What’s Type 5 diabetes that has been recognised after decades all about?

This type of diabetes is not new as it was first reported in Jamaica in 1955 as J-type diabetes. In 1985, the WHO classified the condition as “malnutrition-related diabetes mellitus” which was subsequently removed in 1999 for lack of evidence. Subsequently it was reported in many other countries, such as India, Sri Lanka, Bangladesh, Uganda, Ethiopia, Rwanda, and Korea, with a current estimate of 25 million people affected globally. Recent research has brought renewed attention to the impact of malnutrition on pancreatic development and insulin function, particularly in individuals with poor nutrition in childhood or early adulthood. This research has led to the re-classification of malnutrition-related diabetes as Type 5.

What is Type 5 diabetes?

Type 5 diabetes is a form of diabetes affecting lean and malnourished teenagers and young adults in low- and middle-income countries.

Dr Nihal Thomas, professor of endocrinology at Christian Medical College (CMC) Vellore and among the Type 5 working group members, says that this causes pancreatic beta cells to function abnormally, leading to insufficient production of insulin. In Type 2, the body resists insulin action despite producing it. “Due to the lack of formal recognition, this condition has been understudied and misdiagnosed,” he says.

This type of diabetes is not new as it was first reported in Jamaica in 1955 as J-type diabetes. In 1985, the WHO classified the condition as “malnutrition-related diabetes mellitus” which was subsequently removed in 1999, citing a lack of convincing evidence of causal link with malnutrition.

What are markers of Type 5 diabetes?

According to Prof Thomas, this unique form of diabetes, observed in Asian Indians, has no evidence of autoimmune or genetic causes. “Affected individuals have a significantly lower body-mass index (BMI) — of less than 18.5 kg/m2 — than those reported in previous Indian studies. Insulin secretion is severely reduced — much lower than typical Type 2 Diabetes and just above levels seen in Type 1 Diabetes. Unlike Type 2 diabetes, the liver’s production and release of glucose into the bloodstream is lower. Body scans reveal a substantially lower percentage of body fat compared to Type 2 diabetes cases. Additionally, dietary intake of proteins, fibre and essential micronutrients is significantly low,” Prof Thomas explains.

It all begins in the womb

Dr C S Yajnik, director, Diabetes Unit, KEM Hospital Pune, and a key member of the Type 5 Diabetes Working Group, details how malnutrition begins in the mother’s womb. “If a baby does not get the right amount of nutrition while growing in the womb, it can increase the risk of diabetes later in life. For a long time, many Indians were undernourished due to hard labour, colonisation and famines. But in the past 50 years, with rapid urban growth and development, overeating has also become a problem. When a baby is under or over nourished before birth and then gains too much weight later, it can lead to Type 2 diabetes. But if the baby stays undernourished both before and after birth, it can lead to this malnutrition-related diabetes, or as now christened, Type 5 diabetes,” he says.

What about treatment?

According to Dr Thomas, a high protein diet is important. Depending on the person’s low BMI and physical activity levels, an adequate amount of carbs and fats are needed to ensure weight gain. “Anti-diabetic medicine or insulin is considered based on the level of glucose and the therapeutic response on a case-by-case basis,” he says.

The working group will now define diagnostic criteria that apply to diverse populations and help devise treatment modules.