms that did not fit the profiles of type 1 or type 2. He provisionally labelled it 'type J,' but the term faded from use. Decades later, in the 1980s, the World Health Organization categorised it as 'malnutrition-related diabetes mellitus,' only to remove that classification in 1999 due to insufficient evidence.
Now, the International Diabetes Federation has granted it a definitive identity: type 5 diabetes. This milestone follows renewed scientific interest, particularly from a landmark study published earlier this year in The Lancet Diabetes & Endocrinology.
Who is at Risk and How Does it Differ?
Unlike type 2 diabetes, which is strongly linked to obesity and lifestyle, type 5 diabetes typically affects slim teenagers and young adults in low- and middle-income countries. Experts estimate that as many as 25 million people worldwide could be living with this condition, many unaware or misdiagnosed with type 1 diabetes.
While specific figures for the UK and US are not yet established, experts suggest that refugees, migrants, and individuals with a history of malnutrition or eating disorders may be at elevated risk. The American Diabetes Association has not yet formally added it to its classifications.
The physiological mechanism is distinct. Patients with type 5 diabetes can produce insulin and are not resistant to it, but chronic malnourishment has led to an underdeveloped pancreas that cannot manufacture enough. Consequently, standard insulin therapy is often ineffective.
Symptoms, Diagnosis, and a New Treatment Path
Symptoms mirror those of type 1 diabetes, including increased thirst, frequent urination, fatigue, and slow-healing wounds. These signs also overlap with classic malnutrition indicators like weight loss and persistent hunger. Patients are typically underweight, with a body mass index (BMI) below 18.5.
The recent Young-Onset Diabetes in Sub-Saharan Africa (YODA) study was pivotal. Researchers analysing nearly 900 young adults diagnosed with type 1 diabetes in Africa found that roughly two-thirds lacked the autoimmune markers characteristic of type 1. They also still produced small, measurable amounts of insulin, setting them apart from both major types.
This has spurred a shift in treatment thinking. Doctors are now investigating the use of a high-protein, nutrient-rich diet—emphasising zinc, B vitamins, and magnesium—to help patients gain healthy weight and stabilise blood sugar. Low, cautious doses of insulin may supplement this approach.
A coalition of 50 international researchers has since called for urgent action, stating in the Lancet Global Health that "misdiagnosis and underdiagnosis are likely to have negatively impacted the clinical care and lives of millions." They urge global bodies to promote more research into this phenotype, which likely affects the quality and length of life for a vast, vulnerable population.
