'Everyone with low BMI will not get Type 5 diabetes.'
A recent news report caught the attention of the world -- Type 5 diabetes.
While Type 1 and Type 2 diabetes are well-known, what is this new entity?
Largely ignored and neglected, the International Diabetes Federation (IDF) World Diabetes Congress 2025 in Bangkok on April 7 highlighted this issue.
In a major move to tackle this form of diabetes, IDF President Professor Peter Schwarz announced a working group to study and develop diagnostic criteria for Type 5.
The working group is co-chaired by Dr Meredith Hawkins from the Albert Einstein College of Medicine in New York, and Dr Nihal Thomas, Senior Professor of Endocrinology at the Christian Medical College in Vellore.
Speaking to Rediff Senior Contributor Shobha John, Dr Nihal Thomas explained that Type 5 is mainly due to chronic undernutrition associated with low birth weight and continued during childhood, leading to impaired pancreatic development.
It was first seen in the 1950s in undernourished populations in Jamaica and subsequently across India, Pakistan and parts of sub-Saharan Africa.
It was included in the WHO classification in 1985 as 'malnutrition-related diabetes mellitus.
However, it was omitted in 1998 for lack of evidence of it being a definite form of diabetes.
It is now being given the attention it needs as diabetes has pervaded insidiously all over the world.
"Type 5 diabetes is sporadic presently, not endemic. Malnutrition should be tackled, but there are enough of other reasons which need its attention," explains Dr Thomas.
Recently, the IDF drew the world's attention to Type 5 diabetes. Is there also Type 3 and Type 4 diabetes?
Yes, there are various categories. Type 1 is auto-immune, insulin-deficient diabetes. It is largely present before 15 years, but older people can get it.
Type 1, if left untreated, can be dangerous in many patients as they could develop ketoacidosis.
Due to the total lack of insulin, the body uses existing fat in the body for energy and this can lead to the formation of ketoacids.
Patients may become ill as the Ph of blood may drop drastically.
Type 2 is generally found in adults over 35 years where insulin is produced, but does not work appropriately on the receptor. The person is generally overweight.
Type 3 C is pancreatic diabetes wherein there are structural problems in the pancreas with duct dilatation and calcification.
Type 3 is a secondary form of diabetes induced either by hormones, steroids, etc.
Type 4 in German medical literature is associated with pregnancy. Prof Peter Schwarz, who is of German origin, has labelled gestational diabetes as Type 4.
You are one of the leaders of the global task force formed to explore Type 5 diabetes. What are your findings so far?
There was a joint consensus meeting in January when the 'Vellore Declaration' was proclaimed, organised by Dr Felix Jebasingh of Vellore and me with 40 experts.
During the IDF meet in Bangkok, Type 5 diabetes was officially labelled and declared.
The task force of which I am a part of has certain targets for 2027, but work will go on for years.
The pathogenesis, epidemiology and public policy for it will be determined.
Research by you and your colleagues has shown that Type 5 is seen in people with an extremely low BMI of less than 18.5kg/m2. This would be seen in which categories of people?
For the last 30 years, many researchers have been working on malnutrition and low birth weight.
Dr C S Yajnik, director, Diabetes Unit, KEM Hospital Pune, and a member of the team which devised the Vellore declaration (January 2025) has been working on the Barker Hypothesis which states that if you are born with a low birth weight or have a condition which reduces blood circulation to the foetus, the risk of hypertension, obesity and diabetes is more in regions with good food security.
Therefore, low birth people here will increase fat and eventually become insulin resistant and get Type 2 diabetes and sooner in their 20s and 30s.
If there is undernutrition after birth, pancreatic development is inadequate and production of insulin lower and this can lead to malnutrition related diabetes.
However, this label is not enthusing for anyone, particularly patients. Therefore, a term such as Type 5 diabetes is apt.
It is largely rural in origin, in those with childhood malnutrition. Patients have lower body fat composition and are lean. They are insulin deficient but do not have ketoacidosis.
Even if insulin is halted for a few days, nothing critical may occur in Type 5 diabetics.
What are the symptoms of Type 5 diabetics?
They are lean, do not have ketoacidosis and do not have a visible structural disease of the pancreas.
However, we also need to look at shades of grey--among those with higher BMIs between 18.5-21.
So are sports people who may have low BMIs be at risk of Type 5 diabetes?
Everyone with a low BMI will not get Type 5 diabetes.
In which countries has Type 5 diabetes been detected?
They mainly affect people in low- and middle-income countries such as sub-Saharan countries (eg, Ethiopia, Uganda and Tanzania).
As Type 5 is related to malnutrition, can this be cured with proper dietary intake of proteins, fibre and essential micronutrients? If so, should there be state-funded programmes to reduce it?
We have found that even if the socio-economic condition of patients with Type 5 diabetes improves, their intake of proteins is habitually low.
It is not just glucose which is a stimulus for insulin production; even amino acids (which are the building blocks of proteins) are a stimulus for insulin production.
However, whether a higher protein diet could improve insulin production, will need to be ascertained.
Type 5 diabetes is sporadic presently, not endemic. Malnutrition should be tackled, but there are enough of other reasons which need its attention.
Also, can one be malnourished despite having a high BMI due to the intake of junk food, etc?
The word malnutrition can mean overnutrition or undernutrition. Type 5 is about undernutrition.
Does Type 5 start from infancy or in the womb itself? Can an undernourished mother have a baby with Type 5 diabetes or does the child have a proclivity for it later in life?
The evolution of Type 5 diabetes encompasses undernutrition in the womb along with undernutrition in childhood.
This has been found in studies on rats where pups which have been undernourished in the womb as well as after they were born have lower insulin production and a lower islet cell load.
If a child in undernourished in the womb but receives good nutrition later, he may not develop Type 5 diabetes, but could be prone for insulin resistance and Type 2 diabetes--this is the Barker Hypothesis.
Are people with Type 5 diabetes treated in the same way as Type 1 and Type 2 or does it require specialised treatment?
We have seen from data is that although Type 5 diabetes is insulin deficient, 50% could be managed by oral medications, as evidenced by a study done with my colleagues coordinated by Prof Meredith Hawkins and Riddhi Dasgupta.
They do not need insulin injections.
India is called the diabetes capital of the world, with over 74 million having this illness. What percentage of this number has Type 5 diabetes?
The number of diabetics in India varies depending on which study one is looking at.
IDF in 2021 had said there were 53 crore (530 million) diabetics internationally and this was predicted to go up to 130 crore (1.3 billion) by 2050. My estimate is that 5% of diabetics in India have Type 5 diabetes.
As you are going to study Type 5 in depth, do you have a sample group of people you will be studying?
We know parts of India, rural areas, where it is more prevalent, and we will be looking at these groups.
Our task force will also be working with countries where Type 5 is more prevalent in Asia, Africa and South America.
As diabetes has reached epidemic proportions in India, should the Centre start a national campaign to tackle it, beginning from primary school itself? Maybe a specific subject called Diet can be introduced to catch them young.
Yes, far more needs to be done to induce behavioural change.
Curricular redesigning for schools is required to encourage persistent physical activity, awareness about the impact of air pollution should be induced and strategies to implement higher protein intake should be implemented.
What is the reason for India having so many diabetics? Are we genetically predisposed to it or is it our diets with so many sweets to blame for it or simply a lack of awareness?
According to the Global Burden of Diseases study published in The Lancet in June 2023, there are 19 risk factors for Type 2 diabetes.
These include particulate matter PM 2.5 (particulate matter) and PM 10.0 which may enter the blood through the respiratory tract and penetrate the islet cells which produce insulin.
Other factors include lower physical activity, ambient particulate air pollution, household air pollution, smoking, second-hand smoke, low birth weight, diet low in fruits, fibre, vegetables and whole grains, diet high in red meat, processed meat and sweetened beverages, reduced sleep, increased stress, high alcohol usage, high BMI and very high ambient temperature.
India also has a huge number of pre-diabetics. Can this be reversed with regular exercise and diet?
Moderate exercise of at least 45 minutes per day, 4-5 days a week is essential. In 50% of people, the progression to overt diabetes could be prevented.
Feature Presentation: Ashish Narsale/Rediff.com
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