In the early 1950s, British physician Philip Hugh-Jones was flummoxed by 13 patients who showed up at the diabetes clinic he ran near Kingston, Jamaica.
At the time, researchers broadly recognized two kinds of diabetes, known today as Type 1 and Type 2. Hugh-Jones himself coined those terms in a study of hundreds of patients published in 1955.
Most of his patients fell into those two buckets, but that group of 13 people didn't fit into either category, says Michael Boyne, an endocrinologist at the University of the West Indies, where Hugh-Jones did his research.
"They were relatively young, thin and kind of undernourished looking," says Boyne.
Normally, that would point to Type 1 diabetes, where individuals are unable to make their own insulin and can become underweight.
But these 13 patients never experienced a common symptom of Type 1 — ketoacidosis. That occurs when the body runs out of insulin and starts burning fat for fuel, which can lead the blood to become dangerously acidic.
"Even though they were thin, they never developed keto[acidosis]," says Boyne, seemingly ruling out Type 1 diabetes. But they didn't seem to be Type 2 diabetics either, who tend to be overweight.
"So he said, 'Huh, these guys are different. They don't fit Type 1 or 2,'" says Boyne. "So he called them Type J." That's "J" for Jamaica.
The name didn't stick. Subsequent names didn't stick either, despite cases of this unusual form of diabetes continuing to surface, especially in areas afflicted with malnutrition. Now, 70 years later, an international team of researchers is trying to formalize a new name — Type 5 diabetes.
"The time is ripe" to recognize this disease that could impact as many as 25 million people," says Dr. Meredith Hawkins, a diabetes researcher at Albert Einstein College of Medicine.
In April, the International Diabetes Federation adopted the new name. Now, in a perspective published in The Lancet Global Health, Hawkins and an international team of researchers are urging other entities, including the World Health Organization, to get on board too.
"It is important, from a scientific perspective, to give it a name," says Nihal Thomas, an endocrinologist at the Christian Medical College in Vellore, India, who is part of the effort. "And patients will benefit a lot," he said, since some are getting treatment that can be deadly.
The dangers of not having a name
After Hugh-Jones published his 1955 paper, researchers around the globe started noticing similar cases that didn't fit Type 1 or Type 2.
"It had a variety of names over time, but they were all generally describing the same thing," says Boyne. "And in Southeast Asia, India and Africa, they really noticed a strong connection with malnutrition in early life."
Hawkins herself first saw this unusual form of diabetes while working in Uganda in the early 2000s.
"A lot of very impoverished patients that were coming in from rural areas, very thin and malnourished, very high blood sugars," she says. They'd exhibit classic symptoms of diabetes, including frequent urination, excessive thirst or hunger, and even nerve damage.
To most clinicians, including Hawkins at the time, such patients seem like classic Type 1 cases. The standard treatment would be to send them home with a lot of insulin. But she and her colleagues soon learned that this approach could be lethal.
"Basically, in many cases, committing them to a death sentence from low blood sugar," if they didn't have enough food to eat at home, she says. Insulin is a hormone that helps shuttle sugar from the blood into cells, where it can be used for energy. Too much insulin, coupled with too little food, can result in dangerously low blood sugar, she says.
Seeing such cases of "young people who had died from low blood sugar because they weren't being appropriately treated really motivated our research," says Hawkins.
What makes Type 5 diabetes different
Since then, she and other researchers have learned that physiologically, people with Type 5 diabetes look different from those with Type 1 or 2. Those differences seem to be shaped by malnutrition.
"These individuals have generally had malnutrition from the time they were in utero," says Hawkins. "They're malnourished as toddlers, as children, as adolescents and as adults. These are the ones that don't catch up. They just stay very thin, and that makes them different than other forms of diabetes."
One key difference is the pancreas, where insulin gets produced. Evidence suggests that malnutrition in early development harms the ability of the pancreas to pump out insulin.
"Their pancreas is crap," says Boyne. "It's not as bad as Type 1, but it's really crappy."
That leaves people with Type 5 diabetes in a weird spot. They can produce some insulin and their cells respond to it (unlike people with Type 2 diabetes, whose cells are often resistant to insulin), but they can't make quite enough to normally regulate their blood sugar.
"We felt very strongly that if this was a separate entity, it needed separate treatment," says Hawkins. Figuring out the best treatment will take more research, she says, something she hopes the new name can galvanize.
Not everyone in the diabetes research community is convinced that Type 5 diabetes is a distinct entity or that it deserves a new name.
"Formal classification risks codifying what may be a spectrum of poorly characterized Type 2 diabetes rather than a discrete entity," says Anoop Misra, an endocrinologist at the Centre of Nutrition & Metabolic Research in New Delhi. He says the existing data isn't enough to definitively establish a distinct form of diabetes.
The International Diabetes Federation disagrees, though, and launched a working group aimed at developing better diagnostic criteria and treatment guidelines for Type 5 diabetes. (It chose the name Type 5 as uncontested territory, since there are ongoing efforts to label other forms of diabetes as Types 3 and 4.) Advocates hope recognition by other health authorities, including the World Health Organization, could help that effort, at a time when cases are poised to rise in some parts of the globe.
Food crises in Gaza, Sudan, the Democratic Republic of Congo, Nigeria and Yemen could be setting up a generation for increased risk of Type 5 diabetes, says Boyne.
"It's really heart-rending," he says. "This is something that's preventable — it's preventable by food."
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