Type 2 Diabetes Now Outpaces Type 1 Among India’s Youth, Major Study Finds

A sweeping analysis of more than ten thousand young patients at one of India’s leading diabetes centres has revealed a striking shift in the landscape of early-onset diabetes: type 2 diabetes, long considered a disease of middle age, is now diagnosed more often than type 1 diabetes in people under 25. The retrospective study, published in BMC Endocrine Disorders, examined 10,449 individuals registered between 2010 and 2023 at a network of diabetes centres in South India, and its findings carry uncomfortable implications for a country already grappling with what researchers have called the diabetes capital of the world.

The numbers tell a clear story. Of the 10,449 individuals diagnosed with diabetes at or below the age of 25, 51.6 percent had type 2 diabetes, while 45.5 percent had type 1 diabetes. The remaining 2.8 percent fell into other categories, including maturity-onset diabetes of the young (MODY), gestational diabetes mellitus, and fibrocalculous pancreatic diabetes, a form of diabetes linked to chronic pancreatic disease that is seen with relative frequency in tropical regions. That type 2 diabetes accounts for the majority of youth-onset cases at a tertiary referral centre underscores how dramatically the traditional age boundaries of the disease have eroded.

The clinical profiles of the two main groups differed sharply. The average age at diagnosis was 21.1 years for those with type 2 diabetes, compared with just 13.5 years for those with type 1 diabetes. Classification was not arbitrary: type 1 diabetes was identified by a history of diabetic ketoacidosis, low C-peptide levels indicating minimal insulin production, and the need for insulin therapy from the moment of diagnosis. Type 2 diabetes, by contrast, was defined by the absence of ketosis, preserved C-peptide levels, and a sustained response to oral glucose-lowering drugs for at least two years. This rigorous phenotyping lends weight to the central conclusion that the two conditions, while sharing a name, follow very different trajectories when they strike early in life.

Perhaps most alarming is what the study found when it looked at long-term complications. Among patients who had lived with diabetes for 15 years or longer, retinopathy, the damage to the light-sensitive tissue at the back of the eye that remains a leading cause of blindness in working-age adults, affected 61.0 percent of those with type 1 diabetes and 53.9 percent of those with type 2 diabetes. Diabetic kidney disease, a progressive condition that can end in dialysis or transplantation, was present in 36.1 percent of the type 1 group and a remarkable 49.1 percent of the type 2 group. Neuropathy, the nerve damage that underlies foot ulcers and amputations, appeared in 29.7 percent of those with type 1 diabetes and fully half of those with type 2 diabetes.

These complication rates are not merely statistics; they represent a generation facing the most devastating consequences of diabetes decades earlier than previous cohorts. The authors attribute the heavy burden of microvascular disease, damage to the small blood vessels of the eyes, kidneys, and nerves, to suboptimal glycemic control across the youth-onset cohort. Prolonged exposure to elevated blood glucose is the principal driver of these complications, and the data suggest that young patients, whether they have type 1 or type 2 disease, are not achieving the tight metabolic control needed to protect their organs over a lifetime of disease.

The temporal trends add another layer of concern. Using joinpoint regression, a statistical technique that detects changes in trends over time, the researchers found a modest but statistically significant annual increase in the prevalence of diabetes diagnosed at age 25 or younger, with an annual percent change of 1.42. The rise was more pronounced for type 2 diabetes, which showed an annual percent change of 2.39. While the increase in type 1 diabetes has attracted global attention, particularly in terms of rising incidence in childhood, the steeper climb in youth-onset type 2 diabetes reflects the broader metabolic shifts sweeping through populations undergoing rapid nutritional and lifestyle transitions.

To understand what distinguishes young people who develop type 2 diabetes from those who develop type 1, the team turned to logistic regression, modelling the odds of each diagnosis against a battery of clinical and behavioural variables. Older age at diagnosis, higher body mass index, a strong parental history of diabetes, and physical inactivity emerged as key predictors of type 2 diabetes relative to type 1. The pattern is biologically coherent: excess adiposity and sedentary behaviour drive insulin resistance, while inherited genetic susceptibility, reflected in parental diabetes, accelerates the failure of insulin-producing cells to compensate. In a population with a well-documented genetic predisposition to insulin resistance, the combination of urbanising lifestyles and early-life weight gain appears to be pulling the onset of type 2 diabetes into adolescence and early adulthood.

The study was conducted at a tertiary care diabetes centre in Chennai, anchored by the Madras Diabetes Research Foundation, an Indian Council of Medical Research collaborating centre of excellence, and Dr. Mohan’s Diabetes Specialities Centre, recognised by the International Diabetes Federation as a centre of excellence in diabetes care. As a referral institution, the centre may see a disproportionate share of complex cases, and the authors note that the findings reflect the population served by this network rather than the general Indian population. Nevertheless, the sheer scale of the registry, built on electronic medical records spanning more than a decade, offers an unusually detailed window into youth-onset diabetes in a country where such data remain scarce.

The research was approved by the institutional ethics committee and conducted in accordance with the Helsinki Declaration and Indian Council of Medical Research ethical guidelines, with informed consent waived because de-identified retrospective records were used. The work forms part of a growing effort, including India’s Young Diabetes Registry, to systematically characterise diabetes in the young, a group whose clinical needs differ substantially from those of older patients and who face the longest possible exposure to the disease and its complications.

For clinicians and public health officials, the message is unambiguous. Type 2 diabetes in the young is no longer a curiosity; at this centre it is the dominant form of diabetes diagnosed before the age of 25, and it arrives with a complication burden that rivals or exceeds that of type 1 diabetes. The authors call for earlier diagnosis and better glycemic control for both types, a goal that demands earlier screening of at-risk young people, aggressive management of blood glucose from the outset, and structural interventions to address the obesity and inactivity driving the rise of youth-onset type 2 diabetes. As India’s young population continues to grow, the study suggests that the window to prevent a lifetime of diabetic complications is closing earlier than anyone would like.

Subject of Research: Trends and complications of youth-onset type 1 and type 2 diabetes in India

Article Title: Trends, clinical characteristics, and complications of individuals with type 1 and type 2 diabetes diagnosed below 25 years of age as seen at a tertiary care diabetes centre in India

Article References: Reji, S., Umasankari, G., Venkatesan, U., Ganesan, S., Jebarani, S., Pradeepa, R., Anjana, R. M., Unnikrishnan, R., Mohan, V., & Amutha, A. (2026). Trends, clinical characteristics, and complications of individuals with type 1 and type 2 diabetes diagnosed below 25 years of age as seen at a tertiary care diabetes centre in India. BMC Endocrine Disorders. https://doi.org/10.1186/s12902-026-02535-0

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02535-0

Keywords: type 1 diabetes, type 2 diabetes, youth-onset diabetes, India, diabetic retinopathy, diabetic kidney disease, neuropathy, glycemic control, obesity, insulin resistance, diabetes registry, epidemiology